d-Glucose uptake in germinating wild-type Aspergillus nidulans conidia is an energy-requiring process mediated by at least two transport systems of differing affinities for glucose: a low-affinity system (K m∼1·4 mM) and a high-affinity system (K m∼16 μM). The low-affinity system is inducible by glucose; the high-affinity system is subject to glucose repression effected by the carbon catabolite repressor CreA and is absent in sorA3 mutant conidia, which exhibit resistance to l-sorbose toxicity. An intermediate-affinity system (K m∼400 μM) is present in sorA3 conidia germinating in derepressing conditions. creA derepressed mutants show enhanced sensitivity to l-sorbose. The high-affinity uptake system appears to be responsible for the uptake of this toxic sugar.

The mstE gene encoding a low affinity glucose transporter active during the germination of Aspergillus nidulans conidia on glucose medium has been identified. mstE expression also occurs in hyphae, is induced in the presence of other repressing carbon sources besides glucose, and is dependent on the function of the transcriptional repressor CreA. The expression of MstE and its subcellular distribution have been studied using a MstE-sGFP fusion protein.Concordant with data on mstE expression, MstE-sGFP is synthesized in the presence of repressing carbon sources, and fluorescence at the periphery of conidia and hyphae is consistent with MstE location in the plasma membrane. Deletion of mstE has no morphological phenotype but results in the absence of low affinity glucose uptake kinetics, the latter being substituted by a high affinity system.For many filamentous fungi, the principal source of nutrients in the natural environment is dead and decaying plant material. Plant cell walls consist of two structural phases: the microfibrillar phase, the bulk of which is cellulose, and the much more heterogeneous matrix phase of which pectins and hemicelluloses are among the major constituents (1). Organic carbon is obtained from these materials by virtue of the action of cellulolytic enzymes secreted by the fungus that digest these polymers, resulting in the liberation of smaller compounds that can be assimilated. Studies in various filamentous fungi have shown that enzyme production is regulated in such a way that the nature of the activities secreted is appropriate for effective utilization of the substrate available, and whereas the monosaccharides released are principal sources of carbon and energy, they also play important roles in the induction and repression of gene expression (Ref. 2 and references therein). In this regard the identification and characterization of the genes that encode catabolic enzymes and, in particular, their regulation have been major research interests for several decades, and relatively little attention has been focused on the fundamental physiological process of monosaccharide uptake in the filamentous fungi.Previous analyses of sugar uptake kinetics in the model filamentous fungi Aspergillus nidulans and Neurospora crassa provided evidence for the existence of energy consuming, carrier-mediated transport systems for D-glucose and some other sugars (3-7). In contrast, studies conducted by a number of groups in the model yeast Saccharomyces cerevisiae ultimately concluded that monosaccharide uptake was effected by at least two facilitated diffusion systems, whereas the uptake of disaccharides required the expenditure of energy (Refs. 8 and 9 and references therein). The identification of hexose transporter genes in yeast commenced with the isolation of the sucrose non-fermenting mutant snf3 (10) followed by the characterization of the SNF3 gene (11) and progressed by various means until its rapid conclusion upon analysis of the whole yeast genome data (12, 13). A total of 34 proteins compris...

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Independent systems of high and low affinity effect glucose uptake in the filamentous fungus Aspergillus nidulans. Low-affinity uptake is known to be mediated by the product of the mstE gene. In the current work two genes, mstA and mstC, have been identified that encode high-affinity glucose transporter proteins. These proteins' primary structures share over 90% similarity, indicating that the corresponding genes share a common origin. Whilst the function of the paralogous proteins is little changed, they differ notably in their patterns of expression. The mstC gene is expressed during the early phases of germination and is subject to CreA-mediated carbon catabolite repression whereas mstA is expressed as a culture tends toward carbon starvation. In addition, various pieces of genetic evidence strongly support allelism of mstC and the previously described locus sorA. Overall, our data define MstC/SorA as a high-affinity glucose transporter expressed in germinating conidia, and MstA as a high-affinity glucose transporter that operates in vegetative hyphae under conditions of carbon limitation.

Neonatal sepsis is a major cause of morbidity and mortality in neonatal intensive care units. Treatment with antibiotics reduces mortality and morbidity, but neonatal sepsis remains a serious life-threatening condition. The objective of this study was to evaluate cognitive impairment in adult mice submitted to sepsis in the neonatal period. To this aim, 2-day-old male C57BL/6 mice were submitted to sepsis by injection of 25 μg of LPS. Sixty days after, the learning and memory were evaluated. It was observed that the mice submitted to neonatal sepsis presented impairment of habituation, aversive, and object recognition memories, and had an increase of immobility time in forced swimming test in adulthood. In conclusion, this study shows that the neonatal sepsis causes long-term brain alterations. These alterations can persist to adulthood in an animal model due to a vulnerability of the developing brain.

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OBJECTIVE: evaluated the involvement of NLRP3 inflammasome in schizophrenia-like behavior in young animals exposed to MIA. METHODS: To this aim, on the 15th gestational day, the females received an injection of lipopolysaccharides. When the animals completed 7, 14 and 45 postnatal days, they were killed and the whole brain was dissected for biochemical analysis. Animals with 45 postnatal days were submitted to behavioral tests of locomotor activity, social interaction and stereotyped movements. RESULTS: It was observed that the animals presented schizophrenia-like behavior at 45 postnatal days associated to the increased of NLRP3 inflammasome expression and IL-1β levels on 7, 14 and 45 postnatal days. CONCLUSION: This study show that MIA may be associated with a schizophrenia-like behavior. This behavior can be induced to a neuroinflamatory profile in brain. These evidences may base future studies on the relationship between neuroinflammation and psychiatric disorders.

Cerebral monitoring constitutes an emerging issue in perinatal medicine. Near Infrared Spectroscopy (NIRS) monitors brain oxygenation status in sick infants although data in healthy infants are lacking. The present study investigates whether NIRS parameters change according to gestational age and correlate with S100B protein. We recruited 64 healthy newborns (weeks' gestation: 30-42 wks) in which we performed in the first 6-hours after birth routine clinical, radiological and laboratory variables, cerebral oxygen saturation (rSO2), fractional cerebral tissue oxygen extraction (FTOE) values and S100B urine assessment. rSO2 and FTOE correlated (R=-0.73; R=0.51; P less than 0.01, for both) with gestational age. Highest rSO2 and the lowest FTOE peaks (P less than 0.001) were found at 30-33 wks. From 34 wks onwards, rSO2 progressively decreased and FTOE increased reaching their lower dip/peak (P less than 0.001) at 38-39 weeks. A significant correlation between S100B and NIRS parameters (rSO2: r=0.77; FTOE: r=-0.69; P less than 0.01) has been found. The present study shows that NIRS parameters and S100B protein correlation may be of help in brain function monitoring.