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1.
Phys Rev Lett ; 132(16): 163601, 2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38701452

RESUMEN

We theoretically investigate prospects for the creation of nonclassical spin states in trapped ion arrays by coupling to a squeezed state of the collective motion of the ions. The correlations of the generated spin states can be tailored for quantum-enhanced sensing of global or differential rotations of subensembles of the spins by working with specific vibrational modes of the ion array. We propose a pair of protocols to utilize the generated states and demonstrate their viability even for small systems, while assessing limitations imposed by spin-motion entanglement and technical noise. Our work suggests new opportunities for the preparation of many-body states with tailored correlations for quantum-enhanced metrology in spin-boson systems.

2.
Lett Appl Microbiol ; 72(1): 41-52, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32910828

RESUMEN

The use of rosemary essential oil (RO) and its combination with nisin (RO+N) in preventing the multiplication of Alicyclobacillus acidoterrestris in orange juice was evaluated. The minimum inhibitory and bactericidal concentrations (MIC and MBC) for RO were both 125 µg ml-1 while RO+N displayed a synergistic effect. The use of RO and RO+N at concentrations of 1, 4 and 8× MIC in orange juice for 96 h was evaluated in terms of their sporicidal effectiveness. With regard to the action against A. acidoterrestris spores, RO at 8× MIC was sporostatic, whereas RO+N at 1× MIC was sporicidal. Morphological changes in the structure of the micro-organism after treatment were also observed by microscopy. Furthermore, flow cytometric analysis showed that most cells were damaged or killed after treatment. In general, the antioxidant activity after addition of RO+N decreased with time. The results demonstrate that using the combination of RO and nisin can prevent the A. acidoterrestris growth in orange juice.


Asunto(s)
Alicyclobacillus/crecimiento & desarrollo , Antibacterianos/farmacología , Jugos de Frutas y Vegetales/microbiología , Nisina/farmacología , Aceites Volátiles/farmacología , Rosmarinus/química , Alicyclobacillus/efectos de los fármacos , Citrus sinensis
4.
Nat Med ; 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39215150

RESUMEN

Clonal hematopoiesis, a condition in which acquired somatic mutations in hematopoietic stem cells lead to the outgrowth of a mutant hematopoietic clone, is associated with a higher risk of hematological cancer and a growing list of nonhematological disorders, most notably atherosclerosis and associated cardiovascular disease. However, whether accelerated atherosclerosis is a cause or a consequence of clonal hematopoiesis remains a matter of debate. Some studies support a direct contribution of certain clonal hematopoiesis-related mutations to atherosclerosis via exacerbation of inflammatory responses, whereas others suggest that clonal hematopoiesis is a symptom rather than a cause of atherosclerosis, as atherosclerosis or related traits may accelerate the expansion of mutant hematopoietic clones. Here we combine high-sensitivity DNA sequencing in blood and noninvasive vascular imaging to investigate the interplay between clonal hematopoiesis and atherosclerosis in a longitudinal cohort of healthy middle-aged individuals. We found that the presence of a clonal hematopoiesis-related mutation confers an increased risk of developing de novo femoral atherosclerosis over a 6-year period, whereas neither the presence nor the extent of atherosclerosis affects mutant cell expansion during this timeframe. These findings indicate that clonal hematopoiesis unidirectionally promotes atherosclerosis, which should help translate the growing understanding of this condition into strategies for the prevention of atherosclerotic cardiovascular disease in individuals exhibiting clonal hematopoiesis.

5.
Eur J Clin Microbiol Infect Dis ; 31(10): 2513-27, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22581304

RESUMEN

Candida albicans, C. glabrata, C. parapsilosis, and C. tropicalis are able to form biofilms on virtually any biomaterial implanted in a human host. Biofilms are a primary cause of mortality in immunocompromised and hospitalized patients, as they cause recurrent and invasive candidiasis, which is difficult to eradicate. This is due to the fact that the biofilm cells show high resistance to antifungal treatments and the host defense mechanisms, and exhibit an excellent ability to adhere to biomaterials. Elucidation of the mechanisms of antifungal resistance in Candida biofilms is of unquestionable importance; therefore, this review analyzes both the chemical composition of biomaterials used to fabricate the medical devices, as well as the Candida genes and proteins that confer drug resistance.


