Microphytobenthos assemblage mapping by spatial visible-infrared remote sensing in a shellfish ecosystem

The aim of this work is to assess the use of (SPOT) multispectral visible infrared remote sensing to study microphytobentos assemblages in a shellfish ecosystem (Bay of Bourgneuf, France). SPOT satellite images (acquired at low tide in spring or autumn between 1986 and 1998) were calibrated using in situ radiometric data, and the normalised vegetation index (NDVI) obtained from these images showed microphytobenthos on bay mudflats. Proliferation was mainly along a north-south strip, essentially localised around the +2 m isobath and covering a surface area of 19 to 25% of the total mudflat area studied (420 to 550 ha). Three factors seem to be responsible for the spatial structure of the assemblages: bathymetry, nutrient input from the Falleron River and its channel, and the location of oyster-farming areas. Although spatial and spectral resolutions of multispectral remote sensing data have certain limitations, this approach opens up a new field of application for hyperspectral remote sensing, particularly for synoptic mapping of biomass distribution.     

Heterologous protein production and delivery systems for Lactococcus lactis

Lactic acid bacteria (LAB), widely used in the food industry, are present in the intestine of most animals, including humans. The potential use of these bacteria as live vehicles for the production and delivery of heterologous proteins of vaccinal, medical or technological interest has therefore been extensively investigated. Lactococcus lactis, a LAB species, is a potential candidate for the production of biologically useful proteins. Several delivery systems have been developed to target heterologous proteins to a specific cell location (i.e., cytoplasm, cell wall or extracellular medium). A promising application of L. lactis is its use as an antigen delivery vehicle, for the development of live mucosal vaccines. The expression of heterologous proteins and antigens as well as the various delivery systems developed in L. lactis, and its use as an oral vaccine carrier are discussed.     

Alpha-oxo semicarbazone peptide or oligodeoxynucleotide microarrays

We describe in this paper the preparation and characterization of semicarbazide glass slides and their use for the fabrication of microarrays using site-specific alpha-oxo semicarbazone ligation. The functional density and homogeneity of the semicarbazide glass slides were optimized by analyzing the reactivity of the layer toward a synthetic glyoxylyl fluorescent probe. Oligonucleotide microarrays were prepared by site-specific immobilization of glyoxylyl oligodeoxynucleotides. The slides were directly used in the hybridization assays using fluorescence detection and displayed a significant gain in sensibility as compared to the aldehyde glass slide/amino oligodeoxynucleotide chemistry. Semicarbazide slides were also used for the immobilization of a biotinylated peptide alpha-oxo aldehyde. The peptide microarrays allowed model interaction studies with streptavidin or an anti-biotin antibody.     

Synthesis and properties of oligonucleotides involving a perylene unit linked to a 2'-deoxyribose residue

We report here the synthesis and binding properties of oligonucleotides involving a perylene unit linked to the anomeric position of a 2'-deoxyribose residue. Both anomers were separated and incorporated separately at either the 5'-end or the internal position of a pyrimidine sequence. In any case the presence of the perylene unit stabilizes the complexes formed with either the single or the double-stranded target.     

Hyperplasia of adrenal rest tissue causing a retroperitoneal mass in a child with 11 beta-hydroxylase deficiency

We report the case of a child with congenital adrenal hyperplasia due to 11 beta-hydroxylase deficiency, with hyperplasia of adrenal rest tissue presenting as a retroperitoneal mass. Complete resolution of the mass was noted after 18 months of hydrocortisone replacement therapy.     

Structure-activity relationship in the oxazolidinone-quinolone hybrid series: influence of the central spacer on the antibacterial activity and the mode of action

Oxazolidinone-quinolone hybrids, which combine the pharmacophores of a quinolone and an oxazolidinone, were synthesised and shown to be active against a variety of susceptible and resistant Gram-positive and Gram-negative bacteria. The nature of the spacer greatly influences the antibacterial activity by directing the mode of action, that is quinolone- and/or oxazolidinone-like activity. The best compounds in this series have a balanced dual mode of action and overcome all types of resistance, including resistance to quinolones and linezolid, in clinically relevant Gram-positive pathogens.     

