Independent induction of two blue light-dependent monovalent anion transport systems in the plasma membrane of Monoraphidium braunii

In the plasma membrane of the green alga Monoraphidium braunii there are at least two monovalent anion transport systems. One of them is specific for bicarbonate. This transport system is activated by blue light and its induction is triggered by a decrease in the external CO2 concentration. The second transport system is responsible for nitrate uptake at least. This transport system is also activated by blue light and its induction occurs when there is no ammonium in the external medium. Both transport systems are synthesized independently. Hence, when M. braunii cells grow with nitrate as the only nitrogen source under high CO2, they have a nitrate transport system but lack a bicarbonate transporter. Conversely, cells grown with ammonium under low CO2, have a bicarbonate transport system but lack a nitrate transporter. Both transport systems are induced in cells irradiated with white light in the absence of a carbon source, suggesting that there may be precursors in the plasma membrane that only need the synthesis and assembly of some component(s) to become fully active. The induction of nitrate and nitrite reductases, however, only takes place when a carbon source is supplied to the cells.     

Mechanisms of degradation of the fungal ornithine decarboxylase

Ornithine decarboxylase (ODC) is the first enzyme in polyamine biosynthesis in numerous living organisms, from bacteria to mammalian cells. Its control is under negative feedback regulation by the end products of the pathway. In dimorphic fungi, ODC activity and therefore polyamine concentrations are related to the morphogenetic process. From the fission yeast Schizosaccharomyces pombe to human, polyamines induce antizyme synthesis which in turn inactivates ODC. This is hydrolyzed by the 26S proteasome without ubiquitination. The regulatory mechanism of antizyme on polyamines is conserved, although to date no antizyme homology has been identified in some fungal species. The components that are responsible for regulating polyamine levels in cells and the current knowledge of ODC regulation in dimorphic fungi are presented in this review. ODC degradation is of particular interest because inhibitors of this pathway may lead to the discovery of novel antifungal drugs.     

Mitochondrial control of neuron death and its role in neurodegenerative disorders

Genetic or functional mitochondrial alterations can result in the initiation of cell death programs that are believed to contribute to cell death in diabetes, ageing and neurodegenerative disorders. Mitochondria are being considered the main link between cellular stress signals activated during acute and chronic nerve cell injury, and the execution of nerve cell death. This second function of mitochondria is regulated by several families of proteins that can trigger an increase in permeability of the outer and/or inner mitochondrial membrane. One example of this is the formation of the mitochondrial permeability transition pore (MPTP). This process can trigger the release of cell death-inducing factors from mitochondria, as well as a dissipation of the mitochondrial transmembrane potential, depletion of ATP, and increased free radical formation. Among the factors released from mitochondria are cytochrome c, the apoptosis inductor factor (AIF), and caspases. We review the role of the MPTP in diverse physiological and pathological processes, including neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis (ALS). The design of drugs that could interfere with the functions of the MPTP could allow novel therapeutic approaches for the treatment of acute and chronic nerve cell injury.     

Intraspecific characterization of Vibrio alginolyticus isolates recovered from cultured fish in Spain

AIMS: Intraspecific differentiation and characterization of Vibrio alginolyticus strains isolated from cultured fish in Spain. MATERIALS AND RESULTS: Thirty-four Vibrio alginolyticus strains isolated from cultured fish were intraspecifically characterized on the basis of biochemical and exoenzymatic patterns, outer membrane protein (OMP) profiles, ribotyping and plasmid analyses. The typing methods used did not allow to group V. alginolyticus isolates on the basis of their sources of collection. A higher homogeneity was observed in OMP profiles. A high percentage of isolates were plasmidless. Ribotyping was the highest discriminatory typing method, as all the isolates tested presented 23 profiles using the HindIII restriction enzyme. On the basis of the ribotyping pattern, a similarity matrix and a dendrogram were constructed. CONCLUSIONS: The results obtained indicate that V. alginolyticus strains isolated from southwestern Spain belong to different clonal lineages. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has shown differences with other similar studies carried out in other areas of Europe with strains of V. alginolyticus with respect to the clonal lineages of the strains isolated in southwestern Spain.     