Asunto(s)
Antifúngicos/farmacología , Materiales Biocompatibles/farmacología , Biopelículas , Candida/efectos de los fármacos , Candida/crecimiento & desarrollo , Antifúngicos/química , Materiales Biocompatibles/química , Candida/genética , Candida/fisiología , Candidiasis Invasiva/epidemiología , Candidiasis Invasiva/microbiología , Adhesión Celular , Membrana Celular/metabolismo , Farmacorresistencia Fúngica , Fluconazol/farmacología , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Genes Fúngicos , Humanos , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Prótesis e Implantes/microbiología
6.
Int J Clin Pract ; 65(6): 669-73, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21564439

RESUMEN

BACKGROUND: An association between prolactin-secreting pituitary adenomas and anaemia in male patients has been recently reported. Our aim has been to evaluate the prevalence of anaemia in men with prolactinomas and to assess the relationships between haemoglobin concentrations and pituitary function at diagnosis in these patients. METHODS: In a retrospective analysis, 26 male patients with prolactinomas (22 macroprolactinomas and 4 microprolactinomas) were studied. Blood haemoglobin concentration, haematocrit value and baseline hormonal levels were collected at the time of prolactinoma diagnosis. The presence or absence of partial or total hypopituitarism was also evaluated at diagnosis. Logistic regression analysis was used to assess the presence of anaemia as a function of serum hormone concentrations and pituitary dysfunction. RESULTS: Patient bearing macroprolactinomas showed significant lower haemoglobin concentrations than those found in patients with microprolactinomas (13.5 ± 1.2 g/dl vs. 15.1 ± 0.9 g/dl, p < 0.05). Anaemia (haemoglobin < 13 g/dl) was present in nine (34.6%) patients, all of them with macroprolactinomas. The degree of anaemia was mild (haemoglobin > 11 g/dl) in all patients. No correlation between haemoglobin and serum prolactin was found. Haemoglobin concentration was significantly lower in men with hypogonadism (n = 14) than in eugonadal men. Haemoglobin value was also significantly lower in patients with total hypopituitarism in comparison with patients with partial hypopituitarism (12.4 ± 1.0 g/dl, n = 7 vs. 14.0 ± 1.2 g/dl, n = 13, p = 0.007). The number of affected pituitary axes was found to be related with the presence of anaemia. Logistic regression analysis showed that anaemia was related with FT4 (OR 0.23; 95% CI 0.06-0.81, p = 0.02), cortisol (OR 0.81; 95% CI 0.68-0.96, p= 0.02) and the presence of hypopituitarism (OR 20.0; 95% CI 1.68-238.63, p = 0.02). CONCLUSIONS: Anaemia was found in about a third of men with prolactinomas. Our results also suggest that the presence of anaemia in these patients seems to be associated with panhypopituitarism.


Asunto(s)
Anemia/etiología , Neoplasias Hipofisarias/complicaciones , Prolactinoma/complicaciones , Adulto , Hemoglobinas/metabolismo , Humanos , Hipogonadismo/etiología , Hipopituitarismo/etiología , Masculino , Persona de Mediana Edad , Neoplasias Hipofisarias/sangre , Prolactinoma/sangre , Estudios Retrospectivos , Adulto Joven
7.
Sci Adv ; 6(26): eaba7509, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32637615

RESUMEN

Mitochondrial respiratory complexes assemble into supercomplexes (SC). Q-respirasome (III2 + IV) requires the supercomplex assembly factor (SCAF1) protein. The role of this factor in the N-respirasome (I + III2 + IV) and the physiological role of SCs are controversial. Here, we study C57BL/6J mice harboring nonfunctional SCAF1, the full knockout for SCAF1, or the wild-type version of the protein and found that exercise performance is SCAF1 dependent. By combining quantitative data-independent proteomics, 2D Blue native gel electrophoresis, and functional analysis of enriched respirasome fractions, we show that SCAF1 confers structural attachment between III2 and IV within the N-respirasome, increases NADH-dependent respiration, and reduces reactive oxygen species (ROS). Furthermore, the expression of AOX in cells and mice confirms that CI-CIII superassembly segments the CoQ in two pools and modulates CI-NADH oxidative capacity.

