The key role of residue 5 in angiotensin II

The conformation–biological activity relationships in a series of angiotensin II analogs substituted in position 5 were studied. Results indicated that only analogs with β-branched residue in position 5 possess spectral and biological properties identical to that of parent angiotensin II.     

Bioconversion of substituted naphthalenes to the corresponding salicylic acids

The Pseudomonas fluorescens N3 was isolated from soil for its ability to utilize naphthalene as a carbon source. The strain transforms 2,3-dimethyl-, 2-methoxy-, 1- and 2-ethylnaphthalenes to the corresponding salicylic acids competitively with chemical synthesis. The identification of 2-hydroxy-2-carboxy-7-ethylchromane by biotransformation of 2-ethylnaphthalene, contributes to elucidating the steps involved in the catabolic pathways of naphthalenes to salicylaldehydes. Correspondence to: F. Pelizzoni     

Membrane fluidity of microsomal and thymocyte membranes after X-ray and UV irradiation

A brief literature review shows that ionizing radiation in biological membranes and in pure lipid membranes causes malondialdehyde formation, indicating lipid peroxidation processes. With respect to membrane fluidization by ionizing radiation, in pure lipid membranes rigidization effects are always reported, whereas contradictory results exist for biological membranes. Starting from the assumption that membrane proteins at least partly compensate for radiation effects leading to a rigidization of membrane lipid regions, pig liver microsomes, as a representative protein-rich intracellular membrane system, were irradiated with X-rays or UV-C with doses up to 120 Gy at a dose rate of 0.67 Gy min^–1 and up to 0.73 J cm^–2 at an exposure rate of 16.2 mJ cm^–2 min^–1, respectively. For both irradiation types a weak but significant positive correlation between malondialdehyde formation and membrane fluidity is revealed throughout the applied dose ranges. We conclude that the membraneous protein lipid interface increases its fluidity under radiation conditions. Also, thymocyte ghosts showed an increased fluidity after X-ray irradiation. Fluidity measurements were performed by the pyrene excimer method.     

A scanning electron microscope study of normal and vitrified leaves from Datura insignis plantlets cultured in vitro

The surface anatomy of normal and vitreous leaves of plantlets obtained from Datura insignis Barb Rodr nodal segment cultures was compared using scanning electron microscopy. Normal and vitrified leaves are similar in several ways. They are both amphistomatic, and have similar distributions of glandular and non-glandular trichomes. Stomata have similar length, diameter and distribution in normal and vitreous plants. Immature stomata, which have closed pores, and plugged stomata, which contain an amorphous material between their guard cells, occur in both normal and vitrified leaves. Normal and vitreous leaves differ in the frequency of normal and abnormal stomata. Normal stomata have kidney-shaped guard cells and resemble closely those found in field-grown plants, whereas abnormal stomata have deformed guard cells. Normal stomata represent approximately 80% of the total number of stomata in normal leaves, but only 7% of the total number of stomata in vitreous leaves. Abnormal stomata represent 90% of the total number in vitreous leaves. The deformation of guard cells could possibly be a mechanical impediment to stomatal function.     

Culture of Hypnea musciformis (Rhodophyta,Gigartinales) on artificial substrates attached to linear ropes

Hypnea musciformis is the only species so far exploited in Brazil as raw material for the production of k-carrageenan. Due to the erratic production in space and time, increasing harvest and transportation costs, experiments have been performed in order to assess the viability of H. musciformis mariculture.In nature the species occurs as an epiphyte, and so mariculture using artificial substrates that simulated the natural host of the species was tried. These substrates were attached, at regular intervals, to linear ropes. In the sea, these ropes were stretched between cement blocks.Seeding occurs naturally, by means of spores, or detached pieces of H. musciformis scattered in the water column that get entangled on the ropes. The best yields (0.54 wet kg m^–1 month^–1) were obtained with unthreaded rope substrates maintained in a vertical position by small rafts. Production is highest in the first 18 m off the rocky shore (0–2.1 m deep), at the highest substrate density utilized (10 m^–1), 2–3 months after installing the ropes in seawater. The main factor controlling seasonal production is water movement.     

Different signal transduction by epidermal growth factor may be responsible for the difference in modulation of amino acid transport between fetal and adult hepatocytes

[1-¹⁴C]-2-aminoisobutyric acid (AIB) uptake and signal transduction pattern after epidermal growth factor (EGF) stimulation were examined in freshly isolated hepatocytes from 20-day-old fetuses and 3-month-old rats. EGF induced a transient increase of AIB transport after 10 min only in adult animals; the observed unresponsiveness of fetal liver is not dependent on a lack of EGF receptors which are present though to a lesser extent on the plasma membrane in this period. As far as the production of the second messengers, inositol trisphosphate (IP₃) and calcium, is concerned, substantial differences were found: EGF increased IP₃ production in adult hepatocytes, whereas it had no effect in fetal ones. Moreover, the addition of EGF induced a calcium transient in hepatocytes from adult animals, while there was no increase in fetal cells. The lack of EGF effect on amino acid transport in fetal cells could be due to its inability to produce both IP₃ and calcium transients, suggesting that this transduction pathway is not activated during fetal life.     

