The specific features of methionine biosynthesis and metabolism in plants

Plants, unlike other higher eukaryotes, possess all the necessary enzymatic equipment for de novo synthesis of methionine, an amino acid that supports additional roles than simply serving as a building block for protein synthesis. This is because methionine is the immediate precursor of S-adenosylmethionine (AdoMet), which plays numerous roles of being the major methyl-group donor in transmethylation reactions and an intermediate in the biosynthesis of polyamines and of the phytohormone ethylene. In addition, AdoMet has regulatory function in plants behaving as an allosteric activator of threonine synthase. Among the AdoMet-dependent reactions occurring in plants, methylation of cytosine residues in DNA has raised recent interest because impediment of this function alters plant morphology and induces homeotic alterations in flower organs. Also, AdoMet metabolism seems somehow implicated in plant growth via an as yet fully understood link with plant-growth hormones such as cytokinins and auxin and in plant pathogen interactions. Because of this central role in cellular metabolism, a precise knowledge of the biosynthetic pathways that are responsible for homeostatic regulation of methionine and AdoMet in plants has practical implications, particularly in herbicide design.     

Cavernous haemangioma of the iris in a leprosy patient

We report a case of a male infant who presented with congenital anomalies and was found to have a de novo deletion in the terminal region of the long arm of chromosome 9. He died at the age of 17 weeks of cardiorespiratory failure owing to RSV positive bronchiolitis. A review of previously published reports documented one previous report of a patient with a deletion of (9)(q34.3) and multiple congenital anomalies. Comparison with the previously reported case suggests that the phenotype observed constitutes a clinically recognisable pattern of malformations.     

An investigation of late closure: The role of syntax, thematic structure, and pragmatics in initial interpretation.

Four reading-time experiments investigated the application of the late closure principle in Italian. The experiments tested the principle governing the initial attachment of different types of modifiers (relative clause, adjectival phrase, and prepositional phrase) to a complex noun phrase. By manipulating the type of preposition within the complex noun phrase, the authors investigated the role of the thematic structure in initial and final parsing. The results show that the late closure principle applies to initial parsing in Italian without being affected by the thematic structure of the complex noun phrase. Final interpretation, however, shows an effect of pragmatic preference and an effect of thematic structure on syntactic revisions. The results are discussed in terms of a parsing model that adopts syntactic parsing strategies and makes modular use of linguistic information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition of adenosine deaminase by erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) mimics the effect of inescapable shock on escape learning in rats.

Three experiments examined the role of adenosine neuroregulation in the production of shuttle-escape deficits caused by prior exposure to inescapable electric shock in rats (learned helplessness). Intracerebroventricular administration of erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), a selective adenosine deaminase inhibitor, mimicked the effect of earlier inescapable shock at a dose of 2.5 μM in previously restrained rats. Performance deficits produced by EHNA or by earlier exposure to inescapable shock were reversed by intraperitoneal injection of 10 mg/kg caffeine, an adenosine receptor antagonist. Finally, preexposure to an ineffective number of shocks interacted in synergy with an ineffective pretest dose (1.0 μM) of EHNA to maximize shuttle-escape latencies. These data implicate endogenous adenosine neuroregulation as a proximate mechanism in learned helplessness and conservation-withdrawal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infantile and juvenile hypothyroidism with the gland in place and low radio-iodide uptake

27 hypothyroid infants of children, with a low iodine uptake in spite of a thyroid gland or thyroid tissue in normal pretracheal place, have been studied. 21 cases are related to primary thyroid involvement leading to vanishing iodine or technetium uptake. In 8 of these cases, clinical onset in late childhood, high frequency of antithyroid antibodies and of familial thyroid dysfunction were similar to those found in childhood's thyroiditis. 8 other cases had a precocious onset (first months in 6, first year in 1, second year in 1) with some pretracheal iodine uptake when first studied and no uptake at further examinations, 1 patient having received no treatment from first to second study, the others being without treatment from more than two months and certain of them receiving injections of TSH. The last 5 cases of this group were those of children born to 2 mothers with treated hypothyroidism, with low iodine uptake in pretracheal place. The role of genetic factors and auto-immunity in theses cases is discussed. The 6 other patients had clinically isolated hypothyroidism secondary to TSH deficiency, eventually associated to clinically inapparent GH or ACTH deficiencies, most of them by hypothalamic defect with normal response to TRH.     

Phase transition in poly(vinylidene fluoride) investigated with micro-Raman spectroscopy

The phase transition from the non-polar alpha-phase to the polar beta-phase of poly(vinylidene fluoride) (PVDF) has been investigated using micro-Raman spectroscopy, which is advantageous because it is a nondestructive technique. Films of alpha-PVDF were subjected to stretching under controlled rates at 80 degrees C, while the transition to beta-PVDF was monitored by the decrease in the Raman band at 794 cm(-1) characteristic of the alpha-phase, along with the concomitant increase in the 839 cm(-1) band characteristic of the beta-phase. The alpha-->beta transition in our PVDF samples could be achieved even for the sample stretched to twice (2x-stretched) the initial length and it did not depend on the stretching rate in the range between 2.0 and 7.0 mm/min. These conclusions were corroborated by differential scanning calorimetry (DSC) and X-ray diffraction experiments for PVDF samples processed under the same conditions as in the Raman scattering measurements. Poling with negative corona discharge was found to affect the alpha-PVDF morphology, improving the Raman bands related to this crystalline phase. This effect is minimized for films stretched to higher ratios. Significantly, corona-induced effects could not be observed with the other experimental techniques, i.e., X-ray diffraction and infrared spectroscopy.     

The comprehensive in vitro evaluation of eight different calcium phosphates: Significant parameters for cell behavior

Eight different calcium phosphate nanoparticles, namely bovine bone bioapatite calcined at 500, 600, and 700°C, Mg-doped brushite, fluorinated calcium phosphate, Ca-deficient hydroxyapatite, hydroxyapatite, and tricalcium phosphate, were characterized employing physico-chemical methods. Their cytocompatibility was evaluated under human osteoblast-like cell line MG-63 culture conditions in elution media and via the direct interaction of cells with calcium phosphate nanoparticles. The main objective was to determine the correlation of the cell indices with the differently determined physical and chemical parameters of the calcium phosphates. Chemical composition, which contributes toward pH changes, and the calcium ion concentration in the medium appear to make up particularly significant factors; moreover, it was proved that the number of material types represents a further important aspect. In the case of a large number of material types, almost no correlation was determined between the analyzed parameters; however, in the case of a small number of apatite types, several positive correlations were found. It can be concluded that it is not possible to identify any monitored parameters that had a major impact on cell behavior or, at least, such an effect which can be generalized. It appears more likely that cell behavior is affected by the interplay of various parameters.