Germination and phenology of 1-year-old maritime pine (Pinus pinaster Aït.) seedlings under continuous light

Summary Nine half-sib families of maritime pine (Pinus pinaster Aït.), of known vigor and growth pattern (monocyclic vs polycyclic), were grown under continuous light in two temperature regimes. Results of germination and development to the beginning of the second flush are reported here. Families significantly differed for mean date of germination and date of first budset. After 18 weeks of continuous light most of the seedlings had set a bud. High temperature (25° C vs 25° C/20°C) hastened first budset by approximately 5 days. However, 3 families had not reached 75% budset at the end of the experiment. Variation in date of first budset was almost exclusively explained by variation in the period between initiation of primary needles and budset. Further, 2 developmental stages could be distinguished within this period, the boundary between them being the emergence of the first secondary needles. Variation in height at first budset was mostly due to variation in growth rate, not in duration. Possible causes of early budset and implication for selection are discussed.     

Biological effects of glucocorticoid hormones on two rat colon adenocarcinoma cell lines

Glucocorticoid hormones are thought to play a role in carcinogenesis as they regulate cell differentiation and proliferation. We have investigated the effect of dexamethasone on two cell lines derived from a colon carcinoma, which differ by their tumorigenicity. Dexamethasone was found to inhibit growth of both the progressive (PROb) and the regressive clone (REGb). Upon glucocorticoid treatment, PROb cells were found to secrete an additional M_r 40,000 protein. The synthesis and the release in the culture medium of this protein is stimulated specifically by glucocorticoid agonists, and not by other steroid hormones. The anti-glucocorticoid RU 38486 is ineffecient and suppresses the induction of this protein by dexamethasone. Induction is sensitive to actinomycin D, suggesting that regulation may be related to an alteration of the rate of mRNA synthesis. The cellular effect of glucocorticoid hormones being mediated through a specific soluble receptor, we have characterized this protein. The PROb cells contained more specific glucocorticoid-binding sites ( 170,000 sites per cell) than the regressive ones (REGb cells; 100,000 sites per cell). In both clones, the receptor was associated with the M_r 90,000 heat shock protein to yield large complexes (Stokes radius R_s 7.5 nm), which were dissociated to the same extent upon heat- and salt-treatment. The steroid- and DNA-binding unit of the receptor, characterized under denaturing conditions using an anti-receptor monoclonal antibody, was found to be more degraded in the PROb cell line.     

Identification, cloning, and characterization of rcsF, a new regulator gene for exopolysaccharide synthesis that suppresses the division mutation ftsZ84 in Escherichia coli K-12.

A new gene, designated rcsF, was located adjacent to drpA at the 5.2-min position of the genetic map of Escherichia coli. The deduced amino acid sequence encoded by the rcsF gene indicates a small protein of 133 amino acid residues with a calculated pI of 10.8 that is rich in proline, serine, alanine, and cysteine residues. When overexpressed as a result of its presence on a multicopy plasmid, rcsF confers a mucoid phenotype and restores colony formation to ftsZ84 mutant cells on L agar medium containing no added NaCl. These two phenotypes are not observed in rcsB mutant cells. Ion mutant cells harboring an rcsF mutation accumulate considerably lower levels of exopolysaccharides, whereas the presence of a multicopy rcsF plasmid not only increases capsule synthesis but also confers a mucoid phenotype at 37 degrees C, a temperature at which ion mutant cells are known not to form mucoid colonies. RcsF does not stimulate the expression of rcsB, indicating that it exerts its action through the RcsB protein, possibly by phosphorylation. It is also shown that RcsF stimulation of capsule synthesis is RcsA-dependent, whereas colony formation of ftsZ84 mutant cells can be restored by RcsF in the absence of RcsA.     