8.
Braz J Med Biol Res ; 52(9): e8224, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31482975

RESUMEN

Leishmaniasis is a neglected disease that affects a large part of the world population. Knowing the sand fly fauna of a region is of fundamental importance for guiding health surveillance actions related to the prevention and control of leishmaniasis. A total of 86 specimens of sand flies (60 females and 26 males) were collected. Using the classification proposed by Galati (2003), the following species were identified: Lutzomyia longipalpis (Lutz & Neiva, 1912), Migonemyia migonei (França, 1920), Evandromyia cortelezzi (Brethes, 1923), Ev. sallesi (Galvão & Coutinho, 1939), Nyssomyia whitmani (Atunes & Coutinho, 1939), Psathyromyia lutziana (Costa Lima, 1932), Ev. lenti (Mangabeira, 1938), Brumptomyia sp. (França and Parrot, 1921), and Pressatia sp. (Mangabeira, 1942). Using PCR with internal transcribed spacer target to identify infected sand flies, five Lu. longipalpis females were infected with Leishmania spp. Despite the small number of specimens collected, considerable species diversity was found in the study area.


Asunto(s)
Insectos Vectores/clasificación , Insectos Vectores/parasitología , Leishmania/aislamiento & purificación , Psychodidae/clasificación , Psychodidae/parasitología , Animales , Brasil , ADN Espaciador Ribosómico/genética , Femenino , Leishmania/genética , Leishmaniasis/transmisión , Masculino , Reacción en Cadena de la Polimerasa , ARN Protozoario/genética
9.
Climacteric ; 11(6): 483-8, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18991075

RESUMEN

OBJECTIVE: The objective of this study was to evaluate the effects of raloxifene on the weight and epithelial thickness of the urethra of castrated female rats. METHODS: Forty castrated female rats were randomly separated into two groups: group I (control, n = 20) received only the vehicle, and group II (raloxifene, n = 20) received 750 microg/day of raloxifene for 30 days. On the 31st day, the animals were sacrificed and the urethras were removed for the study. A model for categorical data using the weighted minimum mean square error method and Student's t test were used for the data analysis (p < 0.05). RESULTS: The mean weights of the urethras in groups I and II were 22 +/- 1.6 mg and 24 +/- 1.7 mg, respectively (p = 0.371). There was an increase in the mean epithelial thickness of the distal segments in group II compared to group I (50.7 +/- 1.9 microm vs. 45.3 +/- 1.6 microm, respectively) (p < 0.04). No statistically significant difference was found in the mean epithelial thickness of the proximal urethra between the two groups (p = 0.187). CONCLUSION: Raloxifene administered to castrated female rats for 30 days increased the distal urethral epithelial thickness and did not alter the weight of the urethra.


Asunto(s)
Clorhidrato de Raloxifeno/farmacología , Moduladores Selectivos de los Receptores de Estrógeno/farmacología , Uretra/efectos de los fármacos , Vejiga Urinaria/efectos de los fármacos , Animales , Modelos Animales de Enfermedad , Femenino , Ovariectomía , Posmenopausia/efectos de los fármacos , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Incontinencia Urinaria/prevención & control
10.
Int J Audiol ; 47(3): 115-8, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18307091

RESUMEN

The purpose of this retrospective study is to examine the possible association between iris pigmentation and susceptibility to noise-induced hearing loss in 2407 noise-exposed workers. The workers were between 16 to 65 years of age and were exposed to 2 to 42 years of work-related noise. Results demonstrated that dark-eyed workers presented a greater percentage of normal pure-tone thresholds than fair-eyed workers. Fair-eyed workers had threshold averages of 25.1 dB (right ear) and 26.0 dB (left ear) at 3, 4, and 6 kHz, which were significantly worse than workers with dark irises, with threshold averages of 15.8 dB and 17.2 dB in the right and left ear, respectively (p<0.01). Fair-eyed workers with less than 10 years of noise exposure had the same audiometric pattern as the dark-eyed workers exposed for more than 10 years. Workers not exposed to noise did not present significant differences in their audiometric pattern as a function of eye colour. These results suggest that iris pigmentation may be an additional indication of susceptibility to noise-induced hearing loss.


