http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Wed, 15 May 2013 15:05:12 +0000 http://www.hindawi.com/journals/jaa/2013/568953/ Paola Stiuso, Michele Caraglia, Giuseppe De Rosa, and Antonio Giordano Copyright © 2013 Paola Stiuso et al. All rights reserved. Sun, 21 Apr 2013 15:43:03 +0000 http://www.hindawi.com/journals/jaa/2013/509056/ The resistance of growing human colon cancer cells to chemotherapy agents has been correlated to endogenous overexpression of stress proteins including the family of heat shock proteins (HSPs). Previously, we have demonstrated that a quinone-based mimetic dipeptide, named DTNQ-Pro, induced differentiation of growing Caco-2 cells through inhibition of HSP70 and HSP90. In addition, our product induced a HSP27 and vimentin intracellular redistribution. In the present study, we have evaluated whether a decrease of stress proteins induced by DTNQ-Pro in Caco-2 cells could sensitize these cells to treatment with 5-fluorouracil (5-FU) cytotoxicity. The pretreatment of Caco-2 with 500 nM of DTNQ-Pro increases lipid peroxidation and decreases expression of p38 mitogen-activated protein kinase (MAPK) and FOXO3a. At the same experimental conditions, an increase of the 5-FU-induced growth inhibition of Caco-2 cells was recorded. These effects could be due to enhanced DTNQ-Pro-induced membrane lipid peroxidation that, in turn, causes the sensitization of cancer cells to the cytotoxicity mediated by 5-FU. Isabel Gomez-Monterrey, Pietro Campiglia, Ilaria Scognamiglio, Daniela Vanacore, Alessandra Dicitore, Angela Lombardi, Michele Caraglia, Ettore Novellino, and Paola Stiuso Copyright © 2013 Isabel Gomez-Monterrey et al. All rights reserved. Thu, 21 Mar 2013 11:37:27 +0000 http://www.hindawi.com/journals/jaa/2013/240537/ Because taurine alleviates ethanol- (EtOH-) induced lipid peroxidation and liver damage in rats, we asked whether exogenous taurine could alleviate EtOH-induced oxidative stress in chick embryos. Exogenous EtOH (1.5 mmol/Kg egg or 3 mmol/Kg egg), taurine (4 mol/Kg egg), or EtOH and taurine (1.5 mmol EtOH and 4 mol taurine/Kg egg or 3 mmol EtOH and 4 mol taurine/Kg egg) were injected into fertile chicken eggs during the first three days of embryonic development (E0–2). At 11 days of development (midembryogenesis), serum taurine levels and brain caspase-3 activities, homocysteine (HoCys) levels, reduced glutathione (GSH) levels, membrane fatty acid composition, and lipid hydroperoxide (LPO) levels were measured. Early embryonic EtOH exposure caused increased brain apoptosis rates (caspase-3 activities); increased brain HoCys levels; increased oxidative-stress, as measured by decreased brain GSH levels; decreased brain long-chain polyunsaturated levels; and increased brain LPO levels. Although taurine is reported to be an antioxidant, exogenous taurine was embryopathic and caused increased apoptosis rates (caspase-3 activities); increased brain HoCys levels; increased oxidative-stress (decreased brain GSH levels); decreased brain long-chain polyunsaturated levels; and increased brain LPO levels. Combined EtOH and taurine treatments also caused increased apoptosis rates and oxidative stress. Emily J. Berning, Noah Bernhardson, Kelly Coleman, Dina A. Farhat, Courtney M. Gushrowski, Alison Lanctot, Benjamin H. Maddock, Kathryn G. Michels, Luke A. Mugge, Catherine M. Nass, Sarah M. Yearsley, and Robert R. Miller Jr. Copyright © 2013 Emily J. Berning et al. All rights reserved. Sun, 10 Mar 2013 15:06:29 +0000 http://www.hindawi.com/journals/jaa/2013/178381/ A number of matrix metalloproteinases (MMPs) are important medicinal targets for conditions ranging from rheumatoid arthritis to cardiomyopathy, periodontal disease, liver cirrhosis, multiple sclerosis, and cancer invasion and metastasis, where they showed to have a dual role, inhibiting or promoting important processes involved in the pathology. MMPs contain a zinc (II) ion in the protein active site. Small-molecule inhibitors of these metalloproteins are designed to bind directly to the active site metal ions. In an effort to devise new approaches to selective inhibitors, in this paper, we describe the synthesis and preliminary biological evaluation of amino acid derivatives as new zinc binding groups (ZBGs). The incorporation of selected metal-binding functions in more complex biphenyl sulfonamide moieties allowed the identification of one compound able to interact selectively with different MMP enzymatic isoforms. Mariateresa Giustiniano, Paolo Tortorella, Mariangela Agamennone, Antonella Di Pizio, Armando Rossello, Elisa Nuti, Isabel Gomez-Monterrey, Ettore Novellino, Pietro Campiglia, Ermelinda Vernieri, Marina