Effect of plant development (age and size) on the Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci.

Whitefly, Bemisia tabaci, is one of the most important pests of tomato, Solanum lycopersicum L. The Mi-1 gene mediates tomato resistance to the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) species of B. tabaci, three species of root-knot nematodes, Meloidogyne spp., and the potato aphid, Macrosiphum euphorbiae. Tomato seedlings bearing the Mi-1 gene are resistant to nematodes soon after germination but resistance to aphids is developmentally regulated; a reliable conclusion about Mi-1 resistance to B. tabaci was not available to date. In the present work, 3-, 5- and 8-week-old plants of the tomato cultivars Motelle and Moneymaker (bearing and lacking the Mi-1 gene, respectively) were simultaneously tested under free-choice (antixenosis) and no-choice (antibiosis) conditions, to assess the real influence of plant age on the Mi-1-mediated resistance to the MED species of B. tabaci. Subsequently, plants of the same age but with different level of development were compared to check whether the plant size can also affect this tomato resistance. Obtained results demonstrated that Mi-1-mediated resistance to B. tabaci is developmentally regulated, as variations in the age of bearing-Mi-1 plants affects most infestation parameters tested. Differences between cultivars with and without the Mi-1 gene were significant for 8- but not for 3-week-old plants. For 5-week-old plants, differences between cultivars were less pronounced than in older plants, expressing an intermediate level of resistance in Motelle. Plant size also influenced whitefly infestation and reproductive activity on the resistant cultivar. However, plant age has more impact than plant size on the Mi-1-mediated resistance of tomato to B. tabaci.

Sall2 is required for proapoptotic Noxa expression and genotoxic stress-induced apoptosis by doxorubicin.

The Sall2 transcription factor is deregulated in several cancers; however, little is known about its cellular functions, including its target genes. Recently, we demonstrated that p53 directly regulates Sall2 expression under genotoxic stress. Here, we investigated the role of Sall2 in the context of cellular response to genotoxic stress. In addition, we further examined the Sall2-p53 relationship during genotoxic stress in primary mouse embryo fibroblasts (MEFs), which are derived from Sall2 knockout mice separately, or in combination with the p53ERTAM knock-in mice. We found that the levels of Sall2 mRNA and protein are dynamically modulated in response to doxorubicin. At early times of stress, Sall2 is downregulated, but increases under extension of the stress in a p53-independent manner. Based on caspase-3/7 activities, expression of cleaved poly (ADP-ribose) polymerase, expression of cleaved caspase-3 and induction of proapoptotic proteins, Sall2 expression was correlated with cellular apoptosis. Consequently, Sall2-/- MEFs have decreased apoptosis, which relates with increased cell viability in response to doxorubicin. Importantly, Sall2 was required for apoptosis even in the presence of fully activated p53. Searching for putative Sall2 targets that could mediate its role in apoptosis, we identified proapoptotic NOXA/PMAIP1 (phorbol-12-myristate-13-acetate-induced protein 1). We demonstrated that Sall2 positively regulates Noxa promoter activity. Conserved putative Sall2-binding sites at the NOXA promoter were validated in vitro by electrophoretic mobility shift assay and in vivo by ChIP experiments, identifying NOXA as a novel Sall2 target. In agreement, induction of Noxa protein and mRNA in response to doxorubicin was significantly decreased in Sall2-/- MEFs. In addition, studies in leukemia Jurkat T cells support the existence of the Sall2/Noxa axis, and the significance of this axis on the apoptotic response to doxorubicin in cancer cells. Our study highlights the relevance of Sall2 in the apoptotic response to extended genotoxic stress, which is important for understanding its role in normal physiology and disease.

Salicylic acid is required for Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci, but not for basal defense to this insect pest.

Plant defense to pests or pathogens involves global changes in gene expression mediated by multiple signaling pathways. A role for the salicylic acid (SA) signaling pathway in Mi-1-mediated resistance of tomato (Solanum lycopersicum) to aphids was previously identified and its implication in the resistance to root-knot nematodes is controversial, but the importance of SA in basal and Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci had not been determined. SA levels were measured before and after B. tabaci infestation in susceptible and resistant Mi-1-containing tomatoes, and in plants with the NahG bacterial transgene. Tomato plants of the same genotypes were also screened with B. tabaci (MEAM1 and MED species, before known as B and Q biotypes, respectively). The SA content in all tomato genotypes transiently increased after infestation with B. tabaci albeit at variable levels. Whitefly fecundity or infestation rates on susceptible Moneymaker were not significantly affected by the expression of NahG gene, but the Mi-1-mediated resistance to B. tabaci was lost in VFN NahG plants. Results indicated that whiteflies induce both SA and jasmonic acid accumulation in tomato. However, SA has no role in basal defense of tomato against B. tabaci. In contrast, SA is an important component of the Mi-1-mediated resistance to B. tabaci in tomato.

