Scielo RSS <![CDATA[Biological Research]]> https://scielo.conicyt.cl/rss.php?pid=0716-976020060005&lang=en vol. 39 num. 4 lang. en <![CDATA[SciELO Logo]]> https://scielo.conicyt.cl/img/en/fbpelogp.gif https://scielo.conicyt.cl <![CDATA[<b>UNA NUEVA ETAPA</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500001&lng=en&nrm=iso&tlng=en <![CDATA[<b>Role of nitric oxide during neurogenesis in the olfactory epithelium</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500002&lng=en&nrm=iso&tlng=en In mammals, neurogenesis continues during adulthood in restricted places of the nervous system, namely the subventricular zone, the dentate gyms and the olfactory epithelium. A dual role of the second messenger nitric oxide has been reported in such places, either promoting or inhibiting proliferation of neuronal precursors depending on the cellular signal implicated. In this review the regulation of adult olfactory epithelium neurogenesis by nitric oxide is discussed <![CDATA[<b>Spatial cognition and memory</b>: <b>a reversible lesion with lidocaine into the anteromedial/posterior parietal cortex (AM/PPC) affects differently working and long-term memory on two foraging tasks</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500003&lng=en&nrm=iso&tlng=en Place memory is relevant for exploration and forage behaviour. When food supply is dispersed, a win-shift has advantage over a win-stay strategy. In the Olton Octagonal Maze, the rat follows a win-shift strategy using working memory. However, in the Olton 4x4 version, the rat follows a win-stay strategy, using both working and long-term memories. It has been suggested that the neocortex is required for the resolution of tasks demanding long-term, but not for that demanding working memory alone. The role of anteromedial/posterior parietal cortex (AM/PPC) was investigated here, using a reversible lesion induced by intracerebral lidocaine infusion. Long-Evans rats were implanted with guide cannulae into the AM/PPC and trained in an Olton 4x4 maze, counting working and long-term memory errors after a delay. Then, the animals were infused with lidocaine or saline during the delay phase and tested for three days. Another series of animals, treated as before, was tested in an Olton Octagonal Maze and subjected to the same injection schedule. In the Olton 4x4 Maze, lidocaine produced a significant increase in working and long-term memory errors, compared to saline and post-lidocaine conditions. In contrast, in the Olton Octagonal Maze, lidocaine did not induce any effect on working memory errors. Thus, AM/PPC is required when both working with previous information and long-term memories are needed, but not when only working memory is required, as it happens under ethological conditions. Whenever food supply is dispersed, a win-shift strategy is preferable <![CDATA[<b>The role of thyroid hormone calorigenesis in the redox regulation of gene expression</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500004&lng=en&nrm=iso&tlng=en Thyroid hormone (TH; 3,3',5-triiodothyronine, T3) is required for the normal function of most tissues, with major effects on 0(2) consumption and metabolic rate. These are due to transcriptional activation of respiratory genes through the interaction of T3-liganded TH receptors with TH response elements or the activation of intermediate factors, with the consequent higher production of reactive 0(2) species (ROS) and antioxidant depletion. T3-induced oxidative stress in the liver triggers the redox upregulation of the expression of cytokines (tumor necrosis factor-á [TNF-á], interleukin-10), enzymes (inducible nitric oxide synthase, manganese superoxide dismutase), and anti-apoptotic proteins (Bcl-2), via a cascade initiated by TNF-á produced by Kupffer cells, involving inhibitor of κB phosphorylation and nuclear factor-κB activation. Thus, TH calorigenesis triggers an expression pattern that may represent an adaptive mechanism to re-establish redox homeostasis and promote cell survival under conditions of ROS toxicity secondary to TH-induced oxidative stress. Mechanisms of expression of respiratory and redox-sensitive genes may be functionally integrated, which could be of importance to understand the complexities of TH action and the outcome of thyroid gland dysfunction <![CDATA[<b>Lipid peroxidation and antioxidant status in blood of patients with uterine myoma, endometrial polypus, hyperplastic and malignant endometrium</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500005&lng=en&nrm=iso&tlng=en Oxidative stress is considered to be involved in pathogenesis of many disorders of the female genital tract. In this study, we explored the lipid peroxidation levels and antioxidant enzyme activities in women