Resolution of parallel and antiparallel oligonucleotide triple helices formation and melting processes by multivariate curve resolution

A procedure is described for the complete resolution of concentration profiles of oligonucleotide triplexes as a function of pH and temperature. The pH and temperature ranges at which triplexes are present and the relative concentrations of all the species involved in acid-base and conformational equilibria are successfully estimated from Multivariate Curve Resolution analysis of UV absorbance spectra recorded along acid-base titrations and melting experiments of single stranded, hairpin and their mixtures. The dependence of formation constants upon pH was successfully estimated. The hairpin h26 (5'-GAAGGAGGAGA-TTTT-TCTCCTCCTTC-3'), and the single stranded oligonucleotides s11CT (5'-CTTCCTCCTCT-3'), s11AG (5'-AGAGGAGGAAG-3') and s11TG (5'-TGTGGTGGTTG-3') were synthesized and their protonation and conformational equilibria were studied in detail. The procedure was shown to be especially useful for the study of triplexes with a low hypochromism upon formation.     

Algorithm of hair restoration surgery in children

Hair is an inseparable element of external appearance of every human being. Although various fashion trends come and go, the lack of hair is for many a major aesthetic and psychological problem. Even if men's balding can be accepted as a natural phenomenon, hair loss in children is considered to be a condition demanding correction. During an 18-year period, 8440 hair restoration operations were performed at the Hair Clinic Poznan, in Poznan, Poland. Most patients were men treated for androgenic alopecia. Among the patients were 57 children in whom hair loss resulted from hereditary factors, perinatal traumas, radiotherapy, and mechanical, thermal, and chemical damage. Methods of restoration were adjusted to type of hair loss, patient age, and ability to cooperate with the surgeon. In cases of single massive scars, skin flap correction was usually used. The flaps were prepared with the use of expanders. In cases of numerous scattered defects or considerable thinning of the scalp, the method of choice was hair transplantation. The "four-hand stick-and-place" technique developed by the authors enabled the surgeon to quickly and precisely carry out the procedure. Application of varied surgery techniques in scalp reconstruction procedures in children gave very good aesthetic results with a minimal complication rate.     

Influence of boron and calcium on the tolerance to salinity of nitrogen-fixing pea plants

The effects of different levels of B (from 9.3 to 93 M B) and Ca (from 0.68 to 5.44 mM Ca) on plant development, nitrogen fixation, and mineral composition of pea (Pisum sativum L. cv. Argona) grown in symbiosis with Rhizobium leguminosarum bv. viciae 3841 and under salt stress, were analysed. The addition of extra B and extra Ca to the nutrient solution prevented the reduction caused by 75 mM NaCl of plant growth and the inhibition of nodulation and nitrogen fixation. The number of nodules recovered by the increase of Ca concentration at any B level, but only nodules developed at high B and high Ca concentrations could fix nitrogen. Addition of extra B and Ca during plant growth restored nodule organogenesis and structure, which was absolutely damaged by high salt. The increase in salt tolerance of symbiotic plants mediated by B and Ca can be co-related with the recovery of the contents of some nutrients. Salinity produced a decrease of B and Ca contents both in shoots and in nodulated roots, being increased by the supplement of both elements in the nutrient solution. Salinity also reduced the content in plants of other nutrients important for plant development and particularly for symbiotic nitrogen fixation, as K and Fe. A balanced nutrition of B and Ca (55.8 M B, 2.72 mM Ca) was able to counter-act the deficiency of these nutrients in salt-stressed plants, leading to a huge increase in salinity tolerance of symbiotic pea plants. The necessity of nutritional studies to successfully cultivate legumes in saline soils is discussed and proposed.