Moniliformin production byFusarium species isolated from Argentinian corn

Forty-one isolates ofFusarium obtained from the main Argentinian corn production area were tested for their ability to produce moniliformin. One of 22 isolates ofF. moniliforme, 2/10 of F.proliferatum and 3/9 ofF. subglutinans, produced moniliformin in a range between 0,3 to 2,7 mg/g. These data represent the first report of the production of moniliformin byFusarium species from section Liseola in Argentina.     

Continuous production of ethanol using yeast cells immobilized in preformed cellulose beads

 Saccharomyces cerevisiae cells were immobilized on preformed cellulose beads by adsorption. The fermentation capacity of the immobilized yeast cells was found to be practically independent of the hydrogen ion concentration between pH 3.1 and 6.25. The fermentation capacity was maximal at 30 °C. The immobilized yeast cells were used for continuous production of ethanol in a fluidized-bead reactor. The average values characteristic for the process were an ethanol concentration of 41.9±0.1 g l^-1, a fermentation efficiency of 82.9±2.1% and a volumetric productivity of 3.94±0.52 g l^-1 h^-1. Received: 9 October 1995/Accepted: 22 April 1996     

Cardiac phosphocreatine deficiency induced by GPA during postnatal development in rat

The effect of chronic administration of -guanidinopropionic acid (GPA) on the protein profiling, energy metabolism and right ventricular (RV) function was studied in the rat heart during the weaning and adolescence period. GPA was given in tap water (1–1.5%) using pair drink controls. The feeding of animals with GPA solution for a six week period resulted in elevation of heart to body weight ratio due to body growth retardation. GPA accumulated in the myocardium up to 67.37 ± 5.3 moles.g dry weight and the tissue content of total creatine, phosphocreatine and ATP was significantly decreased to 15%, 9% and 65% of control values respectively. Total activity of creatine kinase (CK) was not changed, but the proportion of mitochondrial (Mi) CK isoenzyme was decreased; the percentage of MB isoenzyme of CK was significantly higher. GPA treatment resulted in an elevation of the content of cardiac collagenous proteins and decrease of non-collagenous proteins in the heart; in parallel, a decrease of the collagen I to collagen III ratio was detected. The function of the RV was assessed using an isolated perfused heart with RV performing pressure-volume work. As compared to pair-drink controls, RV function was significantly impaired the GPA group: at any given right atrial filling pressure, the RV systolic pressure and the rate of pressure development were decreased by almost a factor of two. Elevation of the RV diastolic pressure with increasing pulmonary artery diastolic pressure was also significantly steeper in the GPA group which also showed decrease of cardiac output, especially at high outflow resistance. It may be assumed that chronic administration of GPA deeply influenced metabolic parameters, protein profiles and contractile function of the developing heart. On the other hand, concentrations of glucose, total lipids and triglycerides in blood plasma were not affected. All these data confirm the concept that the CK system is of central importance both for heart function and for the regulation of normal growth of cardiac myocytes.     

Vitamin A supplementation inhibits chemiluminescence and lipid peroxidation in isolated rat liver microsomes and mitochondria

In the present study we investigated if administration of vitamin A could protect rat liver microsomes and mitochondria from in vitro peroxidation. Appreciable decrease of chemiluminescence and lipid peroxidation was measured in microsomal membranes from rats receiving vitamin A, with respect to control animals. In membranes derived from control animals, the fatty acid composition was profoundly modified when subjected to in vitro peroxidation mediated by ascorbate-Fe⁺⁺, with a considerable decrease of 20:4 n6 and 22:6 n3 in mitochondria and 18:2 n6 and 20:4 n6 in microsomes. As a consequence the peroxidizability index, a parameter based on the maximal rate of oxidation of specific fatty acids was higher in supplemented animals than in control group when both kind of membranes were analyzed. These changes were less pronounced in membranes derived from rats receiving vitamin A. These results are in agreement with previous results that indicated that vitamin A may act as an antioxidant protecting membranes from deleterious effects.Abbreviations BHT butylated hydroxytoluene - BSA bovine serum albumin - CL chemiluminescence - PI peroxidizability index Member of Carrera del Investigador Científico, Consejo Nacional de Investigaciones Cientificas y Técnicas de la Republica Argentina     

Molecular evolution of the N-formyl peptide and C5a receptors in non-human primates