diagnosed with different forms of uterine diseases in order to evaluate the extent of oxidative stress in blood of such patients. Blood samples of healthy subjects and gynecological patients were collected and subjected to assays for superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and lipid hydroperoxides. The results show that alterations of measured parameters vary with the enzyme type and diagnosis. However, both reduction in antioxidants and elevation of lipid peroxidation were observed in general. Lipid hydroperoxides level was negatively correlated to superoxide dismutase and glutathione peroxidase activities, as well as positively correlated to catalase activity. In addition, the lipid hydroperoxides/ glutathione peroxidase ratio was found to be increased, according to the type of uterine disease. The obtained results show that perturbation of antioxidant status is more pronounced in blood of patients with premalignant (hyperplastic) and malignant (adenocarcinoma) lesions, compared to those with benign uterine changes such as polypus and myoma <![CDATA[<b>Effect of heparin on <i>in vitro </i>capacitation of boar sperm</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500006&lng=en&nrm=iso&tlng=en Chlortetracycline (CTC) fluorescent pattern, the ability to undergo acrosome reaction (AR) upon exposure to 10 µM calcium ionophore A23187 and vitality estimation were used to investigate the effect of the sulfated glycosaminoglycan heparin on the in vitro capacitation of porcine spermatozoa. Sperm incubation in capacitating medium (CM) supplemented with 10 mM heparin for up to 120 min, showed an increase in the number of capacitated sperm (B pattern) and acrosome reacted sperm (AR pattern), without affecting their viability. In this condition, spermatozoa were incubated in CM depleted of albumin, calcium, bicarbonate or combinations, in the presence of heparin. In either calcium or bicarbonate-free media, capacitation was only basal and did not show variations in the presence of heparin. In absence of albumin the presence of calcium and bicarbonate stimulated capacitation, which was further increased by the addition of heparin. These results suggest that heparin enhances in vitro capacitation of porcine sperm only under capacitating conditions. Additionally, when sperm were incubated with 100 µg/ml biotinylated heparin in the presence or absence of unlabeled heparin, we observed that heparin binding sites were located mostly on the acrosomal region of boar sperm in an specific and saturable manner. The in vitro effect of heparin described in this work indicates that sulfated glycosaminoglycans, which are normally present in the female reproductive tract, might play an important role in the fertilization process in porcines. <![CDATA[<b>Cloning and functional characterization of the gene encoding the transcription factor Acel in the basidiomycete <i>Phanerochaete chrysosporium</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500007&lng=en&nrm=iso&tlng=en In this report we describe the isolation and characterization of a gene encoding the transcription factor Acel (Activation protein of cup 1 Expression) in the white rot fungus Phanerochaete chrysosporium. Pc-acel encodes a predicted protein of 633 amino acids containing the copper-fist DNA binding domain typically found in fungal transcription factors such as Acel, Macl and Haal from Saccharomyces cerevisiae. The Pc-acel gene is localized in Scaffold 5, between coordinates 220841 and 222983. A S. cerevisiae acel null mutant strain unable to grow in high-copper medium was fully complemented by transformation with the cDNA of Pc-acel. Moreover, Northern blot hybridization studies indicated that Pc-acel cDNA restores copper inducibility of the yeast cup 1 gene, which encodes the metal-binding protein metallothionein implicated in copper resistance. To our knowledge, this is first report describing an Acel transcription factor in basidiomycetes <![CDATA[<b>Bioinformatic prediction of polymerase elements in the rotavirus VP1 protein</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500008&lng=en&nrm=iso&tlng=en Rotaviruses are the major cause of acute gastroenteritis in infants world-wide. The genome consists of eleven double stranded RNA segments. The major segment encodes the structural protein VP1, the viral RNA-dependent RNA polymerase (RdRp), which is a minor component of the viral inner core. This study is a detailed bioinformatic assessment of the VP1 sequence. Using various methods we have identified canonical motifs within the VP1 sequence which correspond to motifs previously identified within RdRps of other positive strand, double-strand RNA viruses. The study also predicts an overall structural conservation