Asunto(s)
Pérdida Auditiva Provocada por Ruido/etiología , Iris , Epitelio Pigmentado Ocular , Adolescente , Adulto , Anciano , Audiometría de Tonos Puros , Biomarcadores , Estudios Transversales , Susceptibilidad a Enfermedades , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ruido en el Ambiente de Trabajo/efectos adversos , Exposición Profesional/efectos adversos , Estudios Retrospectivos , Factores de Tiempo
12.
Plant Dis ; 102(10): 1965-1972, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30265221

RESUMEN

Big-leaf mahogany (Swietenia macrophylla) is valued for its high-quality wood and use in urban landscapes in Mexico. During surveys of mango-producing areas in the central western region of Mexico, symptoms of malformation, the most important disease of mango in the area, were observed on big-leaf mahogany trees. The objectives of this research were to describe this new disease and determine its cause. Symptoms on big-leaf mahogany at four sites in Michoacán, Mexico resembled those of the vegetative phase of mango malformation, including compact, bunched growth of apical and lateral buds, with greatly shortened internodes and small leaves that curved back toward the supporting stem. Of 163 isolates that were recovered from symptomatic tissues, most were identified as Fusarium pseudocircinatum (n = 121) and F. mexicanum (n = 39) using molecular systematic data; two isolates represented unnamed phylospecies within the F. incarnatum-equiseti species complex (FIESC 20-d and FIESC 37-a) and another was in the F. solani species complex (FSSC 25-m). However, only F. mexicanum and F. pseudocircinatum induced malformation symptoms on 14-day-old seedlings of big-leaf mahogany. The results indicate that F. mexicanum and F. pseudocircinatum, previously reported in Mexico as causal agents of mango malformation disease, also affect big-leaf mahogany. This is the first report of this new disease and the first time that F. mexicanum was shown to affect a host other than mango.


Asunto(s)
Fusarium/aislamiento & purificación , Fusarium/patogenicidad , Meliaceae/microbiología , Enfermedades de las Plantas/microbiología , ADN de Hongos/genética , Fusarium/genética , México , Tipificación de Secuencias Multilocus , Filogenia , Plantones/microbiología
13.
Infect Genet Evol ; 6(5): 361-7, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16461017

RESUMEN

Polymorphism in SLC11A1 has been implicated in host susceptibility to tuberculosis. We have studied associations between INT4, D543N, and 3'UTR polymorphisms of SLC11A1 and different clinical forms of TB. Analysis used 507 patients with pulmonary TB, 123 with extra pulmonary TB and 513 controls. INT4 and D543N showed allelic association with pulmonary TB (P=0.02 and 0.03 respectively). INT4-D543N-3'UTR haplotypes showed an association with pulmonary TB (P=0.03). No association of SLC11A1 with miliary TB was observed, and a possible association of D543N to the pleural form (P=0.08) was suggested. These results support association between SLC11A1 and TB, particularly to the common pulmonary form.


Asunto(s)
Proteínas de Transporte de Catión/genética , Predisposición Genética a la Enfermedad , Polimorfismo Genético , Tuberculosis Pulmonar/genética , Adolescente , Adulto , Genotipo , Haplotipos , Humanos , Masculino , Perú/epidemiología , Tuberculosis Pulmonar/epidemiología
14.
Endocrinology ; 117(6): 2483-9, 1985 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-2415348