Parálisis de las cuerdas vocales como presentación inicial de una miastenia grave / Paralysis of the vocal cords as the presenting symptom of myasthenia gravis

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[Respiratory stridency by larynx paralysis. Anusual beginning of miastenia]. / Estridor respiratorio por parálisis laríngea. Debut inusual de miastenia gravis.

A case of severe miastenia beginning with dyspnea, secondary to a bilateral larynx paralysis in aduction is presented. During the evolution of the severe miastenia the affectation of the larynx musculature does not result infrequent, but however, after having realized a bibliographic revision, the infrequency resulting in this disease of the beginning through a bilateral larynx paralysis in aduction was verified. A wide exposition of the clinic case, methods of exploration to obtain the diagnosis of severe miastenia, and the different treatment options actually in use to control these disease, are realized.

Influence of the polymeric morphology of sorbents on their properties in affinity chromatography.

The influence of the polymeric morphology of different types of Fe(3+)-containing sorbents and their properties in retention of phosphoamino acids is presented in this paper. Poly(hydroxylated polybutadienic-hydroxyethyl methacrylate) [poly(PB-HEMA)] and poly(ethylene glycol dimethacrylate-hydroxyethyl methacrylate) [poly(EGDMA-HEMA)] base supports were submitted to chemical modifications to attain metal ion-containing sorbents. Properties such as specific surface area, pore volume, equilibrium volume swelling ratios, extent of conversion rate of functional groups, amount of chelated metal ion, ligand occupation, as well as quantity of phosphoamino acid retained, were used as comparative parameters for those different base matrices. Results suggest that Fe(3+) immobilized on poly(EGDMA-HEMA) base support are more efficient as a group-specific sorbent to retain phosphoamino acids than those obtained using poly(PB-HEMA) base support.

A novel activity for a group of sesquiterpene lactones: inhibition of aromatase.

A group of eleven sesquiterpene lactones isolated from different Asteraceae species from north-western Argentina were investigated for their inhibitory action on the estrogen biosynthesis. Seven of them, of different skeleton types, were found to inhibit the aromatase enzyme activity in human placental microsomes, showing IC50 values ranging from 7 to 110 microM. The most active were the guaianolides 10-epi-8-deoxycumambrin B (compound 1), dehydroleucodin (compound 2) and ludartin (compound 3). These compounds were competitive inhibitors with an apparent Ki = 4 microM, Ki = 21 microM and Ki = 23 microM, respectively. Compounds 1 and 2 acted as type II ligands to the heme iron present in the active site of aromatase cytochrome P450 (P450arom). Besides, all of them failed to affect the cholesterol side-chain cleavage enzyme activity on human placental mitochondrias. This is the first report on the aromatase inhibitory activity of this group of natural compounds.

Topography of human placental 3 beta-hydroxysteroid dehydrogenase/delta 5-4 isomerase in microsomal membrane. A study using limited proteolysis and immunoblotting.

The membrane-bound enzyme 3 beta-hydroxysteroid dehydrogenase delta 5-4 isomerase (3 beta-HSD) catalyzes the formation of delta 4-3-ketosteroids from delta 5-3 beta-hydroxysteroids in placental, adrenal, testicular and ovarian tissues. In the present study was investigated the transverse-plane topography of 3 beta-HSD within the human placental microsome membranes employing immune-replica analysis in combination with surface specific proteolysis. The crucial domains of the enzyme for the dehydrogenase and isomerase reactions are inactivated by proteinase treatments under conditions where latency of hexose-6-phosphate dehydrogenase was 95%. The data indicate that these crucial domains face the cytosolic side of the endoplasmic reticulum membrane. Incubation of the intact microsomes with trypsin produces several immune reactive fragments ranging from 29 to 11 kDa in addition to 42 kDa native enzyme, one of them being shielded by the membrane structure and/or by other intrinsic and peripheral membrane proteins. Carboxypeptidase Y degraded the C terminus of the 42 kDa native 3 beta-HSD in intact and detergent-disrupted microsomes, preserving partially a fragment of 31 kDa. The results from the carboxypeptidase Y digestion indicate that the carboxy terminal end of the 3 beta-HSD enzyme is located on the cytoplasmic surface of the endoplasmic reticulum and that only a small fragment of approx. 11 kDa could be removed easily without affecting the enzyme activity. From these data and the predicted hydropathy analysis from the literature, we tried to assign a transmembrane arrangement to the human placental 3 beta-HSD. Our results support a topology model in which practically all the structural 3 beta-HSD enzyme is exposed to the cytoplasmic side of the membrane with one NH2-terminal-anchoring segment and all the 3 beta-HSD enzyme activity facing to the cytoplasmic side within the 31 kDa NH2-terminal peptide.

