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51.
Alvaro Díaz-Barrera Nataly Maturana Ivette Pacheco-Leyva Irene Martínez Claudia Altamirano 《Journal of industrial microbiology & biotechnology》2017,44(7):1041-1051
Alginate production and gene expression of genes involved in alginate biosynthesis were evaluated in continuous cultures under dissolved oxygen tension (DOT) controlled conditions. Chemostat at 8% DOT showed an increase in the specific oxygen uptake rate \((q_{{{\text{O}}_{ 2} }} )\) from 10.9 to 45.3 mmol g?1 h?1 by changes in the dilution rate (D) from 0.06 to 0.10 h?1, whereas under 1% DOT the \(q_{{{\text{O}}_{ 2} }}\) was not affected. Alginate molecular weight was not affected by DOT. However, chemostat at 1% DOT showed a downregulation up to 20-fold in genes encoding both the alginate polymerase (alg8, alg44), alginate acetylases (algV, algI) and alginate lyase AlgL. alyA1 and algE7 lyases gene expressions presented an opposite behavior by changing the DOT, suggesting that A. vinelandii can use specific depolymerases depending on the oxygen level. Overall, the DOT level have a differential effect on genes involved in alginate synthesis, thus a gene expression equilibrium determines the production of alginates of similar molecular weight under DOT controlled. 相似文献
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53.
Alvaro J.?Duque Joost F.?DuivenvoordenEmail author Jaime?Cavelier Mauricio?Sánchez Carolina?Polanía Andrea?León 《Plant Ecology》2005,178(1):1-13
In a case-study from Colombian Amazonia, species information from ferns and Melastomataceae was used to explain the compositional patterns of other vascular plant species in 40 widely distributed 0.1-ha plots. Canonical correspondence analysis was applied to regress vascular plant species composition in the forests against information from these two indicator groups (summarized as axes of principal coordinate analyses), together with that from soils, landscape, and the spatial sampling design. In total, 53,941 individuals of 2480 vascular plant species were recorded. Of these, 17,473 individuals and 132 species were from ferns and Melastomataceae. In 19 well-drained upland (tierra firme) plots 19,622 vascular plant individuals and 1716 species were found, with 3793 plants and 91 species from ferns and Melastomataceae. In both the set of all landscapes and the subset of tierra firme forests the principal PCoA axes of the two indicator groups were highly related to the main patterns of forest species composition. In principle, therefore, ferns and Melastomataceae can be used to detect and forecast changes in the forest composition of the study area. However, evidence was not obtained that ferns and Melastomataceae show more potential to predict the main patterns in species composition of forests than soil, landscape, and spatial variables. The partioning of the total variation in forest composition showed that the correlation of ferns and Melastomataceae with other forest plants was quite independent from that of soil, landscape, and space. Direct effects of ferns and Melastomataceae on other plants might be obtained from experimental studies of between-plant interactions, concentrating on the seedling or juvenile stages of trees and lianas, both above-ground as well as in the rooting environment. 相似文献
54.
Morphological assessment of the Octopus vulgaris species complex evaluated in light of molecular‐based phylogenetic inferences 下载免费PDF全文
Michael D. Amor Mark D. Norman Alvaro Roura Tatiana S. Leite Ian G. Gleadall Amanda Reid Catalina Perales‐Raya Chung‐Cheng Lu Colin J. Silvey Erica A. G. Vidal Frederick G. Hochberg Xiaodong Zheng Jan M. Strugnell 《Zoologica scripta》2017,46(3):275-288
Cryptic species are common in the ocean, particularly among marine invertebrates such as octopuses. Delineating cryptic species is particularly problematic in octopus taxonomy where the plasticity recorded among taxonomic characters often results in low resolution at the species level. This study investigated the morphological relationships among seven phylogenetic clades (identified using cytochrome c oxidase subunit I) of the broadly distributed Octopus vulgaris species complex and close relatives. Morphological analyses in this study were successful in delimiting O. sinensis, Brazilian O. vulgaris and O. vulgaris sensu stricto, which was congruent with the molecular findings of this study. Analyses based on male morphology were successful in distinguishing 14 of 15 total pairwise comparisons and proved to be a more reliable indicator of species‐level relationships in comparison with female morphology. The majority of characters with the greatest discriminatory power were male sexual traits. Significant morphological differences were also recorded among sampling localities of conspecifics, with phenotype showing correlation with local environmental data. The findings of this study support the hypothesis that multiple O. vulgaris‐like species are currently being incorrectly treated under a single species name, O. vulgaris. Octopuses being exported globally under the name O. vulgaris are of extremely high fisheries market value and profile. Our findings have potentially significant implications for the naming and conservation of commercially harvested members of this species complex throughout their ranges. 相似文献
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56.
