A randomized study was conducted to evaluate the effects of single-dose and daily vitamin D supplementation in pregnant women during the last trimester of a winter pregnancy in the Northwest of France. The women were divided into three randomized groups: one (N = 21) was given a vitamin D2 supplement of 1000 IU/day during the last three months of pregnancy, one (N = 27) was given a single oral dose of 5 mg at the seventh month of pregnancy, and one (N = 29) acted as a control. Venous plasma samples were obtained at delivery from the women and from cord blood, and levels of calcium, 25-OHD, and 1,25(OH)2D were determined. No significant difference in plasma calcium concentration was found among the three groups, but within each group plasma calcium concentrations were higher in the cord samples than in the respective maternal samples. The levels of the two metabolites measured were consistently lower in the cord samples than in the respective maternal samples. Cord 25-OHD concentrations correlated with those of maternal plasma. No significant modification of maternal calciuria or of the birth weight of term infants was observed. 25-OHD concentrations were greater in maternal and cord plasma from treated mothers, but only a slight difference was observed between the supplemented groups. 1,25(OH)2D concentrations were not significantly different in the three groups. A single 5-mg dose of vitamin D given orally at the seventh month of pregnancy provides effective prophylaxis in the authors' region.

Diatoms are marine organisms that represent one of the most important sources of biomass in the ocean, accounting for about 40% of marine primary production, and in the biosphere, contributing up to 20% of global CO2 fixation. There has been a recent surge in developing the use of diatoms as a source of bioactive compounds in the food and cosmetic industries. In addition, the potential of diatoms such as Phaeodactylum tricornutum as cell factories for the production of biopharmaceuticals is currently under evaluation. These biotechnological applications require a comprehensive understanding of the sugar biosynthesis pathways that operate in diatoms. Here, we review diatom glycan and polysaccharide structures, thus revealing their sugar biosynthesis capabilities.

Roots are important organs for plant survival. In recent years, clear differences between roots and shoots in their respective plant defense strategies have been highlighted. Some putative gene markers of defense responses usually used in leaves are less relevant in roots and are sometimes not even expressed. Immune responses in roots appear to be tissue-specific suggesting a compartmentalization of defense mechanisms in root systems. Furthermore, roots are able to activate specific defense mechanisms in response to various elicitors including Molecular/Pathogen Associated Molecular Patterns, (MAMPs/PAMPs), signal compounds (e.g., hormones) and plant defense activator (e.g., β-aminobutyric acid, BABA). This review discusses recent findings in root defense mechanisms and illustrates the necessity to discover new root specific biomarkers. The development of new strategies to control root disease and improve crop quality will also be reviewed.

In accordance with previous results, the activity of extracellular proteases from Pseudomonas fluorescens MFO is maximal at a growth temperature of 17.5°C, well below the optimal growth temperature. In addition, the activities of three periplasmic phosphatases display the same growth temperature optimum. Chemostat experiments have shown that it is the growth temperature itself and not the value of the growth rate that regulates these activities. In contrast, a foreign periplasmic phosphatase, expressed under the control of its own promoter, displays a different sensitivity toward temperature. We conclude that in the psychrotrophic strain P. fluorescens MFO, growth temperature exerts a specific control upon the activity of certain enzymes. The critical temperature (17.5C) is within the range of normal growth, suggesting that this control is probably different from a cold shock or heat shock response.Pseudomonas fluorescens is well known as a major psychrotrophic contaminant of raw milk stored in refrigerated tanks (16). Many studies of this bacterium have been concerned with the production of deleterious extracellular enzymes, such as thermostable proteases (8,15,27). Among the numerous observations concerning these enzymes, it has been repeatedly shown that most strains maximally produce proteases at a temperature (15 to 20°C) well below the optimal growth temperature (25 to 30°C) (13,19,25). However, no studies have yet dealt with the mechanism of regulation of protease production with regard to temperature.At this stage two main questions can be raised regarding the elucidation of this mechanism. The first one relates to the specificity of this temperature effect, i.e., whether it is restricted to the production of proteases or extended to the production of other enzymes. To this end, the activities of extracellular proteases as a function of growth temperature were compared with those of several periplasmic phosphatases. The exported enzymes all showed the same regulation by temperature even though they are clearly differentially regulated by other growth conditions. Thus, it was important to determine whether this temperature effect might involve protein export through the cytoplasmic membrane. If so, any foreign exported protein should be submitted to the same effect. The expression of a gene from the mesophilic species Escherichia coli, under the control of its own promoter, was studied in P. fluorescens at different growth temperatures. In this case, a temperature effect similar to that observed with the native enzymes was not demonstrated.The second question is whether the temperature itself is the direct cause of the regulation or an indirect effector acting through the growth rate variation; such an indirect effect has indeed been demonstrated for several activities or proteins in mesophilic bacteria (5). To answer this question, the activities of the two acidic phosphatases were assayed in cells grown in a chemostat at two different temperatures and * Corresponding author. several dilution rates. The ...

