Cryptosporidium parvum spermidine/spermine N1-acetyltransferase exhibits different characteristics from the host enzyme.

Cryptosporidosis is a severe opportunistic infection of immuno-compromised individuals for which no reliable therapy exists. The parasite scavenges host-derived polyamines, particularly spermine, which is then converted to the lower polyamines by the combined action of spermidine/spermine N(1)-acetyltransferase (SSAT) and polyamine oxidase (PAO). We have isolated and expressed the Cryptosporidium parvum SSAT for kinetic and molecular comparison with the host enzyme. The CpSSAT is a homotetramer with a subunit molecular mass of 18 kDa and low sequence similarity to higher eukaryotes but maintains the critical arginine residues in the active site. The CpSSAT had an activity of 299 nmol(-1)min(-1)(mg of protein)(-1) and exhibits an ordered Bi-Bi kinetics with preferred substrate specificity for spermine. Polyamine analogues having unsaturated central carbons were found to exhibit mixed inhibition kinetics of the CpSSAT. The cis-analogues were more effective inhibitors of the CpSSAT with lower K(i) values than the trans-analogues. Experiments aimed at determining the ratio of the time of the analogue in the enzyme active site to that spent out (in-out time: delta ln E/deltat) confirmed the higher efficiency of the cis-analogues as inhibitors of the CpSSAT. The results of this study reveal that the C. parvum SSAT may provide a rational target for drug design.

Bacterial-like energy metabolism in the amitochondriate protozoon Hexamita inflata.

Hexamita inflata is an amitochondriate flagellated protozoon which inhabits O(2)-limited environments. With the aid of 1H NMR spectroscopy, analysis of the metabolic fluxes in H. inflata grown in complex media under limited O(2) was performed. Almost complete carbon recovery from maltose (the principle carbohydrate source in the medium) catabolism was calculated from the measured increase in concentration of ethanol, alanine, acetate and lactate (and estimated CO(2) production). Difference spectra and amino acid analysis also identified changes in concentration of metabolites belonging to the arginine dihydrolase (ADH) pathway. The enzymes of the ADH pathway were detected in extracts with the following activities (in nmoles min(-1) x (mg of protein) x (-1)): arginine deiminase, 3.30; catabolic ornithine carbamyltransferase (OCT), 1.3; anabolic OCT, 93.0; and carbamate kinase, 1829. The organism metabolized the ornithine produced from catabolic OCT activity to putrescine via ornithine decarboxylase (ODC). The polyamines, spermidine and spermine, were formed by the sequential addition of the aminopropyl group of decarboxylated S-adenosyl-L-methionine (SAM) by the respective polyamine synthases. In addition, asparaginase activity was confirmed in H. inflata, catalysing the deamination of asparagine generating aspartate and ammonia. This study also indicates that, as with other amitochondriate protozoa and some bacteria, the ADH pathway significantly contributes to the energy yield of the cell, particularly under O(2)-limited conditions.

[Sociodemographic factors associated with symptoms of depression in a sample women held at two prisons in Mexico]. / Factores sociodemográficos asociados con los síntomas depresivos en una muestra de mujeres recluidas en dos prisiones de México.

OBJECTIVES: To determine the prevalence of depressive symptoms among a sample of women held in two Mexican prisons and to identify the sociodemographic factors associated with these symptoms. METHODS: An exploratory, descriptive study was conducted of women 18-50 years of age in two prisons in the state of Veracruz, Mexico: the Pacho Viejo (PV) facility and Fortaleza San Carlos (FSC) facility. The Hamilton scale for depressive illness was applied and relationships were found between the participants' scores and their sociodemographic traits (age, marital status, number of children, jail work assignment, and number/frequency of visitors), legal status, type of crime committed, and length of sentence. The analysis employed Student's T test, Chi-squared test, and Student-Newman-Keuls' post hoc test, depending on the variable. RESULTS: All of the women studied at both facilities presented with symptoms of depression. Women at the PV facility had a lower score for depressive symptoms than those at FSC (20.8 +/- 0.8 versus 25.2 +/- 0.9; P <0.001). A higher score was found among women with children than among those without children (25.3 +/- 0.9 versus 21.8 +/- 1.3; P < 0.05); the group of women receiving weekly visits scored (15.0 +/- 1.3) significantly lower than the other groups (F[4.46] = 30.7; P < 0.0001). No significant differences were found to be related to marital status, work assignment, age, type of crime, or the length of sentence. CONCLUSIONS: Symptoms of depression were prevalent among the study sample, and were most powerfully related to having children and infrequent visits. Social adaptation programs should encourage continuous contact between women and their children, family, and friends.

Dependence of Trichomonas vaginalis upon polyamine backconversion.

