The effect of acidic pH on the adsorption and lytic activity of the peptides Polybia-MP1 and its histidine-containing analog in anionic lipid membrane: a biophysical study by molecular dynamics and spectroscopy.

Antimicrobial peptides (AMPs) are part of the innate immune system of many species. AMPs are short sequences rich in charged and non-polar residues. They act on the lipid phase of the plasma membrane without requiring membrane receptors. Polybia-MP1 (MP1), extracted from a native wasp, is a broad-spectrum bactericide, an inhibitor of cancer cell proliferation being non-hemolytic and non-cytotoxic. MP1 mechanism of action and its adsorption mode is not yet completely known. Its adsorption to lipid bilayer and lytic activity is most likely dependent on the ionization state of its two acidic and three basic residues and consequently on the bulk pH. Here we investigated the effect of bulk acidic (pH 5.5) and neutral pH (7.4) solution on the adsorption, insertion, and lytic activity of MP1 and its analog H-MP1 to anionic (7POPC:3POPG) model membrane. H-MP1 is a synthetic analog of MP1 with lysines replaced by histidines. Bulk pH changes could modulate this peptide efficiency. The combination of different experimental techniques and molecular dynamics (MD) simulations showed that the adsorption, insertion, and lytic activity of H-MP1 are highly sensitive to bulk pH in opposition to MP1. The atomistic details, provided by MD simulations, showed peptides contact their N-termini to the bilayer before the insertion and then lay parallel to the bilayer. Their hydrophobic faces inserted into the acyl chain phase disturb the lipid-packing.

Comparative study between fructose 1-6 bisphosphate and histidine-tryptophan-ketoglutarate in liver preservation in rats submitted to total cold ischemia

Purpose To compare Fructose-1,6-Bisphosphate (FBP) to Histidine-Tryptophan-Ketoglutarate (HTK) in liver preservation at cold ischemia. Methods Male rats (Sprague-Dawley: 280-340g) divided into three groups (n=7): Control; Fructose-1,6-bisphosphate (FBP); Histidine-Tryptophan-Ketoglutarate (HTK). Animals underwent laparotomy-thoracotomy for perfusion of livers with saline. Livers were removed and deposited into solutions. Mitochondria were isolated to determine State 3 (S3), State 4 (S4), Respiratory Control Ratio (RCR) and Swelling (S). Liver enzymes (AST, ALT, LDH) were determined in solution. At tissue, Malondialdehyde (MDA) and Nitrate (NOx) were determined. All parameters were analyzed at 0.6 and 24 hours of hypothermic preservation. Statistics analysis were made by Mann-Whitney test (p 0.05). Results Regarding ALT, there was a difference between FBP-6h/HTK-6h, lower in HTK. Regarding AST, there was a significant difference between FBP-24h/HTK-24h, lower in FBP. Regarding NOx, there was a difference between 0h and 6h, as well as 0h and 24h for both solutions. Regarding S3, there was a significant difference in 24h compared to Control-0h for both solutions, and a significant difference between FBP-6h/FBP-24h. Regarding S4, there was a difference between Control-0h/HTK-24h and FBP-24h/HTK-24h, higher in HTK. There was a difference between Control-0h/FBP-24h for Swelling, higher in FBP. Conclusion Fructose-1,6-Bisphosphate showed better performance at nitrate and aspartate aminotransferase compared to histidine-tryptophan-ketoglutarate.(AU)

Comparative study between fructose 1-6 bisphosphate and histidine-tryptophan-ketoglutarate in liver preservation in rats submitted to total cold ischemia

Purpose. To compare Fructose-1,6-Bisphosphate (FBP) to Histidine-Tryptophan-Ketoglutarate (HTK) in liver preservation at cold ischemia.. Methods. Male rats (Sprague-Dawley: 280-340g) divided into three groups (n=7): Control; Fructose-1,6-bisphosphate (FBP); Histidine-Tryptophan-Ketoglutarate (HTK). Animals underwent laparotomy-thoracotomy for perfusion of livers with saline. Livers were removed and deposited into solutions. Mitochondria were isolated to determine State 3 (S3), State 4 (S4), Respiratory Control Ratio (RCR) and Swelling (S). Liver enzymes (AST, ALT, LDH) were determined in solution. At tissue, Malondialdehyde (MDA) and Nitrate (NOx) were determined. All parameters were analyzed at 0.6 and 24 hours of hypothermic preservation. Statistics analysis were made by Mann-Whitney test (p<0.05).. Results. Regarding ALT, there was a difference between FBP-6h/HTK-6h, lower in HTK. Regarding AST, there was a significant difference between FBP-24h/HTK-24h, lower in FBP. Regarding NOx, there was a difference between 0h and 6h, as well as 0h and 24h for both solutions. Regarding S3, there was a significant difference in 24h compared to Control-0h for both solutions, and a significant difference between FBP-6h/FBP-24h. Regarding S4, there was a difference between Control-0h/HTK-24h and FBP-24h/HTK-24h, higher in HTK. There was a difference between Control-0h/FBP-24h for Swelling, higher in FBP.. Conclusion. Fructose-1,6-Bisphosphate showed better performance at nitrate and aspartate aminotransferase compared to histidine-tryptophan-ketoglutarate.(AU)

