Uptake and metabolic conversion of saturated and unsaturated fatty acids in Hep2 human larynx tumor cells

Research on fatty acid metabolism in cultured human larynx tumor cells Hep2 was carried out.The cells were incubated with either a saturated (palmitic) or a polyunsaturated (linoleic, alpha-linolenic and eicosatrienoic (n-6)) radioactive fatty acid (0.66 pM, 24 h). The best incorporation capacity was observed in the linoleic acid followed by alpha-linolenic, palmitic and eicosatrienoic acids. All fatty acids tested were anabolized to higher derivatives within their own family. Palmitic acid was primarily monodesaturated rather than elongated, proving to have a very active A9 desaturase activity.With respect to polyunsaturated acid metabolism, the conversion of alpha-linolenic acid to higher homologs, although better than linoleic acid, occurred far less efficiently than that observed in other non-highly undifferentiated human tumor cells. This impairment in higher polyunsaturated fatty acid biosynthesis, reflected in the low levels of arachidonic acid in the fatty acid composition, would not reside in the A5 desaturation step since Hep2 cells can readily convert eicosatrienoic acid into arachidonic acid. Considering the potential regulatory role of specific polyunsaturated fatty acids in the cell proliferative control, the knowledge of the metabolism of fatty acids in this human tumor cell would be important for designing future experiments in order to clarify the mechanism involved in balance, proliferation and cell death.     

Influence of one or two successive annual applications of organic fertilisers on the enzyme activity of a soil under barley cultivation

The effect of cow manure and two rates of addition of municipal solid waste (MSW) compost on the enzymatic activity of a soil supporting barley cultivation was studied and compared with mineral fertilisation (MF). The experiment was carried out in unirrigated land in field conditions for two years. One set of plots was fertilised only once, at the start of the experiment, while another set of plots was fertilised annually (before each sowing). In general, the organic amendments stimulated soil enzyme activity but mineral fertilisation did not. The annual addition of large quantities of MSW compost, in general, led to lower levels of enzyme activity than similar rates of amendment in the plots receiving a single addition, probably because of the toxic effect which the heavy metals incorporated with the MSW compost had on microbial development. In the second year, plot receiving a single application of organic amendment showed higher protease hydrolysing casein, beta-glucosidase and dehydrogenase activities than control or soil with mineral fertilisation. This implied that the addition of organic waste, and particularly MSW compost, had a catalysing effect in the soil which lasted for the following years. Barley yields obtained with organic amendments were, in general, similar to, or even higher, than those obtained with mineral fertilisation. The annual addition of high doses of compost had an inhibitory effect on enzyme activity and barley yield (compared with the results obtained with the low addition of compost) due to the negative effect of the heavy metals incorporated with the compost.     

First report of Lappetascaris lutjani Rasheed, 1965 (Nematoda, Ascaridoidea, Anisakidae) parasitizing Trachipterus arawatae (Pisces, Lampridiformes) on the Atlantic coast of Brazil

New host and geographical records are reported for the nematode Lappetascaris lutjani Rasheed, 1965, parasitizing the marine fish Trachipterus arawatae Clark, 1881 in Brazilian waters. Morphometric data and illustrations of the parasites are included.     

Integration of the cytogenetic and genetic linkage maps of Brassica oleracea

We have assigned all nine linkage groups of a Brassica oleracea genetic map to each of the nine chromosomes of the karyotype derived from mitotic metaphase spreads of the B. oleracea var. alboglabra line A12DHd using FISH. The majority of probes were BACs, with A12DHd DNA inserts, which give clear, reliable FISH signals. We have added nine markers to the existing integrated linkage map, distributed over six linkage groups. BACs were definitively assigned to linkage map positions through development of locus-specific PCR assays. Integration of the cytogenetic and genetic linkage maps was achieved with 22 probes representing 19 loci. Four chromosomes (2, 4, 7, and 9) are in the same orientation as their respective linkage groups (O4, O7, O8, and O6) whereas four chromosomes (1, 3, 5, and 8) and linkage groups (O3, O9, O2, and O1) are in the opposite orientation. The remaining chromosome (6) is probably in the opposite orientation. The cytogenetic map is an important resource for locating probes with unknown genetic map positions and is also being used to analyze the relationships between genetic and cytogenetic maps.     