Cianciarullo AM Bertho AL Soares MJ Hosoda TM Nogueira-Silva S Beçak W 《Cell biology international》2003,27(9):747-753
Properly metabolized globin synthesis and iron uptake are indispensable for erythroid cell differentiation and maturation. Mitochondrial participation is crucial in the process of haeme synthesis for cytochromes and haemoglobin. We studied the final biosynthesis site of haemoglobin using an ultrastructural approach, with erythroid cells obtained from rabbit embryos, in order to compare these results with those of animals treated with saponine or phenylhydrazine. Our results are similar to those obtained in assays with adult mammals, birds, amphibians, reptiles and fish, after induction of haemolytic anaemia. Therefore, the treatment did not interfere with the process studied, confirming our previous findings. Immunoelectron microscopy showed no labelling of mitochondria or other cellular organelles supposedly involved in the final biosynthesis of haemoglobin molecules, suggesting instead that it occurs free in the cytoplasm immediately after the liberation of haeme from the mitochondria, by electrostatic attraction between haeme and globin chains. 相似文献
57.
García JE Puentes A López R Vera R Suárez J Rodríguez L Curtidor H Ocampo M Tovar D Forero M Bermudez A Cortés J Urquiza M Patarroyo ME 《Peptides》2003,24(5):647-657
Synthetic peptides from the liver stage antigen-1 (LSA-1) antigen sequence were used in HepG2 cell and erythrocyte binding assays to identify regions that could be involved in parasite invasion. LSA-1 protein peptides 20630 ((21)INGKIIKNSEKDEIIKSNLRY(40)), 20637 ((157)KEKLQGQQSDSEQERRAY(173)), 20638 ((174)KEKLQEQQSDLEQERLAY(190)) and 20639 (191KEKLQEQQSDLEQERRAY(207)) had high binding activity in HepG2 assays. Were located in immunogenic regions; peptide cell binding was saturable. Peptide 20630 bound specifically to 48kDa HepG2 membrane surface protein. LSA-1 peptides 20630 ((21)INGKIIKNSEKDEIIKSNLRY(40)) and 20633 ((81)DKELTMSNVKNVSQTNFKSLY(100)) showed specific erythrocyte binding activity and inhibited merozoite invasion of erythrocytes in vitro. A monkey serum prepared against LSA-1 20630 peptide analog (CGINGKNIKNAEKPMIIKSNLRGC) inhibited merozoite invasion in vitro. The data suggest LSA-1 "High Activity Binding Peptides" could play a possible role in hepatic cell invasion as well as merozoite invasion of erythrocytes. 相似文献
58.
Alvaro Morales 《Cancer immunology, immunotherapy : CII》1980,9(1-2):69-72
Summary Although carcinoma in situ conveys the idea of an early neoplasm, such lesions in the bladder mucosa commonly exhibit a very aggressive behavior and carry a grave prognosis. Seven patients with in situ carcinoma of the bladder have been treated with intravesical and systemic administration of Bacillus Calmette-Guérin. Elimination of tumor was documented by endoscopy, histology and cytology in five patients. These five patients have remained tumor-free for periods ranging between 12 and 33 months (mean: 22.6). This preliminary study indicates that regional and systemic immunotherapy is an alternative worth additional investigation in patients with carcinoma in situ of the bladder. 相似文献
59.
Cristián Tapia Sergio Molina Alvaro Diaz Lilian Abugoch Mario Diaz-Dosque Fernando Valenzuela Mehrdad Yazdani-Pedram 《AAPS PharmSciTech》2010,11(3):1294-1305
The effect of chitosan as internal or external coating on the mesalamine (5-ASA) release from calcium alginate microparticles (CaAl) was studied, and a delayed release of 5-ASA system intended for colonic drug delivery was developed. The external chitosan coating was developed by immersion of wetted CaAl in chitosan solution and the internal coating by mixing 5-ASA with chitosan solution and drying before the preparation of CaAl. Both systems were coated with Acryl-EZE® using combined fluid bed coating and immersion procedure. The results showed that in phosphate medium (pH 7.5), chitosan as 5-ASA coating promotes a quick erosion process accelerating drug release, but chitosan as external coating (CaAlCS) does not increase the T 50 value compared with the microparticles without chitosan (CaAl). Chitosan as internal or external coating was not effective to avoid the quick 5-ASA release in acidic medium (pH 1.2). The presence of β-glucosidase enzymes increases significantly the 5-ASA release for CaAl, while no effect was observed with chitosan as internal or external coating. Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray data revealed that 5-ASA did not form a solid solution but was dispersed in the microparticles. The Acryl-EZE® coating of microparticles was effective because all the formulations showed a low release, less than 15%, of 5-ASA in acid medium at pH 1.2. Significant differences in the percentage of 5-ASA released between formulations were observed in phosphate buffer at pH 6.0. In phosphate buffer at pH 7.2, all the formulations released 100% of 5-ASA. 相似文献
60.
Alvaro A. Sandoval-Montiel Martha Zentella-de-Pi?a José L. Ventura-Gallegos Susana Frías-González Ambar López-Macay Alejandro Zentella-Dehesa 《PloS one》2013,8(6)