RESUMEN

The pattern of alpha MSH release during immobilization stress in ovariectomized rats was determined and correlated with that of plasma PRL and LH. Stress induced a marked elevation in plasma immunoreactive alpha MSH, with a time course identical to that of plasma PRL. The increment in plasma PRL was greater than that in plasma alpha MSH. Plasma LH was markedly lowered by stress. Analysis of pituitary and hypothalamic alpha MSH indicated a significant (P less than 0.05) increase in the neurointermediate lobe and anterior lobe content of alpha MSH. The alpha MSH content in the hypothalamus was lowered by stress when expressed as tissue content (P less than 0.025), although no significant differences in content in this area were detected when the results were expressed in terms of tissue protein. Stress induced a marked increase (P less than 0.01) in the median eminence levels of alpha MSH. Intraventricular (third ventricle) injection of the gamma-globulin fraction of a specific antiserum raised against alpha MSH increased basal PRL levels (P less than 0.025) and prevented the decline in plasma PRL that occurred 60 min after the onset of stress in the normal rabbit serum-injected rats. The stress-induced suppression of plasma LH was attenuated and delayed by the administration of alpha MSH antibodies. In conclusion, alpha MSH of brain origin is released during stress and is involved in lowering plasma PRL to basal levels and producing a partial suppression of plasma LH.


Asunto(s)
Hormona Luteinizante/sangre , Hormonas Estimuladoras de los Melanocitos/sangre , Prolactina/sangre , Estrés Fisiológico/metabolismo , Animales , Femenino , Hipotálamo/análisis , Sueros Inmunes , Inyecciones Intraventriculares , Hormonas Estimuladoras de los Melanocitos/inmunología , Hipófisis/análisis , Ratas , Ratas Endogámicas , Restricción Física , Factores de Tiempo , gammaglobulinas/administración & dosificación , gammaglobulinas/farmacología
15.
Mol Biochem Parasitol ; 52(1): 53-62, 1992 May.
Artículo en Inglés | MEDLINE | ID: mdl-1625707

RESUMEN

Chitinase activity was measured in extracts of Entamoeba invadens cells as a function of time of encystation in axenic conditions using 4-MU(Ch)3 as substrate. Encystment was paralleled by chitinase activity which showed a peak after about 72 h of cultivation where cysts accounted for 63% of cell population. Thereafter, activity fell off rapidly, whereas encystment continued, reaching 80% at the end of the experiment (96 h). Comparison of activity between cysts and the total cell population in 48- and 72-h-old encysting cultures suggested that chitinase may start to accumulate in the pre-cyst forms. About 70% of the enzyme was recovered in the supernatant following low-speed centrifugation of whole extracts. Most of this activity represented soluble chitinase since it was not sedimented by further centrifugation at 105,000 x g. A minor proportion of enzyme activity remained associated to the buffer-washed, high-speed sediment. In addition to 4-MU(Ch)3, chitinase activity was also measured following the hydrolysis of other substrates such as nascent, preformed or colloidal chitin. Like other chitinases, the cyst enzyme preferred nascent over preformed chitin as substrate. Digestion of the former yielded GlcNAc and minor amounts of (GlcNAc)2 as products. Allosamidin strongly inhibited hydrolysis of the fluorogenic substrate by the amebic chitinase in vitro with a Ki of 0.065 microM. IC50 values were 0.085 microM and 0.16 microM at 5 microM and 10 microM 4-MU(Ch)3, respectively. When added to the axenic medium, the drug markedly retarded encystment though it was partially recovered after longer periods of incubation.


Asunto(s)
Acetilglucosamina/análogos & derivados , Quitinasas/metabolismo , Entamoeba/enzimología , Trisacáridos/farmacología , Acetilglucosamina/farmacología , Animales , Quitina/metabolismo , Quitinasas/antagonistas & inhibidores , Entamoeba/crecimiento & desarrollo , Hidrólisis , Cinética , Especificidad por Sustrato
16.
Int J Parasitol ; 23(7): 847-52, 1993 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8314367