Photochemical oxidation of alcohols: Simple derivatization strategy for their analysis by capillary electrophoresis.

The determination of ethanol is one of the most important parameters in the fermentation industry, influencing not only the production yield and the quality of the product, but also its commercial value. In addition to the traditional approach based on distillation/density, procedure that is considered laborious and time-consuming, methods based on chromatography are widely used. Alternatives using electrochemical, spectroscopic and colorimetric techniques have been also proposed for alcohol analysis. In general, these methods not only offer limited throughput, but also require harsh reaction conditions and/or complex instrumentation. Aiming to address these shortcomings, we propose a fast, simple and clean analytical approach for the determination of primary alcohols based on the photochemical oxidation under UV-LED irradiation in the presence of H2O2. The proposed method was successfully applied to the analysis of 12 different types of alcoholic beverages with an alcohol content ranging from 5% v/v (beer) to 53% v/v (whiskey).

Histidinemia atípica y desarrollo cognitivo / Atypical hystidinemia and the cognitive development

Introducción: la histidinemia es un defecto metabólico dentro del grupo de aminoacidemias. El defecto enzimático de la histidasa (histidin-amono-liasa) provoca alta concentración de histidina en sangre, líquido cefalorraquídeo, en la orina y en el sudor. Métodos: un estudio de caso muestra el desarrollo evolutivo de un niño con histidinemia atípica y el impacto de la rehabilitación desde la edad temprana hasta la edad escolar. Resultados: la condición patológica causada por la histidinemia atípica limita el desarrollo motor, neurológico, neuropsicológico, conductual y escolar del niño. La rehabilitación temprana muestra que las habilidades primarias de la marcha se adquieren en la etapa esperada, pero los problemas motores complejos mantienen su limitación en el desarrollo. Las dificultades en el lenguaje oral persisten en toda la edad temprana, la rehabilitación posibilita su perfeccionamiento con la edad. Conclusiones: la histidinemia atípica muestra en el desarrollo alteraciones neurológicas, neuropsicológicas, neurofisiológicas, conductuales y académicas. La rehabilitación temprana brinda mejores condiciones de vida del infante. El carácter crónico de la enfermedad posibilita un pronóstico negativo en áreas esenciales como la conducta y la vida escolar.(AU)

Introduction: histidinemia is a metabolic defect within the group of aminoacidemias. The enzymatic defect of histidase (histidin-amono-lyase) cause high histidine concentration in the blood, the cerebrospinal fluid, in urine, and sweat. Methods: a case study showed the developmental evolution of a child with atypical histidinemia and the impact of rehabilitation from early age to school age. Results: the pathological condition caused by atypical histidinemia limits the motor, neurological, neuropsychological, behavioural and educational development of the child. The early rehabilitation shows that primary gait abilities are acquired in the expected phase, but the complex motor problems remained in the development phase. The language difficulties persist throughout the early childhood, but rehabilitation makes it possible to improve oral expression as age increases. Conclusions: atypical histidinemia reveals neurological, neuropsychological, neurophysiological, behavioural and academic alterations in the development of the child. The early rehabilitation provides better living conditions to the child. The chronic nature of the disease indicates a negative prognosis in essential areas such as behaviour and education.(AU)

Histidinemia atípica y desarrollo cognitivo / Atypical hystidinemia and the cognitive development

