Amino Acids from <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> (L.) and <Emphasis Type="Italic">Rapana venosa</Emphasis> Molluscs Accelerate Skin Wounds Healing via Enhancement of Dermal and Epidermal Neoformation

Wound healing consists of re-epithelialization, contraction and formation of granulation and scar tissue. Amino acids from proteins are involved in these events, but their exact roles are not well understood. The present study was undertaken to investigate the anti-inflammatory effects of some amino acids from two molluscs, Mytilus galloprovincialis (L.) (Mediterranean mussel) and Rapana venosa (hard shell-clam) employed in induced skin burn injuries in Wistar rats. The treatment was evaluated in terms of essential amino acids composition which rendered the extracts very efficient in healing skin burns. The healing process was examined by periodic acid Schiff’s, Verhoeff’s Van Gieson and immunohistochemistry stains for collagen IV, CD 34 and CD 117 antibodies. According to the obtained results, as expressed by histological studies, the most abundant blood vessels, collagen fibres, basal and stem cells were found only for treated animals with amino acids from Rapana venosa extracts. The rich composition of amino acids from the two molluscs merits consideration as therapeutic agents in the treatment of skin burns.     

The role of the DNA hypermethylating agent Budesonide in the decatenating activity of DNA topoisomerase II

Catenations between sister chromatids result from DNA replication and must be resolved to ensure proper chromatid segregation in mitosis. Functionally active Topoisomerase II (Topo II), through its mechanism of concerted breaking and rejoining of double stranded DNA, is required to carry out this fundamental process. In previous studies we have shown that modifications in DNA sequence by halogenated pyrimidines and by the demethylating agent 5-azacytidine leads to malfunction of Topo II that results in an increased yield of endorreduplicated cells as a result of segregation failure. In the present work we have evaluated the possible influence of the methylating agent Budesonide to modify the frequency of endoreduplicated cells in AA8 Chinese hamster cell population. Our results seem to indicate that when Budesonide was administered for two consecutive cell cycles did induce an increase in the yield of endoreduplicated cells, as previously observed for the hypomethylating agent 5-azaC. We have also examined the possible relationship between extensive hypermethylation induced by Budesonide in DNA and stabilization of cleavable complexes by m-AMSA. Taken as a whole, our results show that the degree of methylation in DNA correlates with the effectiveness of m-AMSA to stabilize the Topo II-DNA complexes and to induce DNA cleavage. These findings evidence for the first time the functional importance of DNA hyper- and hypomethylation changes as epigenetic factors able to modulate Topo II activity for proper chromosome segregation.     

A rational use of glucocorticoids in patients with early arthritis has a minimal impact on bone mass

Introduction  

Glucocorticoid (GC)-induced osteoporosis is a frequent complication in patients with rheumatoid arthritis. However, little information exists about the consequences of GC use in patients with early arthritis. Here we describe the variables underlying the use of GC in early arthritis, as well as its effect on bone-mineral density.     

Changes in photosynthetic electron transfer and state transitions in an herbicide-resistant D1 mutant from soybean cell cultures

Anomalies in photosynthetic activity of the soybean cell line STR7, carrying a single mutation (S268P) in the chloroplastic gene psbA that codes for the D1 protein of the photosystem II, have been examined using different spectroscopic techniques. Thermoluminescence emission experiments have shown important differences between STR7 mutant and wild type cells. The afterglow band induced by both white light flashes and far-red continuous illumination was downshifted by about 4 °C and the Q band was upshifted by 5 °C. High temperature thermoluminescence measurements suggested a higher level of lipid peroxidation in mutant thylakoid membranes. In addition, the reduction rate of P700⁺ was significantly accelerated in STR7 suggesting that the mutation led to an activation of the photosystem I cyclic electron flow. Modulated fluorescence measurements performed at room temperature as well as fluorescence emission spectra at 77 K revealed that the STR7 mutant is defective in state transitions. Here, we discuss the hypothesis that activation of the cyclic electron flow in STR7 cells may be a mechanism to compensate the reduced activity of photosystem II caused by the mutation. We also propose that the impaired state transitions in the STR7 cells may be due to alterations in thylakoid membrane properties induced by a low content of unsaturated lipids.     

Struvite precipitation by soil and fresh water bacteria

Struvite precipitation by 161 bacterial strains isolated from soil and fresh water was analyzed. The results showed that the ability to form struvite is not widespread among these bacteria. Struvite precipitation was influenced by environmental factors and could be enhanced by changing the experimental conditions. There was no clear relationship between the taxonomic status of a given strain and its ability to precipitate struvite. However, bacteria of the genusPseudomonas showed a greater tendency to precipitate struvite than organisms of the remaining genera studied, and five new genera were identified as struvite producers.     