Sala, Alessia Bertamino, and Alfonso Carotenuto Copyright © 2013 Mariateresa Giustiniano et al. All rights reserved. Tue, 26 Feb 2013 16:31:38 +0000 http://www.hindawi.com/journals/jaa/2013/939804/ Bovine milk possesses a protein system constituted by two major families of proteins: caseins (insoluble) and whey proteins (soluble). Caseins (αS1, αS2, β, and κ) are the predominant phosphoproteins in the milk of ruminants, accounting for about 80% of total protein, while the whey proteins, representing approximately 20% of milk protein fraction, include β-lactoglobulin, α-lactalbumin, immunoglobulins, bovine serum albumin, bovine lactoferrin, and lactoperoxidase, together with other minor components. Different bioactivities have been associated with these proteins. In many cases, caseins and whey proteins act as precursors of bioactive peptides that are released, in the body, by enzymatic proteolysis during gastrointestinal digestion or during food processing. The biologically active peptides are of particular interest in food science and nutrition because they have been shown to play physiological roles, including opioid-like features, as well as immunomodulant, antihypertensive, antimicrobial, antiviral, and antioxidant activities. In recent years, research has focused its attention on the ability of these molecules to provide a prevention against the development of cancer. This paper presents an overview of antitumor activity of caseins and whey proteins and derived peptides. Giacomo Pepe, Gian Carlo Tenore, Raffaella Mastrocinque, Paola Stusio, and Pietro Campiglia Copyright © 2013 Giacomo Pepe et al. All rights reserved. Tue, 26 Feb 2013 15:51:16 +0000 http://www.hindawi.com/journals/jaa/2013/606282/ Cyclooxygenase (COX) is a key enzyme in the biosynthetic pathway leading to the formation of prostaglandins, which are mediators of inflammation. It exists mainly in two isoforms COX-1 and COX-2. The conventional nonsteroidal anti-inflammatory drugs (NSAIDs) have gastrointestinal side effects because they inhibit both isoforms. Recent data demonstrate that the overexpression of these enzymes, and in particular of cyclooxygenases-2, promotes multiple events involved in tumorigenesis; in addition, numerous studies show that the inhibition of cyclooxygenases-2 can delay or prevent certain forms of cancer. Agents that inhibit COX-2 while sparing COX-1 represent a new attractive therapeutic development and offer a new perspective for a further use of COX-2 inhibitors. The present study extends the evaluation of the COX activity to all 203 possible natural tripeptide sequences following a rational approach consisting in molecular modeling, synthesis, and biological tests. Based on data obtained from virtual screening, only those peptides with better profile of affinity have been selected and classified into two groups called S and E. Our results suggest that these novel compounds may have potential as structural templates for the design and subsequent development of the new selective COX-2 inhibitors drugs. Ermelinda Vernieri, Isabel Gomez-Monterrey, Ciro Milite, Paolo Grieco, Simona Musella, Alessia Bertamino, Ilaria Scognamiglio, Stefano Alcaro, Anna Artese, Francesco Ortuso, Ettore Novellino, Marina Sala, and Pietro Campiglia Copyright © 2013 Ermelinda Vernieri et al. All rights reserved. Mon, 25 Feb 2013 17:23:41 +0000 http://www.hindawi.com/journals/jaa/2013/979016/ Urotensin-II was originally isolated from the goby urophysis in the 1960s as a vasoactive peptide with a prominent role in cardiovascular homeostasis. The identification of human isoform of urotensin-II and its specific UT receptor by Ames et al. in 1999 led to investigating the putative role of the interaction U-II/UT receptor in multiple pathophysiological effects in humans. Since urotensin-II is widely expressed in several peripheral tissues including cardiovascular system, the design and development of novel urotensin-II analogues can improve knowledge about structure-activity relationships (SAR). In particular, since the modulation of the U-II system offers a great potential for therapeutic strategies related to the treatment of several diseases, like cardiovascular diseases, the research of selective and potent ligands at UT receptor is more fascinating. In this paper, we review the developments of peptide and nonpeptide U-II structures so far developed in order to contribute also to a more rational and detectable design and synthesis of new molecules with high affinity at the UT receptor. Francesco Merlino, Salvatore Di Maro, Ali Munaim Yousif, Michele Caraglia, and Paolo Grieco Copyright © 2013 Francesco Merlino et al. All rights reserved. Sun, 17 Feb 2013 10:39:06 +0000 http://www.hindawi.com/journals/jaa/2013/569527/ A new cysteine protease named Nivulian-II has been purified from the latex of Euphorbia nivulia Buch.