Dendritic cells infiltrating human non-small cell lung cancer are blocked at immature stage

The efficacy of immune response to control human cancer remains controversial. It is particularly debated whether and to what extent the capacity of tumor-infiltrating dendritic cells (DC) to drive immunization can be turned off by transformed cells, leading to tumor-specific tolerance rather than immunization. To address this issue, we have characterized the DC isolated from human non-small cell lung cancer (NSCLC). These biopsy specimens contained CD11c(high) myeloid DC (mDC), but also CD11c(-) plasmacytoid DC (pDC) and a third DC subset expressing intermediate level of CD11c. Compared with peripheral blood, CD11c(high) tumor-infiltrating DC (TIDC) displayed a "semi-mature" phenotype, and TLR4 or TLR8 stimulation drove them to mature partially and to secrete limited amounts of cytokines. In contrast, most tumor-infiltrating pDC were immature but underwent partial maturation after TLR7 activation, whereas TLR9 ligation triggered low secretion of IFN-alpha. CD11c(int) mDC represented approximately 25% of total DC in tumoral and peritumoral tissues and expressed low levels of costimulatory molecules contrasting with high levels of the immunoinhibitory molecule B7-H1. Finally, the poor APC function of total TIDC even after TLR stimulation and the migratory response of both tumor-infiltrating mDC and pDC toward CCL21 and SDF-1 in vitro suggested their ability to compromise the tumor-specific immune response in draining lymph nodes in vivo. Further studies will be required to establish the specific role of the three TIDC subsets in tumor immunity and to draw conclusions for the design of therapeutic strategies.     

Sensitive gene expression profiling of human T cell subsets reveals parallel post-thymic differentiation for CD4+ and CD8+ lineages

The differentiation of CD4(+) or CD8(+) T cells following priming of naive cells is central in the establishment of the immune response against pathogens or tumors. However, our understanding of this complex process and the significance of the multiple subsets of differentiation remains controversial. Gene expression profiling has opened new directions of investigation in immunobiology. Nonetheless, the need for substantial amount of biological material often limits its application range. In this study, we have developed procedures to perform microarray analysis on amplified cDNA from low numbers of cells, including primary T lymphocytes, and applied this technology to the study of CD4 and CD8 lineage differentiation. Gene expression profiling was performed on samples of 1000 cells from 10 different subpopulations, defining the major stages of post-thymic CD4(+) or CD8(+) T cell differentiation. Surprisingly, our data revealed that while CD4(+) and CD8(+) T cell gene expression programs diverge at early stages of differentiation, they become increasingly similar as cells reach a late differentiation stage. This suggests that functional heterogeneity between Ag experienced CD4(+) and CD8(+) T cells is more likely to be located early during post-thymic differentiation, and that late stages of differentiation may represent a common end in the development of T-lymphocytes.     

Zonation des brachiopodes du Jurassique moyen sur la marge sud de la Téthys occidentale (Maroc, Algérie occidentale): Comparaison avec la marge nord-téthysienne française

A new and yet unpublished palaeontological revision of very important collections accomplished these last thirty years in many localities of Morocco and Western Algeria joined to the already published data, allow us to propose a biostratigraphical succession of the Middle Jurassic Brachiopods suitable to the Southern Margin of the Western Tethys. This Brachiopod scale is correlated with the standard chronostratigraphy based on ammonites. It involves eight zones and six sub-zones separated by five interval zones where Brachiopods are missing. Moreover, brachiopods have not been discovered in Early Aalenian and Late Callovian. Afterwards, the two brachiopod zonations established on the northern and southern margins of the Western Tethys are compared. On a paleontological plane, a new definition of the species Burmirhynchiaathiensis warrants to precise its vertical distribution (Parkinsoni and Zigzag zones) and to give a better distinction with Burmirhynchiatermierae (Humphriesianum and Niortense zones).     

Physical association between neuropeptide FF and micro-opioid receptors as a possible molecular basis for anti-opioid activity

Neuropeptide FF (NPFF) modulates the opioid system by exerting functional anti-opioid activity on neurons, the mechanism of which is unknown. By using a model of SH-SY5Y cells, we recently postulated that anti-opioid activity likely takes place upstream from the signaling cascade, suggesting that NPFF receptors could block opioid receptors by physical interaction. In the present study, fluorescence techniques were used to monitor the physical association and the dynamic of NPFF2 and micro-opioid (MOP) receptors tagged with variants of the green fluorescent protein. Importantly, cyan fluorescent protein-tagged NPFF2 receptors retained their capacity to antagonize opioid receptors. Fluorescence resonance energy transfer (FRET) and coimmunoprecipitation studies indicate that NPFF and MOP receptors are close enough to generate a basal FRET signal. The opioid agonist Tyr-D-Ala-Gly-NMe-Phe-Gly-ol disrupts by 20-30% this FRET signal, mainly because it concomitantly induces 40% internalization of receptors. In contrast, the NPFF analog 1DMe significantly increases by 10-15% the basal FRET signal, suggesting an association between both receptors. In addition, 1DMe reduces, by half, MOP receptor internalization, indicating that, besides a functional blockade of opioid receptors, the NPFF analog also inhibits their internalization. Finally, as a first report showing the modulation of the mobility of a G-protein-coupled receptor by another one, fluorescence recovery after photobleaching analysis reveals that 1DMe modifies the lateral diffusion of MOP receptors in the cell membrane, changing them from a confined to a freely diffusing state. By promoting NPFF-MOP receptor heteromerization, 1DMe could disrupt the domain organization of MOP receptors in the membrane, resulting in a reduction of opioid response.     