Casearia Essential Oil: An Updated Review on the Chemistry and Pharmacological Activities

Casearia species are found in the America, Africa, Asia, and Australia and present pharmacological activities, besides their traditional uses. Here, we reviewed the chemical composition, content, pharmacological activities, and toxicity of the essential oils (EOs) from Casearia species. The EO physical parameters and leaf botanical characteristics were also described. The bioactivities of the EOs from the leaves and their components include cytotoxicity, anti-inflammatory, antiulcer, antimicrobial, antidiabetic, antioxidant, antifungal, and antiviral activities. The main components associated with these activities are the α-zingiberene, (E)-caryophyllene, germacrene D, bicyclogermacrene, spathulenol, α-humulene, β-acoradiene, and δ-cadinene. Data on the toxicity of these EOs are scarce in the literature. Casearia sylvestris Sw. is the most studied species, presenting more significant pharmacological potential. The chemical variability of EOs components was also investigated for this species. Caseria EOs have relevant pharmacological potential and must be further investigated and exploited.     

A proposito del llamado micetoma maduro-micosico del pulmon

Conclusiones Se efectúa el estudio de 5 observaciones del llamado Micetoma maduromicósico de pulmón en sus aspectos, histopatológico, micológico y clínico.Todas ellas pertenecen a mujeres y configuraron el cuadro de cavidad bronquial empastada, anotando el predominio de su localización en el lóbulo superior izquierdo.Se señala la uniformidad de los caracteres morfológicos que presenta la masa miceliana llamada grano en todos los casos estudiados, en los cuales no fué posible individualizar la existencia de órganos de fructificación que permitiéran una clasificación, cuando más no fuera, genérica del hongo observado.Se critica la aplicación del término Micetoma para éstos casos con igual criterio que el clásico, que supone una enfermedad micótica primitiva, razón por la cual se prefiere hablar de cavidad con contenido micótico o maduromicótico.En el único caso que se logró cultivar al hongo parásito, el estudio micológico del mismo permitió aislar una especie del GéneroAspergillua con caracteres morfológicos sumamente atípicos.

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Summary The author presents the study of five observations of the so-called Maduromycosis-mycetoma of the lungs in their clinical, histopathologic and mycologic aspects.The pathologic features in all these cases have been found in bronchial cavities of women, situated in the upper lobe of the lung. A compact mycelial mass, the grain, filled up these cavities.In one of the five cases a fungus was cultivated which was classified as belonging to the GenusAspergillus Michelii, with abnormal and atypical features.Short criticism is presented about the concept Maduromycosis mycetoma of the lung, applied by authors designating this process.

     

Signal transduction during liver regeneration: role of insulin and vasopressin.

The relationship between cell proliferation and inositol lipid turnover has been studied by comparing the steady state of inositol derivative metabolism in quiescent and regenerating rat hepatocytes isolated at 4 h (G1 phase of first cell cycle) and 24 h (onset of M phase) after partial hepatectomy. The effect of two hormones able to regulate hepatic regeneration, insulin and vasopressin, has been considered, and the results can be summarized as follows: (i) at 4 h after partial hepatectomy, the precursor incorporation into inositol polyphosphates and the particulate phospholipase C activity increase with respect to quiescent hepatocytes, whereas the content of 11, 4, 5P3 does not change, suggesting an increased turnover of this molecule in this step of cell cycle priming; (ii) 24 h after partial hepatectomy, the radioactivity linked to IP3 and IP4, as well as soluble and particulate phospholipase C activity, and IP3 content increase, suggesting the presence, at the onset of M phase, of second messenger accumulation; (iii) only 24 h after partial hepatectomy, the inositol derivative metabolism is affected by vasopressin; and (iv) insulin exerts a modulatory role on inositol polyphosphate production without involving membrane-bound PLC activity or phosphoinositide hydrolysis. These data suggest that inositol-derived signal molecules are associated with hepatic regeneration; moreover, the metabolic pathway of such compounds seems to be regulated so that only specific inositol phosphates are present in each step of the cell cycle.     

The K/Na and Ca/Na ratios and rapeseed yield,under soil salinity or sodicity

Rapeseed (Brassica napus) is a crop relatively tolerant to salt and sodium. Our objective was to study the interactions between Na, K and Ca and their relationship with its yield under the isolated effects of soil salinity or sodicity.Two experiments were carried out using pots filled with the Ah horizon of a Typic Natraquoll. There were three salinity levels (2.3 dS m^-1; 6.0 dS m^-1 and 10.0 dS m^-1) and three sodicity levels, expressed as sodium adsorption ratios (SAR: 12; 27 and 44). The soil was kept near field capacity.As soil salinity increased, the K/Na and Ca/Na ratios in the tissues decreased markedly but yields and aerial biomass production were not affected. As soil SAR value increased, the K/Na and Ca/Na ratios in plants and K-Na and Ca-Na selectivities decreased. Plants could not maintain their Ca concentration in soil with a high SAR. The grain yield and biomass production diminished significantly in the highest SAR treatment. Our results are consistent with those showing detrimental osmotic effects of salts in Brassica napus. Conversely, under sodicity, the K/Na and Ca/Na ratios in plant tissues decreased considerably, in accordance with grain and biomass production. These results show that the effects of sodicity are different from those of salinity.