-Ham. The apparent molecular mass of Nivulian-II is 43670.846 Da (MALDI TOF/MS). Peptide mass fingerprint analysis revealed peptide matches to Maturase K (Q52ZV1_9MAGN) of Banksia quercifolia. The N-terminal sequence (DFPPNTCCCICC) showed partial homology with those of other cysteine proteinases of biological origin. This is the first paper to characterize a Nivulian-II of E. nivulia latex with respect to amino acid sequencing. Shamkant B. Badgujar and Raghunath T. Mahajan Copyright © 2013 Shamkant B. Badgujar and Raghunath T. Mahajan. All rights reserved. Mon, 04 Feb 2013 15:55:07 +0000 http://www.hindawi.com/journals/jaa/2013/461901/ Catabolite repression (CCR) regulates amino acid permeases in Saccharomyces cerevisiae via a TOR-kinase mediated mechanism. When glucose, the preferred fuel in S. cerevisiae, is substituted by galactose, amino acid uptake is increased. Here we have assessed the contribution and metabolic significance of this surfeit of amino acid in yeast undergoing catabolite derepression (CDR). L-[U-14C]leucine oxidation was increased 15 ± 1 fold in wild type (WT) strain grown in galactose compared to glucose. Under CDR, leucine oxidation was (i) proportional to uptake, as demonstrated by decreased uptake and oxidation of leucine in strains deleted of major leucine permeases and (ii) entirely dependent upon the TCA cycle, as cytochrome c1 (Cyt1) deleted strains could not grow in galactose. A regulator of amino acid carbon entry into the TCA cycle, branched chain ketoacid dehydrogenase, was also increased 29 ± 3 fold under CCR in WT strain. Protein expression of key TCA cycle enzymes, citrate synthase (Cs), and Cyt1 was increased during CDR. In summary, CDR upregulation of amino acid uptake is accompanied by increased utilization of amino acids for yeast growth. The mechanism for this is likely to be an increase in protein expression of key regulators of the TCA cycle. John S. Hothersall and Aamir Ahmed Copyright © 2013 John S. Hothersall and Aamir Ahmed. All rights reserved. Wed, 30 Jan 2013 11:05:34 +0000 http://www.hindawi.com/journals/jaa/2013/983565/ The transformation of the strain - with plasmid vector pET11a containing the cloned gene of bacterial selenophosphate synthetase (SPS), selD, from the E. coli BL21-Gold (DE3) strain gives an overproducing strain of SPS with one synonymic substitution, E197D. The transformation efficiency was estimated as 8 × 108 CFU/μg plasmid DNA. 28 mg of highly purified preparation of recombinant SPS capable of binding TNP-ATP was eluted from DEAE-Sephadex column in amount of 15 % from the total soluble protein in crude extract. The fluorescent derivative of ATP, 2′(3′)-O-(2,4,6-trinitrophenyl)adenosine-5′-triphosphate (TNP-ATP), was used as a synthetic analog of the substrate for the monitoring and quantitative analysis of the functional activity of SPS. The non-linear regression analysis of the saturation curve of TNP-ATP binding to D197 SPS with GraphPad Prism software fits to a model with 2 distinct binding sites with different in order. The SPS existence in a form of tetramer in given reaction conditions, in accordance with the concentration stoichiometry of 4 moles of TNP-ATP to 1 mole of recombinant protein, is being discussed. The tetramer structure was predicted with molecular modelling software YASARA and modelled in vacuum using steepest descent minimization energy method. We hypothesize here the recombinant SPS exists as a dimer in solution with two active sites capable of ATP binding in each subunit. Y. V. Preobrazhenskaya, A. I. Stenko, M. V. Shvarts, and V. Y. Lugovtsev Copyright © 2013 Y. V. Preobrazhenskaya et al. All rights reserved. Wed, 16 Jan 2013 10:43:00 +0000 http://www.hindawi.com/journals/jaa/2013/251398/ We have demonstrated that the peptide L-2 designed from an alanine scanning of the Limulus-derived LALF32-51 region is a potential candidate for the anticancer therapy and its cell-penetrating capacity is an associated useful property. By the modification in the primary structure of L-2, a second-generation peptide (CIGB-552) was developed. However, the molecular mechanism underlying its cytotoxic activity remains partially unknown. In this study, it was shown that CIGB-552 increases the levels of COMMD1, a protein involved in copper homeostasis, sodium transport, and the NF-κB signaling pathway. We found that CIGB-552 induces ubiquitination of RelA and inhibits the antiapoptotic activity regulated by NF-κB, whereas the knockdown