Introducción: la histidinemia es un defecto metabólico dentro del grupo de aminoacidemias. El defecto enzimático de la histidasa (histidin-amono-liasa) provoca alta concentración de histidina en sangre, líquido cefalorraquídeo, en la orina y en el sudor. Métodos: un estudio de caso muestra el desarrollo evolutivo de un niño con histidinemia atípica y el impacto de la rehabilitación desde la edad temprana hasta la edad escolar. Resultados: la condición patológica causada por la histidinemia atípica limita el desarrollo motor, neurológico, neuropsicológico, conductual y escolar del niño. La rehabilitación temprana muestra que las habilidades primarias de la marcha se adquieren en la etapa esperada, pero los problemas motores complejos mantienen su limitación en el desarrollo. Las dificultades en el lenguaje oral persisten en toda la edad temprana, la rehabilitación posibilita su perfeccionamiento con la edad. Conclusiones: la histidinemia atípica muestra en el desarrollo alteraciones neurológicas, neuropsicológicas, neurofisiológicas, conductuales y académicas. La rehabilitación temprana brinda mejores condiciones de vida del infante. El carácter crónico de la enfermedad posibilita un pronóstico negativo en áreas esenciales como la conducta y la vida escolar(AU)

Introduction: histidinemia is a metabolic defect within the group of aminoacidemias. The enzymatic defect of histidase (histidin-amono-lyase) cause high histidine concentration in the blood, the cerebrospinal fluid, in urine, and sweat. Methods: a case study showed the developmental evolution of a child with atypical histidinemia and the impact of rehabilitation from early age to school age. Results: the pathological condition caused by atypical histidinemia limits the motor, neurological, neuropsychological, behavioural and educational development of the child. The early rehabilitation shows that primary gait abilities are acquired in the expected phase, but the complex motor problems remained in the development phase. The language difficulties persist throughout the early childhood, but rehabilitation makes it possible to improve oral expression as age increases. Conclusions: atypical histidinemia reveals neurological, neuropsychological, neurophysiological, behavioural and academic alterations in the development of the child. The early rehabilitation provides better living conditions to the child. The chronic nature of the disease indicates a negative prognosis in essential areas such as behaviour and education(AU)

CheShift-2: graphic validation of protein structures.

UNLABELLED: The differences between observed and predicted (13)C(α) chemical shifts can be used as a sensitive probe with which to detect possible local flaws in protein structures. For this reason, we previously introduced CheShift, a Web server for protein structure validation. Now, we present CheShift-2 in which a graphical user interface is implemented to render such local flaws easily visible. A series of applications to 15 ensembles of conformations illustrate the ability of CheShift-2 to locate the main structural flaws rapidly and accurately on a per-residue basis. Since accuracy plays a central role in CheShift predictions, the treatment of histidine (His) is investigated here by exploring which form of His should be used in CheShift-2. AVAILABILITY: CheShift-2 is free of charge for academic use and can be accessed from www.cheshift.com

Histidinemia y Trastornos del lenguaje en una muestra de la población cubana / Histidinemia and language disorders: case study and controls in a sample of the Cuban population

La histidinemia es uno de los errores innatos más frecuentes en la infancia, su incidencia es alrededor de 1:15 000. Su manifestación más notable es el trastorno del lenguaje. Se realizó un estudio analítico de casos y controles. Se estudiaron 20 niños con trastornos del lenguaje de causa desconocida, que constituyeron los casos. Los controles fueron 50 niños sin alteraciones del lenguaje. En ambos grupos la concentración de histidina en suero fue determinada por los métodos espectrofluorimétrico y ultramicroanalítico. Ambos procederes mostraron que la probabilidad de encontrar niveles del histidina en un individuo con desórdenes aislados del lenguaje, de causa desconocida, fue treinta veces más alta que los observados en el grupo control. El segundo método demostró ser una herramienta útil para la determinación de los valores de histidina en suero(AU)

Histidinemia is one of the most frequent innate errors during childhood with a prevalence of nearly 1:15 000, speech disorder being its more remarkable result. An analytical study of cases was carried out to twenty children with language disorders due to unknown cause, while the control group was formed by 50 children without language alterations. In both groups the concentration of histidine in serum was determined by the fluorometric spectrometry and ultramicroanalytic methods. Both procedures showed that the probability of finding high levels of histidine in an individual with isolated language disorders of unknown cause was thirty times higher than the one observed in the control group. The second method also demonstrated being a useful tool for the determination of histidine levels in serum(AU)

Studies of the photooxidant properties of antibacterial fluoroquinolones and their naphthalene derivatives.

