Transgenic chicory plants were obtained from different explantsco-cultured with Agrobacterium tumefaciens. Among tap-root,leaf and cotyledonary tissues, etiolated cotyledons showed thegreatest competence for transformation. The Agrobacterium strainsused contained either pGSGLUC1 or pTDE4 as a vector which carryboth the neomycin phosphotransferase II gene (nptll) for kanamycinresistance and ß-glucuronidase gene (uidA) under thecontrol of different promoters. Transformation was confirmedby NPTII enzymatic assay, histochemical analysis of GUS activityand DNA hybridization. Transgenic plants expressed both markergenes in root and shoot tissues. In leaves, GUS activity wasexpressed in all tissue types, whatever the nature of the promoter.Nevertheless, variable heterogeneous patterns of expressionwere observed in the different root tissues. Differential expression of the GUS fusions controlled by thedual TR or the CaMV 35S promoters are discussed. Key words: Chicory, genetic transformation, GUS activity, kanamycin resistance 相似文献
Inbreeding depression, or the reduction in fitness due to mating between close relatives, is a key issue in biology today. Inbreeding negatively affects many fitness‐related traits, including survival and reproductive success. Despite this, very few studies have quantified the effects of inbreeding on vertebrate gamete traits under controlled breeding conditions using a full‐sib mating approach. Here, we provide comprehensive evidence for the negative effect of inbreeding on sperm traits in a bird, the zebra finch Taeniopygia guttata. We compared sperm characteristics of both inbred (pedigree F = 0.25) and outbred (pedigree F = 0) individuals from two captive populations, one domesticated and one recently wild‐derived, raised under standardized conditions. As normal spermatozoa morphology did not differ consistently between inbred and outbred individuals, our study confirms the hypothesis that sperm morphology is not particularly susceptible to inbreeding depression. Inbreeding did, however, lead to significantly lower sperm motility and a substantially higher percentage of abnormal spermatozoa in ejaculate. These results were consistent across both study populations, confirming the generality and reliability of our findings. 相似文献
The interferon-inducible transmembrane (IFITM) family of proteins has been shown to restrict a broad range of viruses in vitro and in vivo by halting progress through the late endosomal pathway. Further, single nucleotide polymorphisms (SNPs) in its sequence have been linked with risk of developing severe influenza virus infections in humans. The number of viruses restricted by this host protein has continued to grow since it was first demonstrated as playing an antiviral role; all of which enter cells via the endosomal pathway. We therefore sought to test the limits of antimicrobial restriction by Ifitm3 using a knockout mouse model. We showed that Ifitm3 does not impact on the restriction or pathogenesis of bacterial (Salmonella typhimurium, Citrobacter rodentium, Mycobacterium tuberculosis) or protozoan (Plasmodium berghei) pathogens, despite in vitro evidence. However, Ifitm3 is capable of restricting respiratory syncytial virus (RSV) in vivo either through directly restricting RSV cell infection, or by exerting a previously uncharacterised function controlling disease pathogenesis. This represents the first demonstration of a virus that enters directly through the plasma membrane, without the need for the endosomal pathway, being restricted by the IFITM family; therefore further defining the role of these antiviral proteins. 相似文献
This study evaluated the effect of application of the semisynthetic triterpenes 3β-acetoxy-norlup-20-one (F4) and 3-chloro-4α,14α-dimethyl-5α-cholest-8-ene (F6) triterpene derivatives from Euphorbia officinarum on the growth of tomato seedlings under normal conditions and when challenged with the pathogens Verticillium dahliae and Agrobacterium tumefaciens. Foliar spray of F4 and F6 significantly improved growth rate, fresh weight, dry weight, and leaf area. In addition, they enhanced several physiological parameters including photosynthetic pigments, proline content, and nitrate reductase activity. Moreover, they induced H2O2 accumulation and increased the activity of several antioxidant enzymes such as catalase, ascorbate peroxidase, and guaiacol peroxidase. They also enhanced disease resistance against V. dahliae and A. tumefaciens. These results suggest that the two semisynthetic triterpenes represent new plant growth regulators and inducers of plant disease resistance.