of COMMD1 blocks this effect. We also found that CIGB-552 decreases the antioxidant capacity and induces the peroxidation of proteins and lipids in the tumor cells. Altogether, this study provides new insights into the mechanism of action of the peptide CIGB-552, which could be relevant in the design of future anticancer therapies. Julio R. Fernández Massó, Brizaida Oliva Argüelles, Yelaine Tejeda, Soledad Astrada, Hilda Garay, Osvaldo Reyes, Livan Delgado-Roche, Mariela Bollati-Fogolín, and Maribel G. Vallespí Copyright © 2013 Julio R. Fernández Massó et al. All rights reserved. Thu, 10 Jan 2013 11:19:42 +0000 http://www.hindawi.com/journals/jaa/2013/839036/ Ischemia enhanced release of endogenous neuroactive amino acids from cerebellar and cerebral cortical slices. More glutamate was released in adult than developing mice. Taurine release enhanced by K+ stimulation and ischemia was more than one magnitude greater than that of GABA or glutamate in the developing cerebral cortex and cerebellum, while in adults the releases were almost comparable. Aspartate release was prominently enhanced by both ischemia and K+ stimulation in the adult cerebral cortex. In the cerebellum K+ stimulation and ischemia evoked almost 10-fold greater GABA release in 3-month olds than in 7-day olds. The release of taurine increased severalfold in the cerebellum of 7-day-old mice in high-K+ media, whereas the K+-evoked effect was rather small in adults. In 3-month-old mice no effects of K+ stimulation or ischemia were seen in the release of aspartate, glycine, glutamine, alanine, serine, or threonine. The releases from the cerebral cortex and cerebellum were markedly different and also differed between developing and adult mice. In developing mice only the release of inhibitory taurine may be large enough to counteract the harmful effects of excitatory amino acids in ischemia in both cerebral cortex and cerebellum, in particular since at that age the release of glutamate and aspartate cannot be described as massive. Simo S. Oja and Pirjo Saransaari Copyright © 2013 Simo S. Oja and Pirjo Saransaari. All rights reserved. Thu, 20 Dec 2012 18:13:47 +0000 http://www.hindawi.com/journals/jaa/2012/967347/ This paper discusses the role of peptides in cancer therapy with special emphasis on peptide drugs which are already approved and those in clinical trials. The potential of peptides in cancer treatment is evident from a variety of different strategies that are available to address the progression of tumor growth and propagation of the disease. Use of peptides that can directly target cancer cells without affecting normal cells (targeted therapy) is evolving as an alternate strategy to conventional chemotherapy. Peptide can be utilized directly as a cytotoxic agent through various mechanisms or can act as a carrier of cytotoxic agents and radioisotopes by specifically targeting cancer cells. Peptide-based hormonal therapy has been extensively studied and utilized for the treatment of breast and prostate cancers. Tremendous amount of clinical data is currently available attesting to the efficiency of peptide-based cancer vaccines. Combination therapy is emerging as an important strategy to achieve synergistic effects in fighting cancer as a single method alone may not be efficient enough to yield positive results. Combining immunotherapy with conventional therapies such as radiation and chemotherapy or combining an anticancer peptide with a nonpeptidic cytotoxic drug is an example of this emerging field. Jyothi Thundimadathil Copyright © 2012 Jyothi Thundimadathil. All rights reserved. Thu, 20 Dec 2012 12:12:42 +0000 http://www.hindawi.com/journals/jaa/2012/415713/ Derek B. Oien, Gonzalo A. Carrasco, and Jackob Moskovitz Copyright © 2012 Derek B. Oien et al. All rights reserved. Tue, 11 Sep 2012 15:03:42 +0000 http://www.hindawi.com/journals/jaa/2012/493209/ Floating ferns of the genus Azolla detach their roots under stress conditions, a unique adaptive response termed rapid root abscission. We found that Azolla pinnata plants exhibited dose-dependent rapid root abscission in response to the polyamines spermidine and spermine after a substantial time lag (>20 min). The duration of the time lag decreased in response to high pH and high temperature whereas high light intensity increased the time lag and markedly lowered the rate of abscission. The oxidation products of polyamines, 1,3-diaminopropane, β-alanine and hydrogen peroxide all failed to initiate root abscission, and hydroxyethyl hydrazine, an inhibitor of polyamine oxidase, did not inhibit spermine-induced root abscission. Exposure of A. pinnata to the polyamines did not