Carta del trabajador autogestionario

La sociedad capitalista ha sufrido profundas transformaciones. Mientras que los Tratados Internacionales y los Textos Constitucionales aseguran “el Derecho al Trabajo” y a “Condiciones Dignas de trabajo”, los mercados y las políticas públicas en América latina y el mundo, conducen a la informalidad y el desempleo de la mayor parte de la población. Hoy es absolutamente insuficiente la categoría jurídica del “trabajo dependiente” como única contrapartida al “trabajo autónomo”, porque no describe a toda la realidad. Los trabajadores se organizan y se asocian para reproducir su vida y la de su familia, y lo hacen recurriendo a la solidaridad, a la reciprocidad y a la redistribución, en el ámbito de Organizaciones de la “Economía Social, Solidaria y Popular”. Para luchar por su Derecho al Trabajo y a una Vida Digna, organizan empresas sin capitalistas que las financien y se apropien de su producido, o recuperan empresas que naufragaron en el mercado. Autogestionan asociados una empresa de su propiedad, a la que administran y gestionan, y cuyo producido les pertenece. Es imprescindible que el Derecho al Trabajo incorpore “el Trabajo Autogestionado y Coordinado”, como categoría diferente a la del trabajo “dependiente” y al “trabajo autónomo”, y que asegure para “todos los trabajadores” un piso de Derechos Económicos, Sociales y Culturales. Esta Carta es un aporte para la construcción de la categoría jurídica del “Trabajador Autogestionado”, y un derrotero para la progresiva vigencia de los Derechos Sociales, Económicos y Culturales, que los Pactos y Convenios Internaciones les asignan. En una segunda parte de esta carta se desarrolla un proyecto para habilitar el debate de algunos aspectos centrales que debería tener una legislación que regule las especificidades de una Cooperativa de Trabajo asociado, en el marco de una realidad argentina compleja.Fil: Shujman, Mario Saul. Universidad Nacional de Rosario. Argentin

Role of an Essential Acyl Coenzyme A Carboxylase in the Primary and Secondary Metabolism of Streptomyces coelicolor A3(2)

Two genes, accB and accE, that form part of the same operon, were cloned from Streptomyces coelicolor A3(2). AccB is homologous to the carboxyl transferase domain of several propionyl coezyme A (CoA) carboxylases and acyl-CoA carboxylases (ACCases) of actinomycete origin, while AccE shows no significant homology to any known protein. Expression of accB and accE in Escherichia coli and subsequent in vitro reconstitution of enzyme activity in the presence of the biotinylated protein AccA1 or AccA2 confirmed that AccB was the carboxyl transferase subunit of an ACCase. The additional presence of AccE considerably enhanced the activity of the enzyme complex, suggesting that this small polypeptide is a functional component of the ACCase. The impossibility of obtaining an accB null mutant and the thiostrepton growth dependency of a tipAp accB conditional mutant confirmed that AccB is essential for S. coelicolor viability. Normal growth phenotype in the absence of the inducer was restored in the conditional mutant by the addition of exogenous long-chain fatty acids in the medium, indicating that the inducer-dependent phenotype was specifically related to a conditional block in fatty acid biosynthesis. Thus, AccB, together with AccA2, which is also an essential protein (E. Rodriguez and H. Gramajo, Microbiology 143:3109–3119, 1999), are the most likely components of an ACCase whose main physiological role is the synthesis of malonyl-CoA, the first committed step of fatty acid synthesis. Although normal growth of the conditional mutant was restored by fatty acids, the cultures did not produce actinorhodin or undecylprodigiosin, suggesting a direct participation of this enzyme complex in the supply of malonyl-CoA for the synthesis of these secondary metabolites

Time-Resolved in Situ Synchrotron X-ray Diffraction Studies of Type 1 Silicon Clathrate Formation

Silicon clathrates are unusual open-framework solids formed by tetrahedrally bonded silicon that show remarkable electronic and thermal properties. The type I structure has a primitive cubic unit cell containing cages occupied by metal atoms to give compositions such as Na8Si46 and Na2Ba6Si46. Although their structure and properties are well described, there is little understanding of the formation mechanism. Na8Si46 is typically produced by metastable thermal decomposition under vacuum conditions from NaSi, itself an unusual structure containing Si44– polyanions. In this study, we used in situ synchrotron X-ray diffraction combined with rapid X-ray detection on samples taken through a controlled temperature ramp (25–500 °C at 8 °C/min) under vacuum conditions (10–4 bar) to study the clathrate formation reaction. We also carried out complementary in situ high-temperature solid-state 23Na NMR experiments using a sealed tube loaded under inert-gas-atmosphere conditions. We find no evidence for an intermediate amorphous phase during clathrate formation. Instead, we observe an unexpectedly high degree of structural coherency between the Na8Si46 clathrate and its NaSi precursor, evidenced by a smooth passage of several X-ray reflections from one structure into the other. The results indicate the possibility of an unusual, epitaxial-like, growth of the clathrate phase as Na atoms are removed from the NaSi precursor into the vacuum