RESUMEN

Growth of E. invadens was paralleled by a concomitant increase in ornithine decarboxylase activity which peaked after 5 days of cultivation in TYI-S-33 medium. Over this period, enzyme activity increased about nine-fold with respect to that present at the start of incubation. Thereafter and coinciding with the onset of the stationary growth phase, enzyme activity started to decline reaching trace levels after 8 days of cultivation. Most of the enzyme remained soluble following centrifugation of amoeba homogenates at 105,000 g. alpha-Difluoromethylornithine failed to affect ornithine decarboxylase activity in vitro and amoeba growth. The enzyme was markedly inhibited by polyamines (putrescine, spermidine and spermine) and 1,4-diamino-2-butanone, a putrescine-analog. The latter arrested proliferation of cells, an effect that could not be reversed by polyamines which by themselves also inhibited growth to a low but significant extent. Our results indicate that polyamine biosynthesis from ornithine is required for growth of E. invadens and that this function is rapidly abolished following entry into the stationary growth phase.


Asunto(s)
Entamoeba/enzimología , Ornitina Descarboxilasa/biosíntesis , Animales , Eflornitina/farmacología , Entamoeba/efectos de los fármacos , Entamoeba/crecimiento & desarrollo , Ornitina Descarboxilasa/efectos de los fármacos , Poliaminas/farmacología , p-Dimetilaminoazobenceno/farmacología
17.
Int J Parasitol ; 21(3): 373-5, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-1894436

RESUMEN

A simplified and reliable method to quantify Entamoeba histolytica cytotoxicity was standardized. Mice spleen leucocytes were utilized as target cells. Interaction time was reduced to 1 h by pelleting interacting cells. To assess target-cell killing by amoebae, a nigrosine exclusion test was employed. Fixation with glutaraldehyde stabilized the percentage of stained target cells. Similar results were obtained when cytotoxicity of the E. histolytica HM1 strain was tested by the traditional and proposed methods. The new method allowed quantification of the contribution of cytolysis and cytophagocytosis to amoebic cytotoxicity. It was also demonstrated that uncloned E. histolytica HM1 strain is a heterogeneous population with respect to cytotoxicity expression.


Asunto(s)
Entamoeba histolytica/fisiología , Bazo/parasitología , Animales , Células Cultivadas , Leucocitos/inmunología , Leucocitos/parasitología , Ratones , Fagocitosis , Bazo/citología
18.
Int J Parasitol ; 28(9): 1333-40, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9770617

RESUMEN

Sequential incubation of a mixed membrane fraction isolated from Entamoeba histolytica trophozoites with the nonionic detergents Brij 35 and Igepal CA-630 rendered a soluble fraction with the ability to transfer N-acetylglucosamine (GlcNAc) from UDP-GlcNAc to dolichol phosphate to form a lipid saccharide that was identified as a mixture of dolichol-P-P-GlcNAc and dolichol-P-P-(GlcNAc)2 as follows. (a) The reaction occurred only in the presence of exogenously added dolichol phosphate and was strongly inhibited by tunicamycin and amphomycin; (b) Over 90% of the aminosugar moiety of the lipid saccharide was released by mild acid hydrolysis and was identified as a mixture of GlcNAc and diacetylchitobiose [(GlcNAc)2]; (c) Time course experiments revealed that dolichol-P-P-(GlcNAc)2 accumulated at the expense of a parallel decrease in dolichol-P-P-GlcNAc revealing the tandem operation of UDPGlcNAc:dolichol-P GlcNAc-1-P transferase and UDPGlcNAc:dolichol-P GlcNAc transferase. Mg2+ and to a lower extent Mn2+ were required for catalytic activity and were optimal at 2.5 mM and 1.25 mM, respectively. Common phospholipids with different head groups failed to increase catalytic activity and phosphatidylglycerol was inhibitory. At low concentration, nucleotides such as ATP, GMP and GTP brought about stimulations of 24-54% but higher concentrations were inhibitory. Others were inhibitory at all concentrations the strongest being those containing a uridine base.