Derivation and characterization of a dengue type 1 host range-restricted mutant virus that is attenuated and highly immunogenic in monkeys

We recently described the derivation of a dengue serotype 2 virus (DEN2mutF) that exhibited a host range-restricted phenotype; it was severely impaired for replication in cultured mosquito cells (C6/36 cells). DEN2mutF virus had selected mutations in genomic sequences predicted to form a 3' stem-loop structure (3'-SL) that is conserved among all flavivirus species. The 3'-SL constitutes the downstream terminal similar95 nucleotides of the 3' noncoding region in flavivirus RNA. Here we report the introduction of these same mutational changes into the analogous region of an infectious DNA derived from the genome of a human-virulent dengue serotype 1 virus (DEN1), strain Western Pacific (DEN1WP). The resulting DEN1 mutant (DEN1mutF) exhibited a host range-restricted phenotype similar to that of DEN2mutF virus. DEN1mutF virus was attenuated in a monkey model for dengue infection in which viremia is taken as a correlate of human virulence. In spite of the markedly reduced levels of viremia that it induced in monkeys compared to DEN1WP, DEN1mutF was highly immunogenic. In addition, DEN1mutF-immunized monkeys retained high levels of neutralizing antibodies in serum and were protected from challenge with high doses of the DEN1WP parent for as long as 17 months after the single immunizing dose. Phenotypic revertants of DEN1mutF and DEN2mutF were each detected after a total of 24 days in C6/36 cell cultures. Complete nucleotide sequence analysis of DEN1mutF RNA and that of a revertant virus, DEN1mutFRev, revealed that (i) the DEN1mutF genome contained no additional mutations upstream from the 3'-SL compared to the DEN1WP parent genome and (ii) the DEN1mutFRev genome contained de novo mutations, consistent with our previous hypothesis that the defect in DEN2mutF replication in C6/36 cells was at the level of RNA replication. A strategy for the development of a tetravalent dengue vaccine is discussed.     

Influence of the yeast strain on the changes of the amino acids,peptides and proteins during sparkling wine production by the traditional method

The influence of five yeast strains on the nitrogen fractions, amino acids, peptides and proteins, during 12 months of aging of sparkling wines produced by the traditional or Champenoise method, was studied. High-performance liquid chromatography (HPLC) techniques were used for analysis of the amino acid and peptide fractions. Proteins plus polypeptides were determined by the colorimetric Bradford method. Four main stages were detected in the aging of wines with yeast. In the first stage, a second fermentation took place; amino acids and proteins plus polypeptides diminished, and peptides were liberated. In the second stage, there was a release of amino acids and proteins, and peptides were degraded. In the third stage, the release of proteins and peptides predominated. In the fourth stage, the amino acid concentration diminished. The yeast strain used influenced the content of free amino acids and peptides and the aging time in all the nitrogen fractions. Received 25 March 2002/ Accepted in revised form 31 July 2002     

Status and metabolism of iron in elite sportsmen during a period of professional competition

The aim of this study was to determine the effect of both acute exercise and maintained training during a period of competition (3 mo, at the start of the season) on iron metabolism in sportsmen on a professional volleyball team. Twelve sportsmen volunteered for this study. The exercise test was performed on a mechanically braked Monark cycle ergometer and consisted of a triangular progressive test. Three blood samples were obtained in each test: at rest, just after exercise, and after recovery. The following hematological parameters were determined: red blood count (RBC), hemoglobin (Hb) and hematocrit (Hto), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), total proteins (TP), serum iron (Fe) and total iron-binding capacity (TIBC), ferritin (FER), transferrin (TRF), haptoglobin (HPT), and serum cortisol (COR) concentrations. We have found changes in hematological and biochemical variables related to Fe metabolism during the study. The changes observed could be the result of hemoconcentration processes after exercise and, at least in part, to physical stress and muscular damage. We conclude that athletes, after a period of adaptation, with a good plan of work/recovery series, undergo a biological redistribution on hematological and biochemical parameters concerning Fe metabolism during the training and competition period. Also, daily Fe supplementation could restore and mask the true repercussions of maintained training observed in other sports.     

Chronic hyperammonemia alters protein phosphorylation and glutamate receptor-associated signal transduction in brain

There is substantial evidence that hyperammonemia is one of the main factors contributing to the neurological alterations found in hepatic encephalopathy. The mechanisms by which chronic moderate hyperammonemia affects brain function involves alterations in neurotransmission at different steps. This article reviews the effects of hyperammonemia on phosphorylation of key brain proteins involved in neurotransmission (the microtubule-associated protein (MAP-2), Na+/K+-ATPase and NMDA receptors). The physiological function of these proteins is modulated by phosphorylation and its altered phosphorylation in hyperammonemia may contribute to impairment of neurotransmission. The effects of chronic hyperammonemia on signal transduction pathways associated to glutamate receptors, such as the glutamate-nitric oxide (NO)-cGMP pathway, are also reviewed. The possible contribution of the impairment of this pathway in brain in vivo to the neurological alterations present in patients with hepatic encephalopathy is discussed.