Spontaneous and induced apoptosis in embryogenic cell cultures of carrot (Daucus carota L.) in different physiological states.

Programmed cell death (apoptosis) in plants - and plant cells in culture - has received much less attention than its animal counterpart. In the present work, using agents producing biotic or abiotic stress on cultivated cells from carrot - and, in a few experiments, Arabidopsis -, we show that DNA fragmentation, random or oligonucleosomal, can be induced by different treatments. Moreover, we demonstrate that the same cultures may or may not respond to the inducing signal according to their physiological state. In particular, stationary cells are more responsive to the inducing signal than actively proliferating ones, and cells growing in an unorganized way are more responsive than cells carrying out the embryogenic programme. Senescent cells in culture also appear to die by apoptosis, but healthy cells can also be induced to die apoptotically if exposed to the medium conditioned by senescent cells of the same or different species.

The person who outperforms me is a genius: maintaining perceived competence in upward social comparison.

People have many ways of protecting themselves against unfavorable social comparisons. Sometimes, however, the unfavorableness of a comparison is too unambiguous to deny. In such circumstances, people may indirectly protect their self-images by exaggerating the ability of those who outperform them. Aggrandizing the outperformer is conceived to be a construal mechanism that permits inferior performers to deflect the self-esteem threat of being outperformed while maintaining believability. The tendency to exaggerate an outperformer's ability was demonstrated in a context in which subjects learned they had been outperformed by a confederate on a perceptual intelligence test. Subjects' and observers' ratings of the confederate's intelligence showed that subjects consistently rated the confederate more favorably than did observers. Using a similar methodology in which subjects outperformed confederates, another study showed that subjects exaggerated the ability of the people they outperformed. The conditions in which these effects are most likely to be obtained are discussed.

The secretory nature of the lesion of carrot cell variant ts11, rescuable by endochitinase.

The carrot cell variant ts11 is unable to form somatic embryos at the non-permissive temperature of 32 degrees C, but the block can be overcome by the addition of a 32-kDa acidic endochitinase to the medium. In this work we conducted a cyto-histological analysis of the blocked embryo forms. The morphology of the endomembrane system is altered; in particular, the ER is dilated and may show electron-dense precipitates and continuity with the plasma membrane. These morphological alterations do not occur in the presence of externally-added endochitinase. We also noticed modifications of the culture medium that are probably related to the morphological observations: the total amount of secreted proteins is reduced and pulse-chase experiments revealed that, compared with wild-type cells, the secretion of major polypeptides is reduced while new minor polypeptides are secreted. Western blot analysis revealed the presence of the binding protein BiP, a resident of the ER and of glutamine synthase, a cytosolic protein, in the medium of ts11 but not wild-type cells. These results indicate that ts11 is altered in the secretory pathway but do not clarify the role of endochitinase.

Ionic transport in the plasma membrane of carrot protoplasts from embryogenic cell-suspension cultures.

Ionic transport properties of protoplasts obtained from embryogenic carrot suspension cells were studied by the patch-clamp technique. In the whole-cell configuration, carrot protoplasts presented macroscopic time-dependent outward currents, showing kinetics of activation which did not depend appreciably on the amplitude of the stimulus. Time- and voltage-dependent whole-cell inward rectifying currents as well as instantaneous non-selective currents were also observed. Both time-dependent inward and outward currents are carried by potassium ions. In a cell-attached configuration, two types of single-channel signals, displaying conductances of 10 and 17 pS, were observed; the instantaneous 10 pS channel was also present in outside-out excised patches.

Influence of imaging ability on word transformation.

In the present study, we examined whether individual differences in imaging ability affect visual word recognition. Poor and vivid imagers performed a naming task that involved nonreversed (e.g., JUMP) and reversed (e.g., PMUJ) words (Experiment 1). Poor and vivid imagers were also tested on a naming task that was controlled for verbal ability; all the words were reversed and presentation time was varied (Experiment 2). In both experiments, imaging ability interacted with task difficulty, suggesting that individual differences in imaging ability affect visual word recognition. Specifically, the present data suggest that poor imagers may be less efficient than vivid imagers at processing words analytically. The data are interpreted within a limited-capacity, hybrid, word recognition model, in which words can be processed as either word-level or letter-level codes.

Acute primary meningoencephalitis from entamoeba Naegleria Fowleri. Report of a clinical case with a favourable outcome.

The Authors describe a primary amoebic acute meningoencephalitis case from Naegleria Fowleri, where the parasite was found in the cerebrospinal fluid and in culture. The case had a favorable outcome after treatment with amphotericin B.

Acute meningitis from Cryptococcus neoformans (Filobasidiella neoformans) in a patient suffering from AIDS. Report of a clinical case with a favourable outcome.

The Authors describe a case of acute meningitis from Cryptococcus neoformans, with the finding of the fungus in the cerebrospinal fluid and in culture in a young subject with AIDS. The case had a favourable outcome after fluconazole treatment.

Urticarioid manifestation in course of cerebral imported malaria.

The authors report a case of urticarioid manifestation in a patient with imported pernicious cerebral malaria. They discuss the pathogenetic mechanisms of the cutaneous manifestation and point out the clinical importance of their observation.

Modulation of auxin-binding proteins in cell suspensions : I. Differential responses of carrot embryo cultures.