Asunto(s)
Acetilglucosamina/metabolismo , Asparagina/metabolismo , Entamoeba histolytica/metabolismo , Glucólisis/fisiología , N-Acetilglucosaminiltransferasas/metabolismo , Oligosacáridos/biosíntesis , Monosacáridos de Poliisoprenil Fosfato/metabolismo , Animales , Antibacterianos/farmacología , Cationes Bivalentes/administración & dosificación , Cromatografía en Papel , Fosfatos de Dolicol/metabolismo , Lipopéptidos , Magnesio/administración & dosificación , Manganeso/administración & dosificación , Lípidos de la Membrana/metabolismo , Proteínas de la Membrana/metabolismo , Oligopéptidos/farmacología , Polidocanol , Polietilenglicoles/metabolismo , Tensoactivos/metabolismo , Factores de Tiempo , Tunicamicina/farmacología
19.
Int J Parasitol ; 26(3): 253-60, 1996 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8786214

RESUMEN

Multiplication of E. histolytica was accompanied by a parallel increase in ornithine decarboxylase (ODC) specific activity up to 72 h of cultivation in TYI-S-33 medium. Thereafter, activity rapidly decayed whereas growth continued for another 24 h before entering into the stationary growth phase. ODC was very unstable. Partial purification (14-fold) of the enzyme was achieved by a three-step procedure involving high-speed centrifugation, gel filtration and adsorption to hydroxylapatite. The partially purified enzyme (Mr 211 kDa) revealed maximum activity at pH 8.5-9.0 and a sigmoidal response to substrate concentration. An S0.5 value of 1.0 mM ornithine was estimated. Although ODC did not exhibit an absolute dependence on pyridoxal phosphate (PLP), addition of PLP increased catalytic activity about 4-fold, with an S0.5 value of 45 microM. Evolution of 14CO2 from ornithine was markedly inhibited by polyamines in the following increasing order of effectiveness: putrescine > spermidine > spermine. The substrate analogs alpha-methylornithine and alpha-difluoromethylornithine had no effect on enzyme activity and cell growth. In contrast, 1,3-diaminopropane and 2,4-diamino-2-butanone, 2 putrescine analogs, severely inhibited both enzyme activity and amoeba multiplication. Results are discussed in terms of the role of ODC in the amoeba proliferation.


Asunto(s)
Entamoeba histolytica/enzimología , Ornitina Descarboxilasa/metabolismo , Proteínas Protozoarias/metabolismo , Animales , División Celular , Ornitina Descarboxilasa/aislamiento & purificación , Inhibidores de la Ornitina Descarboxilasa , Proteínas Protozoarias/antagonistas & inhibidores , Proteínas Protozoarias/aislamiento & purificación , Putrescina/farmacología , Espermidina/farmacología , Espermina/farmacología
20.
Peptides ; 6(3): 503-8, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-4070018

RESUMEN

Circulating levels and tissue content of alpha-MSH were measured on the morning of various days of the estrous cycle, and on the afternoon of proestrus in freely moving conscious rats. No surges of alpha-MSH were detected by RIA in the morning of various days of the cycle. The neurointermediate lobe content of alpha-MSH was slightly elevated on diestrus 1 as compared to the levels on diestrus 11 and proestrus but not to estrous levels. No changes in alpha-MSH content were detected in the anterior pituitary, the median eminence, mediobasal hypothalamus and the preoptic area at various stages of the estrous cycle. Plasma alpha-MSH levels were slightly elevated at 1500 hr of proestrus which was followed three hours later by a decline. This profile of plasma alpha-MSH on the afternoon of proestrus was reproduced by the SC administration of estradiol benzoate to long-term ovariectomized rats. These data suggest that, contrary to the results obtained by bioassay of alpha-MSH no surges of alpha-MSH occur on any day of the cycle, although a slight elevation on the afternoon of proestrus was detected. The altered pattern of release of this peptide on the afternoon of proestrus may be induced by estrogen.


Asunto(s)
Estradiol/farmacología , Estro , Hormonas Estimuladoras de los Melanocitos/metabolismo , Animales , Femenino , Hipotálamo Medio/metabolismo , Hormona Luteinizante/sangre , Eminencia Media/metabolismo , Hormonas Estimuladoras de los Melanocitos/sangre , Ovariectomía , Hipófisis/metabolismo , Adenohipófisis/metabolismo , Área Preóptica/metabolismo , Prolactina/sangre , Ratas , Núcleo Supraquiasmático/metabolismo
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