result in detectable release of NO and did not affect nitrite-dependent NO production. The finding of polyamine-induced rapid root abscission provides a facile assay for further study of the mode of action of polyamines in plant stress responses. Sushma Gurung, Michael F. Cohen, Jon Fukuto, and Hideo Yamasaki Copyright © 2012 Sushma Gurung et al. All rights reserved. Wed, 22 Aug 2012 11:42:11 +0000 http://www.hindawi.com/journals/jaa/2012/837932/ Polyamines are essential metabolites present in all living organisms, and this subject has attracted the attention of researchers worldwide interested in defining their mode of action in the variable cell functions in which they are involved, from growth to development and differentiation. Although the mechanism of polyamine synthesis is almost universal, different biological groups show interesting differences in this aspect that require to be further analyzed. For these studies, fungi represent interesting models because of their characteristics and facility of analysis. During the last decades fungi have contributed to the understanding of polyamine metabolism. The use of specific inhibitors and the isolation of mutants have allowed the manipulation of the pathway providing information on its regulation. During host-fungus interaction polyamine metabolism suffers striking changes in response to infection, which requires examination. Additionally the role of polyamine transporter is getting importance because of its role in polyamine regulation. In this paper we analyze the metabolism of polyamines in fungi, and the difference of this process with other biological groups. Of particular importance is the difference of polyamine biosynthesis between fungi and plants, which makes this process an attractive target for the control of phytopathogenic fungi. Laura Valdés-Santiago, José Antonio Cervantes-Chávez, Claudia Geraldine León-Ramírez, and José Ruiz-Herrera Copyright © 2012 Laura Valdés-Santiago et al. All rights reserved. Sun, 22 Jul 2012 13:58:21 +0000 http://www.hindawi.com/journals/jaa/2012/735076/ Tryptophyl glycine (TrpGly) and glycyl tryptophan (GlyTrp) dipeptides at pH 5.5 and pH 9.3 show a pattern of fluorescence emission shifts with the TrpGly zwitterion emission solely blue shifted. This pattern is matched by shifts in the UV resonance Raman (UVRR) W10 band position and the W7 Fermi doublet band ratio. Ab initio calculations show that the 1340 cm−1 band of the W7 doublet is composed of three modes, two of which determine the W7 band ratios for the dipeptides. Molecular dynamics simulations show that the dipeptides take on two conformations: one with the peptide backbone extended; one with the backbone curled over the indole. The dihedral angle critical to these conformations is 𝜒1 and takes on three discrete values. Only the TrpGly zwitterion spends an appreciable amount of time in the extended backbone conformation as this is stabilized by two hydrogen bonds with the terminal amine cation. According to a Stark effect model, a positive charge near the pyrrole keeps the 1La transition at high energy, limiting fluorescence emission red shift, as observed for the TrpGly zwitterion. The hydrogen bond stabilized backbone provides a rationale for the Cmethylene-C𝛼-Ccarbonyl W10 symmetric stretch that is unique to the TrpGly zwitterion. Azaria Solomon Eisenberg and Laura J. Juszczak Copyright © 2012 Azaria Solomon Eisenberg and Laura J. Juszczak. All rights reserved. Mon, 09 Jul 2012 11:51:11 +0000 http://www.hindawi.com/journals/jaa/2012/691463/ The primary products of the metastasis-suppressor KiSS-1 gene are the kisspeptin (KP) peptides that stimulate gonadotrophin-releasing-hormone (GnRH) release via GPR-54 receptor activation. Recent studies have suggested that the KP-10 peptide also activates neuropeptide FF (NPFF) receptors. The aim of the current study was to determine the activities of the KiSS-1 derivative kissorphin (KSO), which contains the first six amino acids of the KP-10 peptide, is C-terminally amidated, and shares amino acid similarities with the biologically active NPFF 3–8 sequence. The KSO peptide inhibited forskolin-stimulated cyclic adenosine monophosphate (cAMP) production in ND7/23 neuroblastoma cells via an action that could be inhibited by the NPFF receptor antagonist RF9. Release of GnRH by LA-N-1 neuroblastoma cells was not altered by the KSO peptide. In ND7/23 neuroblastoma cells, the KSO peptide was able to reduce forskolin neuroprotection against H2O2 toxicity. The KSO peptide was also able to prevent prostaglandin E2-induced apoptosis in rat cortical neurons. The NPFF receptor antagonist RF9 could inhibit these actions