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.

Evidence for conformational protection of nitrogenase against oxygen in Gluconacetobacter diazotrophicus by a putative FeSII protein.

The mechanisms protecting nitrogenase in Gluconacetobacter diazotrophicus from damage by oxygen were studied. Evidence is provided suggesting that in G. diazotrophicus these mechanisms include respiratory protection as well as conformational protection in which a putative FeSII Shethna protein is involved.

Glutamine synthetase from Acetobacter diazotrophicus: properties and regulation.

Glutamine synthetase from Acetobacter diazotrophicus, an endophyte originally isolated from sugarcane, was studied as a step in the identification of mechanisms underlying the role of A. diazotrophicus as a major supplier of fixed nitrogen to its host plant. The enzyme was purified and partially characterized.

[Blood neuronal specific enolase in newborns with perinatal asphyxia].

Introduction: Neuron-specific enolase (NSE) is a sensitive marker of brain injury after hypoxia or ischemia. There are few studies about its usefulness in asphyctic newborns.

Objective: To study the correlation between blood NSE levels and neurological outcome in newborns with hypoxic ischemic encephalopathy.

[Serum antibodies against hepatitis A virus among subjects of middle and low socioeconomic levels in urban area of Santiago, Chile].

Background: The epidemiology of hepatitis A virus (HAV) infection is closely associated to the level of hygiene and sanitation of the population. Newly industrialising areas experience a transition from high to intermediate endemicity, which is characterized by a shift in the exposure age to HAV, from early childhood to school ages or adolescence.

Aim: To measure the prevalence of HAV antibodies in subjects living in urban Santiago.

Clinical acceptability and immunogenicity of a pentavalent parenteral combination vaccine containing diphtheria, tetanus, acellular pertussis, inactivated poliomyelitis and Haemophilus influenzae type b conjugate antigens in two-, four- and six-month-old Chilean infants.

Background: In recent years additional parenteral vaccines have been recommended for routine immunization of infants in the US and elsewhere. The ability to administer multiple vaccines as a single injection without unacceptably increasing reactogenicity or decreasing immunogenicity of any component would offer many practical advantages.

Methods: A randomized, open, controlled trial was conducted to assess the tolerance profile and immunogenicity, as well as to identify potential antigenic interferences, resulting from administration of a parenteral combination vaccine for infants.

Serum apolipoproteins A-I and B in male and female full-term newborns of the Toledo study (Spain).

Cord serum apolipoproteins (Apo) A-I and B from 548 healthy, full-term singletons were studied. Females displayed slightly, but significantly, higher Apo A-I levels (p < 0.001) than males, particularly at weeks 38 and 39 (p < 0.

An unusual variant of chromosome 16. Two new cases.

Two new cases of an unusual chromosome 16 variant, 16p+, in non-related normal carriers are reported.

[Neonatal septic arthritis. Our experience in 14 cases (author's transl)].

A survey was carried out from october 1973 to december 1979 of fourteen newborn who presented septic arthritis secondary to sepsis, developed during their admission at our neonatology unit. Authors point out the high incidence of Klebsiella as the organism isolated in 48% of the positive cultures and the good response to general and local treatments. A discussion is done on the sequels and their long-term evolution.

[Transient neonatal diabetes (author's transl)].

A case of transient diabetes "mellitus" in a newborn infant with secondary hypertonic dehydration is presented. Authors review the problematical ethiology of this rare disease and a commentary is made on the adequate control of their case with continuous endovenous infusion of insulin.

Clinical bacteriological evaluation of infantile bacteriuria treated with fosfomycin.

The therapeutic action of fosfomycin has been studied in a group of 14 children, with simple and complicated infections of the urinary tract with congenital renal malformations. In the bacteriological study of the urine it was observed that the strains most frequently isolated were E. coli, Proteus sp.

[Bifid sternum. a case report (author's transl)].

A newborn with bifid sternum and early surgical management is reported.