Homosexualidad y Discriminación: Tres estudios de caso en Toluca 2012

El presente trabajo de investigación centra su interés en la necesidad de evidenciar la discriminación que aún hoy en día se mantiene hacia las personas gay u homosexuales, por el simple hecho de mostrar una preferencia sexual diferente a la de la mayoría, con el objetivo de poder conocer el entorno social en el que se desenvuelven, la adquisición del concepto preformado de lo que es un homosexual, y las situaciones que viven día a día estos individuos bajo patrones de discriminación, ocasionados por vivir en una sociedad machista y poco conocedora de temas de diversidad sexual, situación que mantiene limitados los derechos en general de las parejas gay, pues ante el Estado estas parejas no existen por no seguir el patrón de familias tradicionales, por no ser una “familia normal”, evidenciando la diferenciación que puede hacerse a ciertos ciudadanos por el simple hecho de mostrar una preferencia sexual distinta a la establecida por la sociedad como sexualidad “normal”, excluyéndolos de vivir un desarrollo pleno por el simple hecho de no ser heterosexuales. A pesar de cierto avance en el ámbito jurídico, la ley ha cambiado, pero la sociedad no cambia en automático, haciendo evidente una ausencia de actuar por parte del Estado, para la integración armónica de la sociedad y aquellos miembros gay

Sinorhizobium meliloti Mutants Deficient in Phosphatidylserine Decarboxylase Accumulate Phosphatidylserine and Are Strongly Affected during Symbiosis with Alfalfa▿ †

Sinorhizobium meliloti contains phosphatidylglycerol, cardiolipin, phosphatidylcholine, and phosphatidylethanolamine (PE) as major membrane lipids. PE is formed in two steps. In the first step, phosphatidylserine synthase (Pss) condenses serine with CDP-diglyceride to form phosphatidylserine (PS), and in the second step, PS is decarboxylated by phosphatidylserine decarboxylase (Psd) to form PE. In this study we identified the sinorhizobial psd gene coding for Psd. A sinorhizobial mutant deficient in psd is unable to form PE but accumulates the anionic phospholipid PS. Properties of PE-deficient mutants lacking either Pss or Psd were compared with those of the S. meliloti wild type. Whereas both PE-deficient mutants grew in a wild-type-like manner on many complex media, they were unable to grow on minimal medium containing high phosphate concentrations. Surprisingly, the psd-deficient mutant could grow on minimal medium containing low concentrations of inorganic phosphate, while the pss-deficient mutant could not. Addition of choline to the minimal medium rescued growth of the pss-deficient mutant, CS111, to some extent but inhibited growth of the psd-deficient mutant, MAV01. When the two distinct PE-deficient mutants were analyzed for their ability to form a nitrogen-fixing root nodule symbiosis with their alfalfa host plant, they behaved strikingly differently. The Pss-deficient mutant, CS111, initiated nodule formation at about the same time point as the wild type but did form about 30% fewer nodules than the wild type. In contrast, the PS-accumulating mutant, MAV01, initiated nodule formation much later than the wild type and formed 90% fewer nodules than the wild type. The few nodules formed by MAV01 seemed to be almost devoid of bacteria and were unable to fix nitrogen. Leaves of alfalfa plants inoculated with the mutant MAV01 were yellowish, indicating that the plants were starved for nitrogen. Therefore, changes in lipid composition, including the accumulation of bacterial PS, prevent the establishment of a nitrogen-fixing root nodule symbiosis

The GacS/A-RsmA Signal Transduction Pathway Controls the Synthesis of Alkylresorcinol Lipids that Replace Membrane Phospholipids during Encystment of <i>Azotobacter vinelandii</i> SW136

<div><p><i>Azotobacter vinelandii</i> is a soil bacterium that undergoes a differentiation process that forms cysts resistant to desiccation. During encystment, a family of alkylresorcinols lipids (ARs) are synthesized and become part of the membrane and are also components of the outer layer covering the cyst, where they play a structural role. The synthesis of ARs in <i>A</i>. <i>vinelandii</i> has been shown to occur by the activity of enzymes encoded in the <i>arsABCD</i> operon. The expression of this operon is activated by ArpR, a LysR-type transcriptional regulator whose transcription occurs during encystment and is dependent on the alternative sigma factor RpoS. In this study, we show that the two component response regulator GacA, the small RNA RsmZ1 and the translational repressor protein RsmA, implicated in the control of the synthesis of other cysts components (i.e., alginate and poly-ß-hydroxybutyrate), are also controlling alkylresorcinol synthesis. This control affects the expression of <i>arsABCD</i> and is exerted through the regulation of <i>arpR</i> expression. We show that RsmA negatively regulates <i>arpR</i> expression by binding its mRNA, repressing its translation. GacA in turn, positively regulates <i>arpR</i> expression through the activation of transcription of RsmZ1, that binds RsmA, counteracting its repressor activity. This regulatory cascade is independent of RpoS. We also show evidence suggesting that GacA exerts an additional regulation on <i>arsABCD</i> expression through an ArpR independent route.</p></div

OlsG (Sinac-1600) Is an ornithine lipid N-Methyltransferase from the planctomycete Singulisphaera acidiphila

Ornithine lipids (OLs) are phosphorus-free membrane lipids widespread in bacteria but absent from archaea and eukaryotes. In addition to the unmodified OLs, a variety of OL derivatives hydroxylated in different structural positions has been reported. Recently, methylated derivatives of OLs were described in several planctomycetes isolated from a peat bog in Northern Russia, although the gene/enzyme responsible for the N-methylation of OL remained obscure. Here we identify and characterize the OL N-methyltransferase OlsG (Sinac-1600) from the planctomycete Singulisphaera acidiphila. When OlsG is co-expressed with the OL synthase OlsF in Escherichia coli, methylated OL derivatives are formed. An in vitro characterization shows that OlsG is responsible for the 3-fold methylation of the terminal d-nitrogen of OL. Methylation is dependent on the presence of the detergent Triton X-100 and the methyldonor S-adenosylmethionine

Effect of different gene inactivations on <i>arsA</i> gene expression measured by RT-qPCR.

<p>The level of the <i>arsA</i> transcripts was measured under encystment inducing conditions and it was normalized according to the level of the <i>gyrA</i> mRNA. The data are presented as fold change of <i>arsA</i> mRNA levels in mutants with <i>gacA</i>, <i>rsmZ1</i>, <i>rsmA</i>, and <i>gacA</i>-<i>rsmA</i> gene inactivations (strains SW5, SW13, SW11 and SW15), relative to those of the wild type strain (SW136). Determinations were made from bacterial cultures grown for 36 h in liquid BBOH medium at 30°C. The data represent the mean of triplicates and the error bars represent standard deviations. Asterisks indicate statistical significance (unpaired Student's <i>t</i>-test) in the comparison of each mutant versus the wild type strain, *P < 0.05.</p