Gene expression and biochemical analysis of cheese-ripening yeasts: focus on catabolism of L-methionine, lactate, and lactose

DNA microarrays of 86 genes from the yeasts Debaryomyces hansenii, Kluyveromyces marxianus, and Yarrowia lipolytica were developed to determine which genes were expressed in a medium mimicking a cheese-ripening environment. These genes were selected for potential involvement in lactose/lactate catabolism and the biosynthesis of sulfur-flavored compounds. Hybridization conditions to follow specifically the expression of homologous genes belonging to different species were set up. The microarray was first validated on pure cultures of each yeast; no interspecies cross-hybridization was observed. Expression patterns of targeted genes were studied in pure cultures of each yeast, as well as in coculture, and compared to biochemical data. As expected, a high expression of the LAC genes of K. marxianus was observed. This is a yeast that efficiently degrades lactose. Several lactate dehydrogenase-encoding genes were also expressed essentially in D. hansenii and K. marxianus, which are two efficient deacidifying yeasts in cheese ripening. A set of genes possibly involved in l-methionine catabolism was also used on the array. Y. lipolytica, which efficiently assimilates l-methionine, also exhibited a high expression of the Saccharomyces cerevisiae orthologs BAT2 and ARO8, which are involved in the l-methionine degradation pathway. Our data provide the first evidence that the use of a multispecies microarray could be a powerful tool to investigate targeted metabolism and possible metabolic interactions between species within microbial cocultures.     

The Effect of Temperature Stress on Development and Heat-shock Protein Expression in Larval Green Sturgeon (Acipenser mirostris)

Water temperature is an important environmental variable influencing the distribution and health of coldwater fishes such as the green sturgeon, Acipenser medirostris. In this study, we investigated if larval sturgeon were able to tolerate or recover from acute, non-lethal temperature stress that commonly causes deformed notochords, and sought to identify the role of heat-shock proteins (hsp) in stress tolerance. The hsp response is one of the most important cellular mechanisms to prevent the damaging effects of thermal cellular stress, and differences in the ability to over-express hsps during stressful conditions may be associated with an organism’s vulnerability and the extent of thermal injury. In this study, newly hatched larvae were maintained at 17°C (control), or exposed to (a) 26°C for 3 d then maintained at 17°C until yolk-sac absorption or (b) 26°C until yolk-sac absorption. Individuals with deformed notochords were counted, and hsp60, 72, 78 and 89 were analyzed in both normal and deformed larvae by western blotting. Approximately 33% of fish developed curved notochords within the first 3 d of exposure to 26°C. After transfer to cool water 16.5% showed deformities at stage 45, suggesting a significant number of larvae had recovered. Hsp levels remained elevated for at least 9 days after termination of heat-exposure. Overall, percentage of deformed larvae, and hsp72/hsp78 levels were highest in fish continuously exposed to 26°C until yolk-sac absorption. Deformed individuals had significantly higher expression levels of hsp72 and hsp78, and lower hsp60 levels than normal larvae. We conclude that expression of hsp72 and hsp78 and potentially hsp60 are linked to phenotypic variation in the response and vulnerability of green sturgeon larvae to thermal stress.     

North American Green and European Atlantic Sturgeon: Comparisons of Life Histories and Human Impacts

Green and European Atlantic sturgeon are listed as a vulnerable and a critically endangered species, respectively. These anadromous species inhabit different continents but have many similar life history traits and demographic characteristics, including wide geographic ranges, similar migratory and foraging behavior, age and size structures of reproductive stocks and, historically, diverse population structures. The differences are limited to tetraploid genome and much larger egg size and lower fecundity in green sturgeon, reflecting the adaptations to different geomorphology and biota of the Pacific region. Both species have been affected by over-harvest and habitat losses but the severity of these impacts have been greater and lasted longer for the European Atlantic sturgeon, resulting in loss of diversity and extirpation of all but one stock. From the comparison of human impact on two species we conclude that preventive actions should be taken at the early warning signs of changes in population and recruitment. These should mitigate multiple factors of human activity affecting sturgeon stocks and their habitats.     

Energy expenditure and wing beat frequency in relation to body mass in free flying Barn Swallows (<Emphasis Type="Italic">Hirundo rustica</Emphasis>)

Many bird species steeply increase their body mass prior to migration. These fuel stores are necessary for long flights and to overcome ecological barriers. The elevated body mass is generally thought to cause higher flight costs. The relationship between mass and costs has been investigated mostly by interspecific comparison and by aerodynamic modelling. Here, we directly measured the energy expenditure of Barn Swallows (Hirundo rustica) flying unrestrained and repeatedly for several hours in a wind tunnel with natural variations in body mass. Energy expenditure during flight (e _f, in W) was found to increase with body mass (m, in g) following the equation e _f = 0.38 × m ^0.58. The scaling exponent (0.58) is smaller than assumed in aerodynamic calculations and than observed in most interspecific allometric comparisons. Wing beat frequency (WBF, in Hz) also scales with body mass (WBF = 2.4 × m ^0.38), but at a smaller exponent. Hence there is no linear relationship between e _f and WBF. We propose that spontaneous changes in body mass during endurance flights are accompanied by physiological changes (such as enhanced oxygen and nutrient supply of the muscles) that are not taken into consideration in standard aerodynamic calculations, and also do not appear in interspecific comparison.