This paper shows that the level of 2,4-dichlorophenoxyacetic acid (2,4-D) in the medium determines the level of auxin-binding proteins in the membranes of carrot, Daucus carota, cells grown in suspension. This induction takes slightly more than 2 hours to complete and can be elicited by natural as well as synthetic auxins. The auxin binding sites thus generated, which are pronase-sensitive, bind 2,4-D, indoleacetic acid, and naphthalene-acetic acid (NAA) equally well. However both alpha- and beta-NAA bind, whereas only alpha-NAA is effective in the inductive process. Cells committed to embryogeny (proembryogenic masses) do not respond to auxin, i.e. their level of auxin-binding proteins remains very low, and they do not seem to synthesize the hormone, as indicated by inhibitor studies. Sensitivity to, and production of, auxin, begins when the embryo becomes polarized, i.e. at postglobular stage.

[C. pylori colonization of the mucosa in patients with chronic ulcerative and non-ulcerative gastropathies]. / La colonizzazione di C. pylori nella mucosa di soggetti con gastropatie croniche ulcerose e non.

C. pyloridis colonization was investigated in a selected group of 58 patients with upper gastrointestinal disorders submitted to endoscopy and biopsy. The following results were registered. C. pyloridis was isolated in 14 out of 18 cases of active chronic gastritis, in 15 out of 24 cases of non active chronic gastritis, and 7 out of 8 cases of antral ulceration. A negative finding was registered in 8 patients whose gastric mucosa was normal. Therefore, the Authors consider as valid the etiopathogenetic correlation between C. pyloridis and ulcerative or non-ulcerative chronic gastric diseases, suggested by others.

DNA methylation of embryogenic carrot cell cultures and its variations as caused by mutation, differentiation, hormones and hypomethylating drugs.

The level of auxin - both natural and synthetic - in the medium has a strong effect on the level of 5-methyl-cytosine in the DNA of carrot cells in culture. This level may vary from approximately 15% to 70% of total cytosine without apparent effects on growth rate and cell morphology. No effect was seen with cytokinin. During somatic embryogenesis, in the absence of hormones, variations were seen in the level of methylation according to a characteristic pattern. If hypomethylation is induced with drugs such as azacytidine, ethionine or ethoxy-carbonyl-pyrimidine, embryogenesis is immediately blocked. A mutant was isolated which is resistant to the action of hypomethylating drugs. It shows variations in the methylation pattern and variations in indole-acetic acid metabolism. In addition its regeneration is often associated with the production of tumors.

Ethanol production and toxicity in suspension-cultured carrot cells and embryos.

The process of carrot (Daucus carota L.) somatic embryogenesis is highly sensitive to exogenously added ethanol, since 5 mM ethanol inhibits this process by 50%, whereas the growth of proliferating carrot cells is inhibited to the same extent by 20 mM ethanol. This is consistent with the fact that proliferating cultures produce ethanol and release it into the medium at concentrations up to 20 mM, whereas embryogenic culture medium contains less than 1 mM ethanol. Data are presented showing the influence of cell density and 2,4-dichlorophenoxyacetic acid on ethanol production and on the presence of an alcohol-dehydrogenase (EC 1.1.1.1.) inactivator in carrot embryos.

Medicago cell variants showing altered nitrogen utilization.

Nineteen chlorate-resistant variants were isolated after mutagenesis from cells of Medicago coerulea. The level of nitrate reductase activity was variable in these lines and ranged from 100% to less than 5% of the wild type level. Xanthine dehydrogenase was not affected in any of those variants tested.Methylammonium-resistant variants were also isolated from the same type of cells. They show a different regulation of nitrogen utilization. In particular, the enzymatic level of nitrate reductase which, in wild type cells, is sensitive to ammonium repression, is much less affected in the variants. Differences were also seen in the regulation of other functions of the nitrogen-utilizing pathway: xanthine dehydrogenase and, possibly, adenine uptake.

[L forms of Staphylococcus aureus. Behavior of coagulase, hemolytic and desoxyribonuclease activities and antibiotic sensitivity]. / Sulle forme L di Staphylococcus aureus. Comportamento delle attivita coagulasica, emolitica e desossiribonucleasica, e dell'antibiotico-sensibilita'.

L Forms derived from strains of coagulase positive Staphylococcus aureus, have, on the whole, preserved their DNAsic, haemolitic and coagulastic activities. L. forms showed high resistence to antibiotics acting on the bacterial cell-wall. The sensibility to other antibiotics was, roughly, analogous for the L forms as well as for the bacterial strains ones, with the exception of the clortetraciclin and the diidrostreptomicin, ehich proved to be comparatively more active on the L forms.

[Biochemical, enzymatic and cultural characteristics and criteria of pathogenicity of staphylocci (study of strains isolated in a hospital environment)]. / Caratteri biochimici, enzimatici e colturali e criteri di pathogenicita degli stafilococchi (Studio di 200 ceppi isolati in ambiente ospedaliero).

The Authors have examined the coagulase activity, mannitol fermentation, DNase and phosphatase activity, and production of haemolisins and pigment on 200 strains of Staphylococcus isolated from hospitalized patients affected by various diseases. On the basis of results obtained, they conclude that the evaluation of the pathogenic power of Stah. aureus should be always founded upon a "pattern" of biochemical, enzymatic, cultural and toxinogenetic tests.