of the KSO peptide in oxidative stress and apoptosis models. In conclusion, the kissorphin peptide, comprising the amino acid sequence Tyr-Asn-Trp-Asn-Ser-Phe-NH2, has NPFF-like biological activity without showing any GnRH releasing activity and inhibits forskolin-activated cAMP release. Nathaniel G. N. Milton Copyright © 2012 Nathaniel G. N. Milton. All rights reserved. Tue, 29 May 2012 13:08:33 +0000 http://www.hindawi.com/journals/jaa/2012/831759/ Functional roles of amino acids have increasingly become the focus of research. This paper summarizes amino acids that influence cardiovascular system via the brain of conscious rats. This paper firstly describes why amino acids are selected and outlines how the brain regulates blood pressure and regional blood flow. This section includes a concise history of amino acid neurotransmitters in cardiovascular research and summarizes brain areas where chemical stimulations produce blood pressure changes mainly in anesthetized animals. This is followed by comments about findings regarding several newly examined amino acids with intracisternal stimulation in conscious rats that produce changes in blood pressure. The same pressor or depressor response to central amino acid stimulations can be produced by distinct mechanisms at central and peripheral levels, which will be briefly explained. Thereafter, cardiovascular actions of some of amino acids at the mechanism level will be discussed based upon findings of pharmacological and regional blood flow measurements. Several examined amino acids in addition to the established neurotransmitter amino acids appear to differentially activate brain structures to produce changes in blood pressure and regional blood flows. They may have physiological roles in the healthy brain, but pathological roles in the brain with cerebral vascular diseases such as stroke where the blood-brain barrier is broken. Yumi Takemoto Copyright © 2012 Yumi Takemoto. All rights reserved. Mon, 14 May 2012 14:34:44 +0000 http://www.hindawi.com/journals/jaa/2012/565404/ 2D, 13C, 14N, and 17O NMR and crystallographic data from the literature were critically evaluated in order to provide a coherent hydration model of amino acids and selected derivatives at different ionization states. 17O shielding variations, longitudinal relaxation times (T1) of 2D and 13C and line widths (Δν1/2) of 14N and 17O, may be interpreted with the hypothesis that the cationic form of amino acids is more hydrated by 1 to 3 molecules of water than the zwitterionic form. Similar behaviour was also observed for N-acetylated derivatives of amino acids. An exhaustive search in crystal structure databases demonstrates the importance of six-membered hydrogen-bonded conjugated rings of both oxygens of the α-carboxylate group with a molecule of water in the vicinity. This type of hydrogen bond mode is absent in the case of the carboxylic groups. Moreover, a considerable number of structures was identified with the propensity to form intramolecular hydrogen bond both in the carboxylic acid (NH⋯O=C) and in the carboxylate (NH⋯O−) ionization state. In the presence of bound molecules of water this interaction is significantly reduced in the case of the carboxylate group whereas it is statistically negligible in the carboxylic group. Charalampos G. Pappas, Andreas G. Tzakos, and Ioannis P. Gerothanassis Copyright © 2012 Charalampos G. Pappas et al. All rights reserved. Wed, 18 Apr 2012 11:57:04 +0000 http://www.hindawi.com/journals/jaa/2012/382107/ Posttranslational modification of proteins is a ubiquitous cellular mechanism for regulating protein function. Some of the most heavily modified neuronal proteins are cytoskeletal proteins of long myelinated axons referred to as neurofilaments (NFs). NFs are type IV intermediate filaments (IFs) that can be composed of four subunits, neurofilament heavy (NF-H), neurofilament medium (NF-M), neurofilament light (NF-L), and α-internexin. Within wild type axons, NFs are responsible for mediating radial growth, a process that determines axonal diameter. NFs are phosphorylated on highly conserved lysine-serine-proline (KSP) repeats located along the C-termini of both NF-M and NF-H within myelinated axonal regions. Phosphorylation is thought to regulate aspects of NF transport and function. However, a key pathological hallmark of several neurodegenerative diseases is ectopic accumulation and phosphorylation of NFs. The goal of this review is to provide an overview of the posttranslational modifications that occur in both normal and diseased axons. We review evidence that challenges the role of KSP phosphorylation as essential for radial growth and