N-formyl peptides (FMLP) and complement fragment C5a are neutrophil chemoattractants. In humans, a single-copy gene was identified for the C5a receptor, and the receptor for FMLP (FPR1) is encoded by a single gene that shows 53% amino acid similarity to the C5aR. Two other humanFPR1 homologues,FPR-like 1 (FPR2/FPRL1) andFPR-like 2 (FPRL2) have been cloned. The human C5aR, FPR1, FPRL1, and FPRL2 are physically linked. By direct sequencing or by sequencing plasmid clones we studied theC5aR andFPR genes from four non-human primates (chimpanzee, gorilla, orangutan, and macaque). The sequences showed 95%–99% similarity to the human homologues, with the major divergences observed in macaque. In these genes, the transmembrane and the cytoplasmic domains are highly conserved, while the highest divergence corresponded to the extracellular loops involved in ligand binding. Additionally, we constructed a physical map of these genes in non-human primates. In all species the four genes were physically linked and we defined the relative orientation of the four genes in primates:C5aR>FPR1>FPR2 (FPRL1)>FPRL2. The nucleotide sequence data reported in this paper have been submitted to the EMBL/GenBank nucleotide sequence databases and have assigned the accession numbers X97730 (PTC5aR), X97731 (MMC5aR), X97732 (PPC5aR), X97730 (GGC5aR), X97734 (MMFPR1), X97735 (PPFPR1), X97736 (GGFPR1), X97737 (MMFPRL1), X97738 (GGFPRL1), X97739 (PTFPRL1), X97740 (MMFPRL2), X97741 (PPFPRL2), X97742 (GGFPRL2), X97743 (PTFPRL2), X97744 (PPFPRL1), and X97745 (PTFPR1)     

Variable influence of ferric and cupric ions on Saccharomyces cerevisiae strains used in asymmetric organic synthesis

Summary Fe (III) and Cu (II) each at 50 M in four commercial strains of Saccharomyces cerevisiae induced an increase of NAD(P)⁺ reduction in one strain (Turkish), but two others (Chilean and Brazilian), the presence of Fe(III) and/or Cu(II) diminished NAD(P)⁺ reduction presumably due to free radicais formation inside these living cells. Suprisingly, in the American strain, Fe(III) induced a decrease and Cu (II) an increase of NAD(P)⁺ reduction.     

Relationship between abundance of N2-fixing cyanobacteria and environmental features of Spanish rice fields

In order to estimate the potential utilization of N₂-fixing (heterocystous) cyanobacteria as natural biofertilizers in the Valencian rice fields (Spain), the distribution and seasonal variation of these microorganisms in water and sediment samples were evaluated, and the relationships among cyanobacterial abundance and physical and chemical characteristics of soil and water were investigated. N₂-fixing cyanobacteria were present in all the samples analyzed (25 sampling points sampled three times per year during two years). The relative cyanobacterial abundance in soil and water followed contrasting patterns, maximum presence in soil coincided with minimum abundance in water. Correlation analysis showed that cyanobacterial abundance in the two phases (water and sediment) was influenced more by water than by soil properties. Salinity, mineralization variables, and soluble reactive phosphate (SRP) correlated positively with heterocystous cyanobacteria presence. Furthermore, dissolved inorganic nitrogen (DIN) and the ratio DIN: SRP correlated negatively with cyanobacterial abundance. However DIN: SRP ratio better described the cyanobacterial distribution, with a threshold effect: below the Redfield ratio value (7.2 in mass units) cyanobacterial abundance was clearly higher. Correspondence to: A. Quesada.     

Sex masks: The double life of female commercial sex workers in Mexico City

The central topic of the article is the divided world of female commercial sex workers (FCSW) in Mexico City. Fourteen focus group sessions were conducted with 133 FCSW from varying socio-economic levels and types of work site, as well as seven individual interviews.FCSW live in a constant double bind, as mother and prostitute, and come into daily contact with society's double standard for women. Reactions include justifying sex work as a better paying employment opportunity for women, as a necessary evil, and as a type of social service, while at the same time hiding their profession from their families. FCSW also live out an archetypal female ambivalence, their selves divided between the mother/saint and the traitor/prostitute.This article defines elements which should be taken into account in culturally appropriate programs for prevention of HIV/AIDS transmission, especially the importance which FCSW give to their role as mothers and promotion of the condom as a physical and symbolic barrier between professional and private life.     

A DNA binding motif coordinating synthesis and degradation in proofreading DNA polymerases.

The functional significance of the conserved motif ''YxGG/A'', located between the 3''-5'' exonuclease and polymerization domains of eukaryotic-type DNA polymerases, has been studied by site-directed mutagenesis in phi29 DNA polymerase. Single substitutions at this region were obtained, and 11 phi29 DNA polymerase mutant derivatives were overproduced in Escherichia coli and purified to homogeneity. Nine mutants showed an altered polymerase/3''-5'' exonuclease balance on a template/primer DNA structure, giving rise to three different mutant phenotypes: (i) favored polymerization (high pol/exo ratio); (ii) favored exonucleolysis (low pol/exo ratio); and (iii) favored exonucleolysis and null polymerization. Interestingly, these three different phenotypes could be obtained by mutating a single amino acid at the ''YxGG/A'' motif. All different phenotypes could be directly related to defects in DNA binding at a particular active site. Thus, a high pol/exo ratio was related to a poor stability at the 3''-5'' exonuclease active site. On the contrary, a low pol/exo ratio or null polymerization capacity was related to a poor stability at the polymerization active site and either a normal or an increased accessibility to the exonuclease active site. These results allow us to propose that this motif, located in the connecting region between the N-terminal and C-terminal domains, has a primary role in DNA binding, playing a critical role in the coordination or cross-talk between synthesis and degradation.