Vascular control of the pig nasal mucosa: distribution and effect of somatostatin in relation to noradrenaline and neuropeptide Y

By means of immunohistochemistry and radioimmunoassay (RIA), we have investigated the possible occurrence of somatostatin (SOM)-like immunoreactivity (-LI) in the autonomic innervation of the pig nasal mucosa. SOM-immunoreactive (-IR) fibres were present around nasal arteries, arterioles and venous sinusoids. Double-labelling experiments revealed that SOM-LI was co-localized with the noradrenaline (NA) markers tyrosine hydroxylase and dopamine-β-hydroxylase as well as with neuropeptide Y (NPY) in a subpopulation of neurons in the superior cervical sympathetic ganglion and in perivascular nerve terminals. Furthermore, SOM-LI was also present in perivascular fibres containing vasoactive intestinal polypeptide (VIP) and NPY of presumably parasympathetic origin. The parasympathetic fibres that were associated with glands contained peptide histidine isoleucine (PHI), VIP and NPY but not SOM, suggesting that in the nasal mucosa SOM-IR is restricted to perivascular nerves. As revealed by RIA, the content of SOM-LI in biopsies of both nasal mucosa and superior cervical sympathetic ganglion was about 12 pmol/g and the reverse phase HPLC characterisation of SOM-LI shown two separate peaks for SOM-28 and SOM-14.     

Characterization of bradykinin receptors in peripheral organs.

Bradykinin (BK) and related kinins are potent stimulants of the rabbit jugular vein, the hamster urinary bladder, and the guinea pig trachea. The characterization of kinin receptors in these tissues was made with agonists and antagonists. Results obtained with agonists indicate that bradykinin and kallidin are much more active than des-Arg9-BK and suggest the presence of B2 receptors in the three organs. Some new agonists were also tested and the BK analogue, [Hyp3,Tyr(Me)8]BK, was found to be a potent and selective stimulant of the three preparations, with pD2 values of 8.56, 8.00, and 8.39, respectively, but inactive on the rabbit aorta (a B1-receptor system). Contractile effects of kinins in the rabbit jugular vein and hamster urinary bladder were reduced or eliminated by B2-receptor antagonists but at different concentration levels; e.g., acetyl-D-Arg[Hyp3,D-Phe7]BK showed pA2 values of 7.78 on the rabbit jugular vein but only 5.72 on hamster urinary bladder. This compound contracted the guinea-pig trachea and was found to be inactive as an antagonist on this preparation. Contractions of the hamster urinary bladder and the guinea-pig trachea in response to bradykinin were markedly reduced or eliminated by indomethacin and by BW 755C, while those of the rabbit jugular vein were not modified. The present findings indicate that the myotropic effect of kinins on the rabbit jugular vein depends on the activation of B2 receptors and suggest that B2 receptors are largely responsible also for the response of the hamster urinary bladder. B2 receptors and (or) a nonreceptor mechanism appear to be involved in the stimulant effects of the kinin agonists and some antagonists in the guinea-pig trachea.     

In vivo modulation of atypical mycobacterial infection: adjuvant therapy increases resistance to Mycobacterium avium by enhancing macrophage effector functions

Susceptible BALB/c mice were infected iv with a strain of Mycobacterium avium and infused with different biological response modifiers (BRM) in a gel delivery system so as to modify the progression of the infection in a beneficial fashion. Infusion of IL-2 or IL-4 in hydrophobic gels led to no significant enhancement of resistance. Infusion of muramyl dipeptide in hypromellose led to a significant enhancement of resistance against the M. avium, as seen by a significant reduction of colony-forming units (CFU) in the spleens of infected mice. Similarly, infusion of interleukin-1 beta in hypromellose in infected mice led to a significant reduction in CFU counts in the organs of mice. The mechanism(s) responsible for this enhanced resistance was studied further. It was found that infected mice developed profound immunosuppression, as judged by mitogenic and antigenic stimulation. Mice infused with MDP/hypromellose developed a similar immuno-suppression, suggesting that this adjuvant immunotherapy did not act by stimulating a T-cell response or by abrogating a putative suppressive phenomenon. Macrophages from mice infused with MDP alone were no more bacteriostatic for a virulent M. avium than control cells. However, macrophages from infected mice infused with MDP/hypromellose were more bacteriostatic for M. avium than cells from mice infected with M. avium and infused with the hydrophobic gel only. Overall, these results suggest that adjuvant immunotherapy is beneficial in M. avium infections.     

