Calcitonin gene-related peptide inhibits interleukin 2 production by murine T lymphocytes.

Evidence from the literature suggests that the nervous and the immune systems closely interact via neuromediators, which affect the immune system, and cytokines, which control nerve cell growth and activity. Calcitonin gene-related peptide (CGRP) is a neuropeptide that has been identified in numerous tissues including immune organs and inhibits the proliferation of spleen cells. We investigated whether CGRP altered the function of T lymphocytes. We present evidence that CGRP induces a dose-dependent cAMP accumulation in interleukin 2-producing TH1 cells and inhibits their production of interleukin 2. These effects are prevented by CGRP8-37, a CGRP antagonist that is missing the first 7 amino acids. This CGRP-mediated inhibition of interleukin 2 production is accompanied by a decrease in interleukin 2 mRNA accumulation. CGRP also inhibits the accumulation of mRNA coding for tumor necrosis factor-alpha and -beta and interferon-gamma. Thus, we have identified one mechanism by which CGRP inhibits the proliferation of spleen cells.     

Phenomics allows identification of genomic regions affecting maize stomatal conductance with conditional effects of water deficit and evaporative demand

Stomatal conductance is central for the trades‐off between hydraulics and photosynthesis. We aimed at deciphering its genetic control and that of its responses to evaporative demand and water deficit, a nearly impossible task with gas exchanges measurements. Whole‐plant stomatal conductance was estimated via inversion of the Penman–Monteith equation from data of transpiration and plant architecture collected in a phenotyping platform. We have analysed jointly 4 experiments with contrasting environmental conditions imposed to a panel of 254 maize hybrids. Estimated whole‐plant stomatal conductance closely correlated with gas‐exchange measurements and biomass accumulation rate. Sixteen robust quantitative trait loci (QTLs) were identified by genome wide association studies and co‐located with QTLs of transpiration and biomass. Light, vapour pressure deficit, or soil water potential largely accounted for the differences in allelic effects between experiments, thereby providing strong hypotheses for mechanisms of stomatal control and a way to select relevant candidate genes among the 1–19 genes harboured by QTLs. The combination of allelic effects, as affected by environmental conditions, accounted for the variability of stomatal conductance across a range of hybrids and environmental conditions. This approach may therefore contribute to genetic analysis and prediction of stomatal control in diverse environments.     

Preliminary investigations on somatic embryogenesis from leaf discs of red oak (Quercus rubra L.)

Somatic embryos were obtained from leaf discs of juvenile red oak plants. Basal inductive nutrient medium was a modified Murashige and Skoog solution enriched with 500 mg L^–1 casein hydrolysate, 100 mg L^–1 polyvinylpyrrolidone, 5.4 M naphthaleneacetic acid and 0.09 M benzyladenine. Embryogenesis was obtained only from leaf discs in the presence of light and increased when the adaxial surface of the explants (with midrib or main veins present) was in contact with the medium. Large variation was observed in all experiments. Recurrent embryogenesis was observed at the base of embryo clusters with callus present; conversely, embryogenic potential was rapidly lost by subculturing full calli. Maturation, germination and development of isolated somatic embryos were obtained. However, the vast majority of embryos did not have viable apical bud meristems and on only a few occasions were shoots produced.Abbreviations BA N⁶-benzyladenine - CH casein hydrolysate - 2iP isopentenyladenine - NAA naphthaleneacetic acid - 2.4-D 2.4-dichlorophenoxyacetic acid - GA gibberellic acid - PVP polyvinylpyrrolidone     

A mutant of Azospirillum brasilense Sp7 impaired in flocculation with a modified colonization pattern and superior nitrogen fixation in association with wheat.

We report here significant phenotypic and genetic differences between Azospirillum brasilense Sp7 and spontaneous mutant Sp7-S and their related properties in association with wheat. In contrast to the wild-type strain of Sp7, colonies of Sp7-S stained weakly with Congo red when grown on agar media containing the dye and did not flocculate in the presence of fructose and nitrate. Scanning and transmission electron micrographs showed clearly that the Sp7-S strain lacked surface materials present as a thick layer on the surface of the wild-type Sp7 strain. Different patterns of colonization on wheat roots between Sp7 and Sp7-S, revealed by in situ studies using nifA-lacZ as a reporter gene, were related to a large increase in nitrogenase activity (acetylene reduction) with Sp7-S in association with normal and 2,4-dichlorophenoxyacetic acid-treated wheat for assays conducted under conditions in which the nitrogenase activity of free-living Azospirillum organisms was inhibited by an excess of oxygen. Randomly amplified polymorphic DNA analysis indicated the close genetic relationship of Sp7-S to several other sources of Sp7, by comparison to other recognized strains of A. brasilense. Genetic complementation of Sp7-S was achieved with a 9.4-kb fragment of DNA cloned from wild-type Sp7, restoring Congo red staining and flocculation.     

Imbalanced distribution of Plasmodium falciparum MSP-1 genotypes related to sickle-cell trait.

