Kinetic analysis of the assembly of the outer membrane protein LamB in Escherichia coli mutants each lacking a secretion or targeting factor in a different cellular compartment.

Outer membrane beta-barrel proteins in gram-negative bacteria, such as Escherichia coli, must be translocated from their site of synthesis in the cytoplasm to the periplasm and finally delivered to the outer membrane. At least a dozen proteins located in the cytoplasm, the periplasm, and both the inner and outer membranes are required to catalyze this complex assembly process. At normal growth temperatures and conditions the transport and assembly processes are so fast that assembly intermediates cannot be detected.

Rhizobium leguminosarum biovar viciae symbiotic hydrogenase activity and processing are limited by the level of nickel in agricultural soils.

Analysis of levels of hydrogenase processing and activity in Rhizobium leguminosarum biovar viciae bacteroids from pea (Pisum sativum) plants showed that the oxidation of nitrogenase-evolved hydrogen is limited by the availability of nickel in agricultural soils. This limitation was overcome by using an inoculant strain engineered for higher hydrogenase expression.

Genetics and biotechnology of the H(2)-uptake [NiFe] hydrogenase from Rhizobium leguminosarum bv. viciae, a legume endosymbiotic bacterium.

A limited number of strains belonging to several genera of Rhizobiaceae are capable of expressing a hydrogenase system that allows partial or full recycling of hydrogen evolved by nitrogenase, thus increasing the energy efficiency of the nitrogen fixation process. This review is focused on the genetics and biotechnology of the hydrogenase system from Rhizobium leguminosarum bv. viciae, a frequent inhabitant of European soils capable of establishing symbiotic association with peas, lentils, vetches and other legumes.

Craniofacial dyssynostosis: description of the first four Spanish cases and review.

Craniofacial dyssynostosis (CD) is characterized by premature fusion of the lambdoid and posterior part of the sagittal sutures, and short stature. Thus, the skull shape becomes dolichocephalic with protuberant forehead and either bulging or flat occiput. Facial changes are secondary to the skull defects, and some additional findings have also been described.

Identification of three genes encoding P(II)-like proteins in Gluconacetobacter diazotrophicus: studies of their role(s) in the control of nitrogen fixation.

In our studies on the regulation of nitrogen metabolism in Gluconacetobacter diazotrophicus, an endophytic diazotroph of sugarcane, three glnB-like genes were identified and their role(s) in the control of nitrogen fixation was studied. Sequence analysis revealed that one P(II) protein-encoding gene, glnB, was adjacent to a glnA gene (encoding glutamine synthetase) and that two other P(II) protein-encoding genes, identified as glnK1 and glnK2, were located upstream of amtB1 and amtB2, respectively, genes which in other organisms encode ammonium (or methylammonium) transporters. Single and double mutants and a triple mutant with respect to the three P(II) protein-encoding genes were constructed, and the effects of the mutations on nitrogenase expression and activity in the presence of either ammonium starvation or ammonium sufficiency were studied.