In the psychrotrophic bacterium Pseudomonas fluorescens, the production of several enzymes that otherwise differ in their cell location, growth phase production and inducibility appeared to be similarly regulated by the growth temperature. In order to determine the level of this regulation, the expression of the apo and lip genes encoding two of these enzymes, the acidic phosphatase and lipase, respectively, was studied at different temperatures. Both genes were optimally expressed at 17.5 degrees C, i.e., at the optimal temperature of production of the enzymes; however, the low level of activity at the highest temperature could be due to an additional post-transcriptional control.

The psychrotrophic bacterium Pseudomonas fluorescens is a milk contaminant known to secrete a lipase that is a nuisance for the dairy industry but may have a biotechnological interest. Strain MF0 secretes this enzyme upon induction under various conditions. Regardless of the inducer and growth temperature, a single enzyme is produced. However, optimal production occurs when the culture is grown at 17.5 ° C. Other exported proteins (an extracellular protease and two periplasmic phosphatases) have previously been shown to display exactly the same optimal temperature of production. In contrast, constitutive cell-bound esterase and cytochrome oxidase are produced at a roughly constant rate regardless of the growth temperature. The relevance of these results are discussed in terms of multifunctional regulation and interest for the dairy industry.

Background and Aims Extensins are hydroxyproline-rich glycoproteins thought to strengthen the plant cell wall, one of the first barriers against pathogens, through intra- and intermolecular cross-links. The glycan moiety of extensins is believed to confer the correct structural conformation to the glycoprotein, leading to self-assembly within the cell wall that helps limit microbial adherence and invasion. However, this role is not clearly established. Methods We used Arabidopsis thaliana mutants impaired in extensin arabinosylation to investigate the role of extensin arabinosylation in root–microbe interactions. Mutant and wild-type roots were stimulated to elicit an immune response with flagellin 22 and immunolabelled with a set of anti-extensin antibodies. Roots were also inoculated with a soilborne oomycete, Phytophthora parasitica, to assess the effect of extensin arabinosylation on root colonization. Key Results A differential distribution of extensin epitopes was observed in wild-type plants in response to elicitation. Elicitation also triggers altered epitope expression in mutant roots compared with wild-type and non-elicited roots. Inoculation with the pathogen P. parasitica resulted in enhanced root colonization for two mutants, specifically xeg113 and rra2. Conclusions We provide evidence for a link between extensin arabinosylation and root defence, and propose a model to explain the importance of glycosylation in limiting invasion of root cells by pathogenic oomycetes.

Although Phaeodactylum tricornutum is gaining importance in plant molecular farming for the production of high-value molecules such as monoclonal antibodies, little is currently known about key cell metabolism occurring in this diatom such as protein glycosylation. For example, incorporation of fucose residues in the glycans N -linked to protein in P. tricornutum is questionable. Indeed, such epitope has previously been found on N -glycans of endogenous glycoproteins in P. tricornutum . Meanwhile, the potential immunogenicity of the α(1,3)-fucose epitope present on plant-derived biopharmaceuticals is still a matter of debate. In this paper, we have studied molecular actors potentially involved in the fucosylation of the glycoproteins in P. tricornutum. Based on sequence similarities, we have identified a putative P. tricornutum GDP- L -fucose transporter and three fucosyltransferase (FuT) candidates. The putative P. tricornutum GDP- L -fucose transporter coding sequence was expressed in the Chinese Hamster Ovary (CHO)-gmt5 mutant lacking its endogenous GDP- L -fucose transporter activity. We show that the P. tricornutum transporter is able to rescue the fucosylation of proteins in this CHO-gmt5 mutant cell line, thus demonstrating the functional activity of the diatom transporter and its appropriate Golgi localization. In addition, we overexpressed one of the three FuT candidates, namely the FuT54599, in P. tricornutum and investigated its localization within Golgi stacks of the diatom. Our findings show that overexpression of the FuT54599 leads to a significant increase of the α(1,3)-fucosylation of the diatom endogenous glycoproteins.