suggests an alternative role for NF phosphorylation in myelinated axons. Furthermore, we demonstrate that regulation of NF phosphorylation dynamics may be essential to avoiding NF accumulations. Jeffrey M. Dale and Michael L. Garcia Copyright © 2012 Jeffrey M. Dale and Michael L. Garcia. All rights reserved. Wed, 18 Apr 2012 10:12:29 +0000 http://www.hindawi.com/journals/jaa/2012/356081/ Initially implicated in the pathogenesis of CFTR and HIV-1 transcription, nuclear factor TDP-43 was subsequently found to be involved in the origin and development of several neurodegenerative diseases. In 2006, in fact, it was reported for the first time the cytoplasmic accumulation of TDP-43 in ubiquitin-positive inclusions of ALS and FTLD patients, suggesting the presence of a shared underlying mechanism for these diseases. Today, different animal models of TDP-43 proteinopathies are available in rodents, nematodes, fishes, and flies. Although these models recapitulate several of the pathological features found in patients, the mechanisms underpinning the progressive neuronal loss observed in TDP-43 proteinopathies remain to be characterized. Compared to other models, Drosophila are appealing because they combine the presence of a sophisticated brain with the possibility to investigate quickly and massively phenotypic genetic modifiers as well as possible therapeutic strategies. At present, the development of TDP-43-related Drosophila models has further strengthened the hypothesis that both TDP-43 “loss-of-function” and “gain-of-function” mechanisms can contribute to disease. The aim of this paper is to describe and compare the results obtained in a series of transgenic and knockout flies, along with the information they have generated, towards a better understanding of the mechanisms underlying TDP-43 proteinopathies. Maurizio Romano, Fabian Feiguin, and Emanuele Buratti Copyright © 2012 Maurizio Romano et al. All rights reserved. Sun, 25 Mar 2012 15:08:06 +0000 http://www.hindawi.com/journals/jaa/2012/463183/ A new nonlinear optical organic compound, namely, L-histidinium 2-nitrobenzoate (abbreviated as LH2NB (I); ([C6H10N3O2]+ [C7H4NO4]−)), was synthesized. The molecular structure of LH2NB (I) was elucidated using single crystal X-ray diffraction technique. The second harmonic generation (SHG) efficiency of this compound is about two times that of the standard potassium dihydrogen phosphate crystals. Subramanian Natarajan, Kalimuthu Moovendaran, Jeyaperumal Kalyana Sundar, and Krishnan Ravikumar Copyright © 2012 Subramanian Natarajan et al. All rights reserved. Thu, 01 Mar 2012 10:19:25 +0000 http://www.hindawi.com/journals/jaa/2012/575180/ Rotavirus (RV) NSP4, the first described viral enterotoxin, is a multifunctional glycoprotein that contributes to viral pathogenesis, morphogenesis, and replication. NSP4 binds both termini of caveolin-1 and is isolated from caveolae fractions that are rich in anionic phospholipids and cholesterol. These interactions indicate that cholesterol/caveolin-1 plays a role in NSP4 transport to the cell surface, which is essential to its enterotoxic activity. Synthetic peptides were utilized to identify target(s) of intervention by exploring the NSP4-caveolin-1 and -cholesterol interactions. NSP4112–140 that overlaps the caveolin-1 binding domain and a cholesterol recognition amino acid consensus (CRAC) motif and both termini of caveolin-1 (N-caveolin-12–20,  19–40 and C-caveolin-1161–180) were synthesized. Direct fluorescence-binding assays were employed to determine binding affinities of the NSP4-caveolin-1 peptides and cholesterol. Intracellular cholesterol alteration revealed a redistribution of NSP4 and disintegration of viroplasms. These data further imply interruption of NSP4112–140-N-caveolin-119–40 and cholesterol interactions may block NSP4 intracellular transport, hence enterotoxicity. Megan E. Schroeder, Heather A. Hostetler, Friedhelm Schroeder, and Judith M. Ball Copyright © 2012 Megan E. Schroeder et al. All rights reserved. Tue, 28 Feb 2012 09:37:03 +0000 http://www.hindawi.com/journals/jaa/2012/816032/ Several proteins, like transcription factors, bind to certain DNA sequences, thereby regulating biochemical pathways that determine the fate of the corresponding cell. Due to these key positions, it is indispensable to analyze protein-DNA interactions and to identify their mode of action. Surface plasmon resonance is a label-free method that facilitates the elucidation of real-time kinetics of biomolecular interactions. In this article, we focus on this biosensor-based method and provide a detailed guide how SPR can be utilized to study binding of proteins to