Low aromatase activity in microsomes from complete hydatidiform mole.

The complete hydatidiform mole (CHM) is characterized by the presence of aberrant placenta, with hyperplasia of cyto- and syncytiotrophoblasts and the absence of maternal genetic information. Steroidogenesis in this condition is, thus, of special interest. In this study we investigated the kinetic parameters of aromatase in microsomes from CHM compared with those in normal early placenta (NEP). The enzyme activity was determined by measuring the conversion of [3H] testosterone to [3H]estradiol plus [3H]estrone. The Km value for testosterone was 33 nmol/L in CHM and 17 nmol/L in NEP of similar gestational ages. Aminoglutethimide, a nonsteroidal inhibitor, decreased in a dose-dependent manner and with the same potency the aromatization of testosterone in both tissues (ID50, 2 vs. 1 mumol/L in CHM and NEP, respectively). These results suggest that the enzymes from the two sources are kinetically similar. However, the enzyme efficiency, expressed as the maximum velocity/Km ratio, was 17-fold lower in CHM than in NEP tissue (1.22/33 vs. 10.68/17 min/mg.mL). These findings suggest that in molar pregnancy the decreased capacity of trophoblast tissue for the formation of estrogen could increase the testosterone concentration inside the molar vesicle, which, in turn, as we previously reported, inhibits progesterone formation. All of these data could provide an explanation for the low circulating level of progesterone, which may directly or indirectly affect the spontaneous expulsion of this aberrant tissue in the second trimester of pregnancy.

[Hypersensitivity syndrome caused by allopurinol: report of 2 cases and review of the literature]. / Síndrome de hipersensibilidad por alopurinol: a propósito de dos casos y revisión de la literatura.

A severe adverse drug effect secondary to allopurinol ingestion has been described, characterized by fever, eosinophilia, cutaneous rash, hepatic lesion and renal failure, with a high mortality (21-26%) and unknown ethiopathogenicity. In many cases patients had a previous disorder on their renal function (53%) and more than half received allopurinol due to asymptomatic hyperuricemia. We present two new cases and review other 18 patients diagnosed in the last nine years, analyzing the ethiopathogenicity, epidemiological, clinical, therapeutical and preventive aspects.

[Nontraumatic cerebral hematoma in young adults: a study of 42 cases]. / Hematoma intracerebral no traumático en adultos jóvenes: estudio de 42 casos.

BACKGROUND: Cerebrovascular disease has particular features in young adults (15-45 years). In this context, non-traumatic intracranial hematoma (NTICH) has received little attention. Therefore, its analysis has been attempted focusing on etiology, localization and short term prognosis. METHODS: 42 patients aged 15-45 years who were admitted because of NTICH were evaluated. 41 variables were analyzed with chi-square method and Fischer's exact test. RESULTS: The localization of hematoma was as follows: basal ganglia/thalamus in 59%, lobar in 19%, posterior fossa in 12%, pure intraventricular in 2 cases and multiple in one case. The most common etiology was hypertension (HT) (32%), followed by arteriovenous malformations (12%), oral anticoagulants (10%), chronic alcohol abuse (10%), coagulation disorders and one central nervous system arteriopathy; 12 cases were idiopathic. On the basis of etiology two groups were distinguished: 15-30 years (no case with hypertension) and 30-45 years (HT as the leading cause). Survival was 89%. CONCLUSIONS: NTICH in young adults has a heterogeneous etiology. On the basis of the most common cause two groups can be considered: from 15 to 30 years (arteriovenous malformation) and from 30 to 45 years (HT). High blood pressure at the time of stroke is correlated with previous HT. The short term life prognosis is better than that of NTICH in general series. Deterioration of consciousness in the acute phase and oral anticoagulation are poor prognostic factors.