Trichomonas vaginalis grown for 16 h in the presence of [(14)C]spermine formed a high intracellular pool of [(14)C]spermidine and a small but detectable pool of [(14)C]putrescine. When [(3)H]putrescine was added to the growth medium, a large intracellular pool of [(3)H]putrescine was found, but it was not further metabolized, confirming previous studies suggesting the absence of a forward-directed polyamine synthetic pathway in T. vaginalis. Spermidine:spermineN:(1)-acetyltransferase (SSAT) and polyamine oxidase enzyme activities were detected which collectively converted spermine to spermidine. Polyamine oxidase was localized in the hydrogenosome-enriched fraction, whereas SSAT was found predominantly in the cytosolic fraction. In the presence of saturating substrate, the trichomonad SSAT had an activity of 0. 39+/-0.09 nmol min(-1) (mg protein)(-1) (the mean of five analyses) and an apparent K:(m) for spermine of 1.7 microM. The enzyme was competitively inhibited by di(ethyl)norspermine with a K:(i) of 28 microM. Growth studies indicated that 50 microM di(ethyl)norspermine caused a 68% and 84% reduction in the intracellular concentrations of spermidine and spermine, respectively. The trichomonad polyamine oxidase required FAD as a cofactor and had an apparent K:(m) of 6.0 microM for N(1)-acetylspermine. The potential of bis(alkyl) polyamine analogues as antitrichomonad agents is discussed.

Factores sociodemográficos asociados con los síntomas depresivos en una muestra de mujeres recluidas en dos prisiones de México / Sociodemographic factors associated with symptoms of depression in a sample of women held at two prisons in Mexico

OBJETIVOS: Determinar la frecuencia de los síntomas depresivos en una muestra de mujeres recluidas en dos prisiones mexicanas e identificar los factores sociodemográficos asociados con estos síntomas. MÉTODOS: Se realizó un estudio exploratorio y descriptivo en mujeres de 18 a 50 años de dos prisiones del estado de Veracruz, México: los penales Pacho Viejo (PV) y Fortaleza San Carlos (FSC). Se aplicó la escala de depresión de Hamilton y se relacionó su puntaje con las características sociodemográficas de las participantes (edad, estado marital, número de hijos, actividad laboral dentro del penal y número y frecuencia de visitas que recibía) y su situación jurídica, tipo de delito cometido y tiempo de sentencia. Se utilizaron las pruebas de la t de Student, de la χ2 y la post hoc de Student-Newman-Keuls, según las características de las variables. RESULTADOS: Todas las mujeres estudiadas en ambos penales presentaron síntomas depresivos. Las mujeres de PV tuvieron un puntaje menor de síntomas depresivos que las de FSC (20,8 + 0,8 frente a 25,2 + 0,9; P < 0,001). Se encontró un mayor puntaje de depresión en las mujeres con hijos que en las que no tenían hijos (25,3 + 0,9 frente a 21,8 + 1,3; P < 0,05); el grupo de mujeres que recibía visitas semanalmente presentó un puntaje (15,0 + 1,3) significativamente menor que los grupos restantes (F[4, 46] = 30,7; P < 0,0001). No se encontraron diferencias significativas asociadas con el estatus marital, la situación laboral, la edad, el tipo de delito y el tiempo de sentencia. CONCLUSIÓN: Se encontró una elevada frecuencia de síntomas depresivos en la muestra estudiada; la mayor intensidad se relacionó con tener hijos y recibir visitas con poca frecuencia. Los programas de readaptación social deben fomentar el contacto permanente de estas mujeres con sus hijos, familiares y amigos.

OBJECTIVES: To determine the prevalence of depressive symptoms among a sample of women held in two Mexican prisons and to identify the sociodemographic factors associated with these symptoms. METHODS: An exploratory, descriptive study was conducted of women 18-50 years of age in two prisons in the state of Veracruz, Mexico: the Pacho Viejo (PV) facility and Fortaleza San Carlos (FSC) facility. The Hamilton scale for depressive illness was applied and relationships were found between the participants' scores and their sociodemographic traits (age, marital status, number of children, jail work assignment, and number/frequency of visitors), legal status, type of crime committed, and length of sentence. The analysis employed Student's T test, Chi-squared test, and Student-Newman-Keuls' post hoc test, depending on the variable. RESULTS: All of the women studied at both facilities presented with symptoms of depression. Women at the PV facility had a lower score for depressive symptoms than those at FSC (20.8 + 0.8 versus 25.2 + 0.9; P < 0.001). A higher score was found among women with children than among those without children (25.3 + 0.9 versus 21.8 + 1.3; P < 0.05); the group of women receiving weekly visits scored (15.0 + 1.3) significantly lower than the other groups (F[4.46] = 30.7; P < 0.0001). No significant differences were found to be related to marital status, work assignment, age, type of crime, or the length of sentence. CONCLUSIONS: Symptoms of depression were prevalent among the study sample, and were most powerfully related to having children and infrequent visits. Social adaptation programs should encourage continuous contact between women and their children, family, and friends.