The aim of this study was to analyze C and N dynamics, as well as, soil bacterial community struc... more The aim of this study was to analyze C and N dynamics, as well as, soil bacterial community structure within soil micro- and macro-aggregates in a tropical deciduous forest in México. We measured, for three landscape positions and three seasons of the year: total, microbial and available forms of C and N; potential C and N mineralization; and soil bacterial communities by using t-RFLPs. The highest total C concentrations were found in the north-slopes and in the dry season (DS) samples. In general, micro-aggregates had higher concentrations than macro-aggregates of available C and N forms, and microbial C. Similarly, micro-aggregates had the highest potential C mineralization and net N mineralization. We detected 149 different OTUs (operational taxonomic units) from which 50% was shared by the two aggregate size fractions, 25% was exclusive to micro-aggregates and the 25% left was found only in macro-aggregates. Top-hills were richer in OTUs than north and south-slopes. The Unweighted Pair Group Method with Arithmetic mean (UPGMA) analysis indicated clear differences in community composition between the two aggregate size-fractions in relation to the presence of OTUs. These results suggest that the main difference between micro- and macro-aggregates is due to the community structure within each soil fraction and this difference could affect soil nutrients dynamics.
Page 301. Merging Capabilities with the Object Model of an Object-Oriented Abstract Machine Maria... more Page 301. Merging Capabilities with the Object Model of an Object-Oriented Abstract Machine Maria Angeles Diaz Fondon1, Darfo Alvarez Gutierrez1, Armando Garcia-Mendoza Sanchez1, Fernando Alvarez Garcia1, Lourdes ...
In contrast to the thoroughly characterized mechanisms of positive regulation within cytokine sig... more In contrast to the thoroughly characterized mechanisms of positive regulation within cytokine signaling pathways, our knowledge of negative feedback loops is comparatively sparse. We and others have previously reported that IRAK-M down-regulates inflammatory responses to multiple stimuli. In particular, we could show that the nitric oxide (NO) donor, GSNO, induces IRAK-M overexpression in human monocytes. Here we study the expression of another important negative regulator of cytokine signaling, SOCS-1, in human monocytes exposed to GSNO. The NO donor induced significant levels of SOCS-1 mRNA and protein, 6 h and 16 h after stimulation, respectively. Monocytes stimulated with GSNO for longer periods (24 h and 48 h) failed to express IL-6 and IP-10 upon LPS challenge. In addition, and in line with previous reports of NO-mediated induction of TNF-alpha, we have found that exposure to this cytokine induces SOCS-1 mRNA in human monocytes. A blocking antibody against TNF-alpha impaired SOCS-1 expression upon GSNO treatment and re-instated IL-6 and IP-10 mRNA levels after LPS challenge in cultures pretreated with the NO donor. We conclude that NO stimulates SOCS-1 overexpression in a pathway at least partially regulated by TNF-alpha.
The HTLV-1 envelope gene of 12 TSP/HAM patients from two endemic areas of southwest Colombia (Tum... more The HTLV-1 envelope gene of 12 TSP/HAM patients from two endemic areas of southwest Colombia (Tumaco and Buenaventura) was amplified by nested PCR, sequenced, and compared with previously reported HTLV-1 envelope sequences from isolates worldwide. In general, the sequence divergences among all Colombian samples ranged from 0.1 to 1.6%. Some amino acid substitutions, referring to the ATK-1 prototype strain in the surface domain gp46 and in p21, were highly prevalent in southwest Colombia, suggesting a geographical clustering of mutations in the envelope gene. The phylogenetic analysis showed that the Colombian isolates belong to the HTLV-1a lineage with minor subgroups. The genetic distance between Colombian and Japanese isolates ranged from 0.1 to 1.8%; in comparison, the genetic distance between Colombian and Caribbean isolates ranged from 0.4 to 2.2%. Our results strongly suggest that the actual quasispecies populations in southwest Colombia have been generated by separate, differently timed introductions of virus.
... Best Practices in Mexico Rodrigo Sandoval Almazan Jeanett Mendoza Col??n Universidad Autonoma... more ... Best Practices in Mexico Rodrigo Sandoval Almazan Jeanett Mendoza Col??n Universidad Autonoma del Estado de M??xico, Toluca 50000 {rsandovala, jmendoza}@uaemex.mx J. Ramon Gil-Garcia ... 5. REFERENCES [1] Toffler, A.(1980), La tercera ola, 1a. Ed espa??ol. ...