Transgenic Arabidopsis plants can accumulate polyhydroxybutyrate to up to 4% of their fresh weight

 Transgenic Arabidopsis thaliana (L.) Heynh. plants expressing the three enzymes encoding the biosynthetic route to polyhydroxybutyrate (PHB) are described. These plants accumulated more than 4% of their fresh weight (≈40% of their dry weight) in the form of PHB in leaf chloroplasts. These very high producers were obtained and identified following a novel strategy consisting of a rapid GC-MS analysis of a large number of transgenic Arabidopsis plants generated using a triple construct, thus allowing the parallel transfer of all three genes necessary for PHB synthesis in a single transformation event. The level of PHB produced was 4-fold greater than previously published values, thus demonstrating the large potential of plants to produce this renewable resource. However, the high levels of the polymer produced had severe effects on both plant development and metabolism. Stunted growth and a loss of fertility were observed in the high-producing lines. Analysis of the metabolite composition of these lines using a GC-MS method that we have newly developed showed that the accumulation of high levels of PHB was not accompanied by an appreciable change in either the composition or the amount of fatty acids. Substantial changes were, however, observed in the levels of various organic acids, amino acids, sugars and sugar alcohols. Received: 2 February 2000 / Accepted: 31 March 2000     

Direct Calculation of a Tree Length Using a Distance Matrix

Comparative studies of tree-building methods have shown minimum evolution to be in general an accurate criterion for selecting a true tree. To improve the use of this criterion, this paper proposes a method for rapidly and directly calculating a length of a dichotomous tree without having to resort to branch length calculations. This direct calculation (DC) method applies to the complete final topology, giving equal importance to each branch after a dichotomy. According to this method, the tree length S _DC is S _DC =∑ _i ∑ _j (D _ij /2 ^Bij ) = (∑ _i<j ∑D _ij 2 ^Bmax−Bij )/2 ^{Bmax −1} where D _ij is the observed distance between taxa i and j, B _ij is the number of branches connecting i and j, Bmax is the greatest B _ij in the tree, and the powers of two are due to the dichotomy of the tree. This tree length expression may be used as a rapid method for selecting the shortest tree from a set of hypothetical or subobtimal trees. Received: 2 March 2000 / Accepted: 24 March 2000     

Yield, chemical composition and gel strength of agarocolloids of Gracilaria gracilis, Gracilariopsis longissima and the newly reported Gracilaria cf. vermiculophylla from Roscoff (Brittany, France)

Agarocolloids were extracted from field samples of Gracilaria gracilis, Gracilariopsis longissima and the newly reported Gracilaria cf. vermiculophylla harvested at different periods of the year near Roscoff (France). Native and alkali modified extracts were characterized by GLC, HPLC and FT-IR spectroscopy. The main components of agarocolloids isolated by freeze-thawing method, were 3,6-anhydrogalactose and galactose. In addition, minor components (6-O-methyl-galactose, 4-O-methyl-galactose and sulfate groups ranging from 4.4 up to 6.6% [w/w]) were detected. The highest rate of 6-O-methylgalactose was observed in agarocolloids from vermiculophylla (14 mole%). Sulfates were mainly branched on C4 of the D-galactose in gracilis and Gs. longissima agarocolloids. G. vermiculophylla agaroids isolated by EtOH and NaCl precipitations from the syneresis water were characterized by a high sulfation on C6 of galactose and a low sulfation on C2 of 3,6-anhydrogalactose. Native agarocolloid gel strengths from Gracilaria species were clearly higher than those of Gracilariopsis. Alkali treatments reduced the sulfate levels but increased slightly the gel strengths. An approximation of the polymer sizes carried out with colorimetric assays indicated that the polymer sizes were higher in G. gracilis than observed in Gs. longissima. This revised version was published online in June 2006 with corrections to the Cover Date.