oligonucleotides. After a description of the physical phenomenon and the instrumental realization including fiber-optic-based SPR and SPR imaging, we will continue with a survey of immobilization methods. Subsequently, we will focus on the optimization of the experiment, expose pitfalls, and introduce how data should be analyzed and published. Finally, we summarize several interesting publications of the last decades dealing with protein-DNA and RNA interaction analysis by SPR. Markus Ritzefeld and Norbert Sewald Copyright © 2012 Markus Ritzefeld and Norbert Sewald. All rights reserved. Tue, 28 Feb 2012 08:40:09 +0000 http://www.hindawi.com/journals/jaa/2012/736837/ Glutathione (GSH) is a tripeptide, which has many biological roles including protection against reactive oxygen and nitrogen species. The primary goal of this paper is to characterize the principal mechanisms of the protective role of GSH against reactive species and electrophiles. The ancillary goals are to provide up-to-date knowledge of GSH biosynthesis, hydrolysis, and utilization; intracellular compartmentalization and interorgan transfer; elimination of endogenously produced toxicants; involvement in metal homeostasis; glutathione-related enzymes and their regulation; glutathionylation of sulfhydryls. Individual sections are devoted to the relationships between GSH homeostasis and pathologies as well as to developed research tools and pharmacological approaches to manipulating GSH levels. Special attention is paid to compounds mainly of a natural origin (phytochemicals) which affect GSH-related processes. The paper provides starting points for development of novel tools and provides a hypothesis for investigation of the physiology and biochemistry of glutathione with a focus on human and animal health. Volodymyr I. Lushchak Copyright © 2012 Volodymyr I. Lushchak. All rights reserved. Wed, 08 Feb 2012 08:30:20 +0000 http://www.hindawi.com/journals/jaa/2012/206520/ We present here environmental factors including pH shifts, temperature, and metal ions surrounding Aβ40 monomer to precede the oligomers. We also suggest a new idea to detect Aβ40 oligomers with anti-Aβ40 monoclonal antibody using enzyme-linked immunosorbent assay. This method involves the different sensitivity of the thermal shifts between Aβ40 monomer and the oligomers. The idea is useful for the diagnostics of Alzheimer's disease to detect Aβ40 oligomers in the serum from the patients. Yoichi Matsunaga and Midori Suenaga Copyright © 2012 Yoichi Matsunaga and Midori Suenaga. All rights reserved. Thu, 19 Jan 2012 09:38:20 +0000 http://www.hindawi.com/journals/jaa/2012/206083/ Topoisomerases I are ubiquitous enzymes that control DNA topology within the cell. They are the unique target of the antitumor drug camptothecin that selectively recognizes the DNA-topoisomerase covalent complex and reversibly stabilizes it. The biochemical and structural-dynamical properties of the Asp677Gly-Val703Ile double mutant with enhanced CPT sensitivity have been investigated. The mutant displays a lower religation rate of the DNA substrate when compared to the wild-type protein. Analyses of the structural dynamical properties by molecular dynamics simulation show that the mutant has reduced flexibility and an active site partially destructured at the level of the Lys532 residue. These results demonstrate long-range communication mechanism where reduction of the linker flexibility alters the active site geometry with the consequent lowering of the religation rate and increase in drug sensitivity. Ilda D'Annessa, Cinzia Tesauro, Paola Fiorani, Giovanni Chillemi, Silvia Castelli, Oscar Vassallo, Giovanni Capranico, and Alessandro Desideri Copyright © 2012 Ilda D'Annessa et al. All rights reserved. Mon, 28 Nov 2011 15:04:20 +0000 http://www.hindawi.com/journals/jaa/2011/517137/ The processes of differentiation, proliferation, and apoptosis were studied in a cell culture of human cortical thymocytes under the influence of short peptides T-32 (Glu-Asp-Ala) and T-38 (Lys-Glu-Asp). Peptides T-32 and T-38 amplified cortical thymocytes differentiation towards regulatory T cells, increased their proliferative activity, and decreased the level of apoptosis. Moreover, peptides under study stimulated proliferative and antiapoptotic activity of the mature regulatory T cells. V. Kh. Khavinson, V. O. Polyakova, N. S. Linkova, A. V. Dudkov, and I. M. Kvetnoy Copyright © 2011 V. Kh. Khavinson et al. All rights reserved. Sun, 20 Nov 2011 09:50:43 +0000 http://www.hindawi.com/journals/jaa/2011/594646/ Nabil Miled, Moncef Nasri, Hideki Kishimura, and Faouzi Ben Rebah Copyright © 2011 Nabil Miled et al. All rights reserved.