Natural hybridization among subspecies of <Emphasis Type="Italic">Turnera sidoides</Emphasis> L. (Passifloraceae) revealed by morphological and genetic evidence

Turnera sidoides is a complex of outcrossing, perennial, rhizomatous herbs that is widely distributed in southern South America. Five subspecies are recognized taxonomically based on morphological features and geographical distribution. In certain regions, the areas of distribution of the subspecies overlap partially. In such contact zones, the extent of reproductive barriers among subspecies is still largely unknown, but morphologically intermediate individuals have been found in the field, indicating that hybridization may actually occur between subspecies. Crossability among subspecies of T. sidoides has been shown by experimental studies with cultivated plants, but the mechanisms involved in natural populations are still unknown. To investigate the mechanisms that underlie gene flow within the T. sidoides complex, in this paper we analyze the morphological and genetic variation, as well as the crossability among taxa in a contact zone between subspecies pinnatifida and sidoides, in southeastern Uruguay. Our results constitute the first evidences of ongoing natural hybridization between subspecies of T. sidoides and suggest that, although hybridization may not have been of significance in the early phase of the species differentiation, reticulate evolution is ongoing enhancing the current morphological and genetic variability of the complex.     

High yield of endoreduplication induced by ICRF-193: a topoisomerase II catalytic inhibitor

Previous studies have demonstrated that phenolic compounds, including genistein (4',5,7-trihydroxyisoflavone) and resveratrol (3,4',5-trihydroxystilbene), are able to protect against carcinogenesis in animal models. This study was undertaken to examine the ability of genistein and resveratrol to inhibit reactive oxygen species (ROS)-mediated strand breaks in phi X-174 plasmid DNA. H(2)O(2)/Cu(II) and hydroquinone/Cu(II) were used to cause oxidative DNA strand breaks in the plasmid DNA. We demonstrated that the presence of genistein at micromolar concentrations resulted in a marked inhibition of DNA strand breaks induced by either H(2)O(2)/Cu(II) or hydroquinone/Cu(II). Genistein neither affected the Cu(II)/Cu(I) redox cycle nor reacted with H(2)O(2) suggest that genistein may directly scavenge the ROS that participate in the induction of DNA strand breaks. In contrast to the inhibitory effects of genistein, the presence of resveratrol at similar concentrations led to increased DNA strand breaks induced by H(2)O(2)/Cu(II). Further studies showed that in the presence of Cu(II), resveratrol, but not genistein was able to cause DNA strand breaks. Moreover, both Cu(II)/Cu(I) redox cycle and H(2)O(2) were shown to be critically involved in resveratrol/copper-mediated DNA strand breaks. The above results indicate that despite their similar in vivo anticarcinogenic effects, genistein and resveratrol appear to exert different effects on oxidative DNA damage in vitro.     

Molecular evidence and clinical importance of β‐arrestins expression in patients with acromegaly

β‐arrestins seem to have a role in endocytosis and desensitization of somatostatin receptor subtype 2 (sst2) and could be associated with the responsiveness to somatostatin receptor ligands (SRL) in patients with acromegaly. To investigate the in vivo correlation between β‐arrestins 1 and 2 with sst2, sst5 and dopamine receptor subtype 2 (D2) expressions, and the association of β‐arrestins with response to first‐generation SRL and invasiveness in somatotropinomas. β‐arrestins 1 and 2, sst2, sst5 and D2 mRNA expressions were evaluated by quantitative real‐time RT‐PCR on tumoral tissue of 96 patients. Moreover, sst2 and sst5 protein expressions were also evaluated in 40 somatotropinomas by immunohistochemistry. Response to SRL, defined as GH <1 μg/l and normal IGF‐I levels, was assessed in 40 patients. The Knosp‐Steiner criteria were used to define invasiveness. Median β‐arrestin 1, β‐arrestin 2, sst2, sst5 and D2 mRNA copy numbers were 478; 9375; 731; 156 ; and 3989, respectively. There was a positive correlation between β‐arrestins 1 and 2 (R = 0.444, P < 0.001). However, no correlation between β‐arrestins and sst2, sst5 (mRNA and protein levels) or D2 was found. No association was found between β‐arrestins expression and SRL responsiveness or tumour invasiveness. Although previous data suggest a putative correlation between β‐arrestins and sst2, our data clearly indicated that no association existed between β‐arrestins and sst2, sst5 or D2 expression, nor with response to SRL or tumour invasiveness. Therefore, further studies are required to clarify whether β‐arrestins have a role in the response to treatment with SRL in acromegaly.