Intraspecific variability of the phenology and morphology of three protected dragonflies between natural and artificial habitats

Changes in phenology and in body size are two of the three main consequences of global warming on organisms. We investigated whether living in a warm artificial habitat would induce changes in the phenology and body size of dragonflies. We monitored in natura the emergence pattern of three protected and red-listed dragonfly species in three geographically close systems which differ in thermal profiles: a medium-sized river, one of its tributaries and an artificial lake fed by the water of the tributary. We also investigated the morphological variability of one of the species between the three systems. We showed an asynchrony of emergence for the three species, as well as morphological variability between the lake and the two rivers. Individuals from the lake emerged earlier and were smaller than those from the two rivers. These results are in agreement with a temperature-induced response hypothesis as the lake is warmer than the two rivers. Asynchrony of emergence between neighbouring populations triggers questions related to metapopulation functioning and about the fitness and the fate of the early-emerging individuals. Understanding the response of these species to local thermal conditions will help to improve population monitoring and conservation.     

In‐line monitoring of amino acids in mammalian cell cultures using raman spectroscopy and multivariate chemometrics models

The application of PAT for in‐line monitoring of biopharmaceutical manufacturing operations has a central role in developing more robust and consistent processes. Various spectroscopic techniques have been applied for collecting real‐time data from cell culture processes. Among these, Raman spectroscopy has been shown to have advantages over other spectroscopic techniques, especially in aqueous culture solutions. Measurements of several process parameters such as glucose, lactate, glutamine, glutamate, ammonium, osmolality and VCD using Raman‐based chemometrics models have been reported in literature. The application of Raman spectroscopy, coupled with calibration models for amino acid measurement in cell cultures, has been assessed. The developed models cover four amino acids important for cell growth and production: tyrosine, tryptophan, phenylalanine and methionine. The chemometrics models based on Raman spectroscopy data demonstrate the significant potential for the quantification of tyrosine, tryptophan and phenylalanine. The model for methionine would have to be further refined to improve quantification.     

Genetic mapping of quantitative trait loci for tuber-cadmium and zinc concentration in potato reveals associations with maturity and both overlapping and independent components of genetic control

Key message

Cd is a toxic metal, whilst Zn is an essential for plant and human health. Both can accumulate in potato tubers. We examine the genetic control of this process.

Abstract

The aim of this study was to map quantitative trait loci (QTLs) influencing tuber concentrations of cadmium (Cd) and zinc (Zn). We developed a segregating population comprising 188 F₁ progeny derived from crossing two tetraploid cultivars exhibiting divergent tuber-Cd-accumulation phenotypes. These progeny were genotyped using the SolCap 8303 SNP array, and evaluated for Cd, Zn, and maturity-related traits. Linkage and QTL mapping were performed using TetraploidSNPMap software, which incorporates all allele dosage information. The final genetic map comprised 3755 SNP markers with average marker density of 2.94 per cM. Tuber-Cd and Zn concentrations were measured in the segregating population over 2 years. QTL mapping identified four loci for tuber-Cd concentration on chromosomes 3, 5, 6, and 7, which explained genetic variance ranging from 5 to 33%, and five loci for tuber-Zn concentration on chromosome 1, 3, 5, and, 6 explaining from 5 to 38% of genetic variance. Among the QTL identified for tuber-Cd concentration, three loci coincided with tuber-Zn concentration. The largest effect QTL for both tuber-Cd and Zn concentration coincided with the maturity locus on chromosome 5 where earliness was associated with increased tuber concentration of both metals. Coincident minor-effect QTL for Cd and Zn sharing the same direction of effect was also found on chromosomes 3 and 6, and these were unrelated to maturity The results indicate partially overlapping genetic control of tuber-Cd and Zn concentration in the cross, involving both maturity-related and non-maturity-related mechanisms.