We synthesized and determined the production of reactive oxygen species (ROS) as 1O2, *-O2, *OH, H2O2 during the photolysis with UV-A light of three antibacterial quinolones and their naphthyl ester derivatives. Singlet oxygen and ROS dose-dependant generation from norfloxacin (1), enoxacin (2), ciprofloxacin (3) and their respective naphthyl ester derivatives 4-6 were detecting in cell-free systems by the histidine assay and by luminol-enhanced chemiluminescence (LCL). Both the electronic absorption and emission spectra were quantified and their photostability determined. The antibacterial activity in darkness and under irradiation of compounds 4, 5 and 6 was tested on E. coli and compared with their parent drugs.

RNA recognition motif-type RNA-binding proteins in Trypanosoma cruzi form a family involved in the interaction with specific transcripts in vivo.

Trypanosomes, protozoan parasites from the order Kinetoplastida, have to deal with environmental changes during the interaction with their hosts. Trypanosoma cruzi, the causative agent of Chagas' disease, uses post-transcriptional mechanisms to regulate gene expression. However, few RNA-binding proteins involved in mRNA turnover control have been identified to date. In this work, an RNA recognition motif (RRM)-type RNA-binding protein family named T. cruzi RNA-binding protein (TcRBP) and composed of at least six members was identified. The genomic organization of four members revealed a head to tail arrangement within a region of 15 kilobase pairs. TcRBP members have a common RRM and different auxiliary domains with a high content of glycine, glutamine, and histidine residues within their N- and C-terminal regions. TcRBPs differ in their expression patterns as well as in their homoribopolymer binding interaction in vitro, although they preferentially recognize poly(U) and poly(G) RNAs. An interesting observation was the relaxed RNA-binding interactions with several trypanosome transcripts in vitro. In contrast, co-immunoprecipitation experiments of TcRBP-containing ribonucleoprotein complexes formed in vivo revealed a highly restricted binding interaction with specific RNAs. Several TcRBP-containing complexes are stage-specific and, in some cases, bear the poly(A)-binding protein TcPABP1. Altogether, these results suggest that TcRBPs might be modulated in vivo, to favor or preclude the interaction with specific transcripts in a developmentally regulated manner.

Localization of histidine residues relevant for the binding of alpha-bungarotoxin to the acetylcholine receptor alpha-subunit in V8-proteolytic fragments.

Histidine residues have been shown to be critical for alpha-BgTx binding to the acetylcholine receptor (Lacorazza et al., 1992; Bouzat et al., 1993; Lacorazza et al., 1995). Receptor subunits from Discopyge tschudii were modified with diethylpyrocarbonate (DEP). DEP treatment produces a concentration-dependent decrease of [125I] alpha-BgTx binding to the alpha-subunit. The neurotoxin binding capacity was fully restored by adding the nucleophile hydroxylamine. By proteolytic mapping of the alpha-subunit with V8-protease, we determined that the binding capacity to the fragment alpha V8-19 decreased 80% by DEP treatment. In addition, the [125I] alpha-BgTx binding to the same fragment decreased by 70% when the subunits were reduced and affinity-alkylated. We report the N-terminal sequence of both subunits and V8-fragments (alpha V8-10, alpha V8-13, and alpha V8-18), which constitute a first contribution to the knowledge of the primary structure of the Discopyge tschudii receptor. We propose that the fragment alpha V8-19 contains one or more of the histidine residues involved in the alpha-BgTx binding and probably includes the Cys alpha 192-193 disulfide bond. Only two histidine residues are present in the extracellular sequence of Torpedo californica for such fragments: His alpha 186 and alpha 204.

An unknown hydrolase activity of human serum albumin: beta-lactamase activity.

The interaction of a chromogenic cephalosporin, 3-(2, 4 dinitrostyryl)-(6 R, 7 R) -7(2 thienylacetamido)-ceph 3-em-5-carboxylic acid) (nitrocefin) with human serum albumin was studied. Purified human albumin was showed to have a hydrolase activity, catalyzing the decomposition of the chromogenic cephalosporin. The dimeric and trimeric form of albumin also showed this hydrolase activity. The presence of the following amino acid residues at the catalytic site of albumin was demonstrated: tyrosyls 199 and 411, tryptophan 214, lysyls 195, 225 and 240, histidyl 146, also some argynyls were involucrated.

Is histidine essential for the adult man? A review.

Recent experimental observations as well as theoretical considerations suggest that histidine may be an essential amino acid for the adult man. In this paper, an up-to-date review of the literature on the essentiality of histidine is presented. Some practical implications of the indispensability of this amino acid in the human diet are also discussed.