BACKGROUND: The sickle-cell trait protects against severe Plasmodium falciparum malaria and reduces susceptibility to mild malaria but does not prevent infection. The exact mechanism of this protection remains unclear. We have hypothesized that AS individuals are protected by virtue of being less susceptible to a subset of parasite strains; thus we compared some genetic characteristics of parasites infecting AS and AA subjects. MATERIALS AND METHODS: Blood was collected from asymptomatic individuals living in two different regions of Africa. The polymorphic MSP-1 and MSP-2 loci were genotyped using a PCR-based methodology. Individual alleles were identified by size polymorphism, amplification using family-specific primers, and hybridization using family-specific probes. Multivariate logistic regression was used to analyze allele distribution. RESULTS: In Senegalese carriers, age and hemoglobin type influenced differently the distribution of the three MSP-1 families and had an impact on distinct individual alleles, whereas the distribution of MSP-2 alleles was marginally affected. There was no influence of other genetic traits, including the HLA Bw53 genotype, or factors such as place of residence within the village. In a cohort of Gabonese schoolchildren in which the influence of age was abrogated, a similar imbalance in the MSP-1 allelic distribution but not of MSP-2 allelic distribution by hemoglobin type was observed. CONCLUSIONS: The influence of the host's hemoglobin type on P. falciparum genotypes suggests that parasite fitness for a specific host is strain-dependent, which is consistent with our hypothesis that innate resistance might result from reduced fitness of some parasite strains for individuals with sickle-cell traits.     

Increase in benthic trophic reliance on methane in 14 French lakes during the Anthropocene

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Effect of nicotine on in vivo secretion of melanocorticotropic hormones in the rat

Corticosterone, ACTH, β-endorphin and α-MSH were measured in rat plasma by radioimmunoassay before and 2,5,15,30 minutes after an intraperitoneal injection of nicotine (500 μg/Kg b.w.). Nicotine induced an increase of plasma corticosterone (p < 0.05 at t + 15 min), ACTH and β-endorphin (p < 0.01 at t + 5 min) and a decrease of α-MSH (p < 0.005 at t + 15 min). Dose response experiments showed an increase of corticosterone, ACTH, β-endorphin 15 min after 250 μg/Kg b.w. nicotine I.P., no effect being observed after injection of 100 μg/Kg b.w. The decrease of α-MSH was observed 15 min after 100, 250 or 500 μg/Kg b.w. nicotine I.P. Our results suggest that the increase of corticosterone is mediated through ACTH release.     

Cellulose Fermentation by an Asporogenous Mutant and an Ethanol-Tolerant Mutant of Clostridium thermocellum

Two mutants of Clostridium thermocellum were isolated after UV light mutagenesis. Mutant A1, selected as asporogenous, exhibited a fermentation pattern similar to that of the wild type. However, at pH 6.5, the mutant degraded 12% more cellulose than did the wild type, leading to enhanced ethanol production. Mutant 647, selected as ethanol tolerant, was able to grow in medium containing 4% ethanol. During the early stage of the exponential growth phase, ethanol was produced as the main product, up to a concentration of about 9 g/liter. After 3 days of culture, 48.3 g (89% of the initial amount) of degraded cellulose per liter was fermented into 12.7 g of ethanol per liter.     

Ethanol production by Clostridium thermocellum grown on hydrothermally and organosolv-pretreated lignocellulosic materials

Summary Two strains of the thermophilic anaerobe Clostridium thermocellum, the wild type NCIB 10682 and its ethanol-hyperproductive mutant 647, were tested for their ability to grow on natural lignocellulosic materials (poplar wood, wheat straw) which had been pretreated by either hydrothermolysis or an organosolv process. For both materials and both strains, the dependencies of substrate accessibility on the pretreatment temperature were established in terms of cellulose hydrolysis and of product formation.In addition to the non-pH-controlled shake flask assays, in vitro experiments with cell-free culture supernatant and in vivo cellulolyses under pH regulation in a laboratory fermenter indicated that lignocellulosics pretreated at approx. 230°C were degraded efficiently by the Clostridium strains investigated.     

Over a Century of Neuron Culture: From the Hanging Drop to Microfluidic Devices

The brain is the most intricate, energetically active, and plastic organ in the body. These features extend to its cellular elements, the neurons and glia. Understanding neurons, or nerve cells, at the cellular and molecular levels is the cornerstone of modern neuroscience. The complexities of neuron structure and function require unusual methods of culture to determine how aberrations in or between cells give rise to brain dysfunction and disease. Here we review the methods that have emerged over the past century for culturing neurons in vitro, from the landmark finding by Harrison (1910) — that neurons can be cultured outside the body — to studies utilizing culture vessels, micro-islands, Campenot and brain slice chambers, and microfluidic technologies. We conclude with future prospects for neuronal culture and considerations for advancement. We anticipate that continued innovation in culture methods will enhance design capabilities for temporal control of media and reagents (chemotemporal control) within sub-cellular environments of three-dimensional fluidic spaces (microfluidic devices) and materials (e.g., hydrogels). They will enable new insights into the complexities of neuronal development and pathology.