The aim of this study was to analyze C and N dynamics, as well as, soil bacterial community struc... more The aim of this study was to analyze C and N dynamics, as well as, soil bacterial community structure within soil micro- and macro-aggregates in a tropical deciduous forest in México. We measured, for three landscape positions and three seasons of the year: total, microbial and available forms of C and N; potential C and N mineralization; and soil bacterial communities by using t-RFLPs. The highest total C concentrations were found in the north-slopes and in the dry season (DS) samples. In general, micro-aggregates had higher concentrations than macro-aggregates of available C and N forms, and microbial C. Similarly, micro-aggregates had the highest potential C mineralization and net N mineralization. We detected 149 different OTUs (operational taxonomic units) from which 50% was shared by the two aggregate size fractions, 25% was exclusive to micro-aggregates and the 25% left was found only in macro-aggregates. Top-hills were richer in OTUs than north and south-slopes. The Unweighted Pair Group Method with Arithmetic mean (UPGMA) analysis indicated clear differences in community composition between the two aggregate size-fractions in relation to the presence of OTUs. These results suggest that the main difference between micro- and macro-aggregates is due to the community structure within each soil fraction and this difference could affect soil nutrients dynamics.
Page 301. Merging Capabilities with the Object Model of an Object-Oriented Abstract Machine Maria... more Page 301. Merging Capabilities with the Object Model of an Object-Oriented Abstract Machine Maria Angeles Diaz Fondon1, Darfo Alvarez Gutierrez1, Armando Garcia-Mendoza Sanchez1, Fernando Alvarez Garcia1, Lourdes ...
In contrast to the thoroughly characterized mechanisms of positive regulation within cytokine sig... more In contrast to the thoroughly characterized mechanisms of positive regulation within cytokine signaling pathways, our knowledge of negative feedback loops is comparatively sparse. We and others have previously reported that IRAK-M down-regulates inflammatory responses to multiple stimuli. In particular, we could show that the nitric oxide (NO) donor, GSNO, induces IRAK-M overexpression in human monocytes. Here we study the expression of another important negative regulator of cytokine signaling, SOCS-1, in human monocytes exposed to GSNO. The NO donor induced significant levels of SOCS-1 mRNA and protein, 6 h and 16 h after stimulation, respectively. Monocytes stimulated with GSNO for longer periods (24 h and 48 h) failed to express IL-6 and IP-10 upon LPS challenge. In addition, and in line with previous reports of NO-mediated induction of TNF-alpha, we have found that exposure to this cytokine induces SOCS-1 mRNA in human monocytes. A blocking antibody against TNF-alpha impaired SOCS-1 expression upon GSNO treatment and re-instated IL-6 and IP-10 mRNA levels after LPS challenge in cultures pretreated with the NO donor. We conclude that NO stimulates SOCS-1 overexpression in a pathway at least partially regulated by TNF-alpha.
The HTLV-1 envelope gene of 12 TSP/HAM patients from two endemic areas of southwest Colombia (Tum... more The HTLV-1 envelope gene of 12 TSP/HAM patients from two endemic areas of southwest Colombia (Tumaco and Buenaventura) was amplified by nested PCR, sequenced, and compared with previously reported HTLV-1 envelope sequences from isolates worldwide. In general, the sequence divergences among all Colombian samples ranged from 0.1 to 1.6%. Some amino acid substitutions, referring to the ATK-1 prototype strain in the surface domain gp46 and in p21, were highly prevalent in southwest Colombia, suggesting a geographical clustering of mutations in the envelope gene. The phylogenetic analysis showed that the Colombian isolates belong to the HTLV-1a lineage with minor subgroups. The genetic distance between Colombian and Japanese isolates ranged from 0.1 to 1.8%; in comparison, the genetic distance between Colombian and Caribbean isolates ranged from 0.4 to 2.2%. Our results strongly suggest that the actual quasispecies populations in southwest Colombia have been generated by separate, differently timed introductions of virus.
... Best Practices in Mexico Rodrigo Sandoval Almazan Jeanett Mendoza Col??n Universidad Autonoma... more ... Best Practices in Mexico Rodrigo Sandoval Almazan Jeanett Mendoza Col??n Universidad Autonoma del Estado de M??xico, Toluca 50000 {rsandovala, jmendoza}@uaemex.mx J. Ramon Gil-Garcia ... 5. REFERENCES [1] Toffler, A.(1980), La tercera ola, 1a. Ed espa??ol. ...
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