in the middle region that may correspond to the palm subdomain and part of the fingers and thumb subdomains, which comprise the polymerase core of the protein. Based on this analysis, we suggest that the rotavirus replicase has the minimal elements to function as an RNA-dependent RNA polymerase. VP1, besides having common RdRp features, also contains large unique regions that might be responsible for characteristic features observed in the Reoviridae family <![CDATA[<b><i>Geobacillus stearothermophilus </i>LV <i>cadA </i>gene mediates resistance to cadmium, lead and zinc in <i>zntA </i>mutants of <i>Salmonella entérica </i>serovar Typhimurium</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500009&lng=en&nrm=iso&tlng=en Salmonella entérica serovar Typhimurium cells expressing the cadA gene of Geobacillus stearothermophilus LV exhibit a hypersensitive phenotype to cadmium chloride. Deletion of the ORF STM3576 from the Salmonella genome resulted in cadmium, lead and zinc sensitivity, confirming that this ORF is a homologue of the zntA gene. The observed sensitivity was reverted upon expression of the G. stearothermophilus LV cadA gene. These results indicate that the cadA gene product is involved in Cd, Pb and Zn resistance as a classical P-type ATPase and strongly suggest that the observed hypersensitive phenotype to these metals can be related to the function of the host ·zntA gene product <![CDATA[<b>Isolation and characterization of cultivable fermentative bacteria from the intestine of two edible snails, <i>Helixpomatia </i>and <i>Cornu aspersum </i>(Gastropoda: Pulmonata)</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500010&lng=en&nrm=iso&tlng=en The intestinal microbiota of the edible snails Cornu aspersum fSyn: H. aspersa), and Helix pomatia were investigated by culture-based methods, 16S rRNA sequence analyses and phenotypic characterisations. The study was carried out on aestivating snails and two populations of H. pomatia were considered. The cultivable bacteria dominated in the distal part of the intestine, with up to 5.10(9) CFU g -1, but the Swedish H. pomatia appeared significantly less colonised, suggesting a higher sensitivity of its microbiota to climatic change. All the strains, but one, shared ≥ 97% sequence identity with reference strains. They were arranged into two taxa: the Gamma Proteobacteria with Buttiauxella, Citrobacter, Enterobacter, Kluyvera, Obesumbacterium, Raoultella and the Firmicutes with Enterococcus, Lactococcus, and Clostridium. According to the literature, these genera are mostly assigned to enteric environments or to phyllosphere, data in favour of culturing snails in contact with soil and plants. None of the strains were able to digest filter paper, Avicel cellulose or carboxymethyl cellulose (CMC). Acetogens and methanogenic archaea were not cultivated, so the fate of hydrogen remains questionable. This microbiota could play important roles in the digestive process (fermentation) and the energy supply of the snail (L-lactate, acetate). The choice of cereals and plants by snail farmers should take into account the fermentative abilities of the intestinal microbiota <![CDATA[<b>FE DE ERRATA</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000500011&lng=en&nrm=iso&tlng=en The intestinal microbiota of the edible snails Cornu aspersum fSyn: H. aspersa), and Helix pomatia were investigated by culture-based methods, 16S rRNA sequence analyses and phenotypic characterisations. The study was carried out on aestivating snails and two populations of H. pomatia were considered. The cultivable bacteria dominated in the distal part of the intestine, with up to 5.10(9) CFU g -1, but the Swedish H. pomatia appeared significantly less colonised, suggesting a higher sensitivity of its microbiota to climatic change. All the strains, but one, shared ≥ 97% sequence identity with reference strains. They were arranged into two taxa: the Gamma Proteobacteria with Buttiauxella, Citrobacter, Enterobacter, Kluyvera, Obesumbacterium, Raoultella and the Firmicutes with Enterococcus, Lactococcus, and Clostridium. According to the literature, these genera are mostly assigned to enteric environments or to phyllosphere, data in favour of culturing snails in contact with soil and plants. None of the strains were able to digest filter paper, Avicel cellulose or carboxymethyl cellulose (CMC). Acetogens and methanogenic archaea were not cultivated, so the fate of hydrogen remains questionable. This microbiota could play important roles in the digestive process (fermentation) and the energy supply of the snail (L-lactate, acetate). The choice of cereals and plants by snail farmers should take into account the fermentative abilities of the intestinal microbiota