Whereas remarkable advances have uncovered mechanisms that drive nervous system assembly, the processes responsible for the lifelong maintenance of nervous system architecture remain poorly understood. Subsequent to its establishment during embryogenesis, neuronal architecture is maintained throughout life in the face of the animal’s growth, maturation processes, the addition of new neurons, body movements, and aging. The Caenorhabditis elegans protein SAX-7, homologous to the vertebrate L1 protein family of neural adhesion molecules, is required for maintaining the organization of neuronal ganglia and fascicles after their successful initial embryonic development. To dissect the function of sax-7 in neuronal maintenance, we generated a null allele and sax-7S-isoform-specific alleles. We find that the null sax-7(qv30) is, in some contexts, more severe than previously described mutant alleles and that the loss of sax-7S largely phenocopies the null, consistent with sax-7S being the key isoform in neuronal maintenance. Using a sfGFP::SAX-7S knock-in, we observe sax-7S to be predominantly expressed across the nervous system, from embryogenesis to adulthood. Yet, its role in maintaining neuronal organization is ensured by postdevelopmentally acting SAX-7S, as larval transgenic sax-7S(+) expression alone is sufficient to profoundly rescue the null mutants’ neuronal maintenance defects. Moreover, the majority of the protein SAX-7 appears to be cleaved, and we show that these cleaved SAX-7S fragments together, not individually, can fully support neuronal maintenance. These findings contribute to our understanding of the role of the conserved protein SAX-7/L1CAM in long-term neuronal maintenance and may help decipher processes that go awry in some neurodegenerative conditions. 相似文献
A series of chiral cyclosulfamides have been synthesized in four steps, starting from N-benzoylaminoacids. Regioselective glycosylation of these pseudopyrimidic heterocycles was carried out after deprotection. Best glycosylation results were obtained by preliminary silylation of cyclosulfamides, and their condensation with a tetraacetylribofuranose and pentaacetylglucopyranose is described, which yielded the pseudonucleosides in a beta-anomeric configuration. 相似文献
The response to ATP of peritoneal macrophages from wild-type (WT) and P2X7-invalidated (KO) mice was tested. Low concentrations (1–100 μM) of ATP transiently increased the intracellular concentration
of calcium ([Ca2+]i) in cells from both mice. The inhibition of the polyphosphoinositide-specific phospholipase C with U73122 inhibited this
response especially in WT mice suggesting that the responses coupled to P2Y receptors were potentiated by the expression of
P2X7 receptors. One millimolar ATP provoked a sustained increase in the [Ca2+]i only in WT mice. The response to 10 μM ATP was potentiated and prolonged by ivermectin in both mice. One millimolar ATP increased
the influx of extracellular calcium, decreased the intracellular concentration of potassium ([K+]i) and stimulated the secretion of interleukin-1β (IL-1β) only in cells from WT mice. Ten micromolar ATP in combination with
3 μM ivermectin reproduced these responses both in WT and KO mice. The secretion of IL-1β was also increased by nigericin
in WT mice and the secretory effect of a combination of ivermectin with ATP in KO mice was suppressed in a medium containing
a high concentration of potassium. In WT mice, 150 μM BzATP stimulated the uptake of YOPRO-1. Incubation of macrophages from
WT and KO mice with 10 μM ATP resulted in a small increase of YOPRO-1 uptake, which was potentiated by addition of 3 μM ivermectin.
The uptake of this dye was unaffected by pannexin-1 blockers. In conclusion, prolonged stimulation of P2X4 receptors by a combination of low concentrations of ATP plus ivermectin produced a sustained activation of the non-selective
cation channel coupled to this receptor. The ensuing variations of the [K+]i triggered the secretion of IL-1β. Pore formation was also triggered by activation of P2X4 receptors. Higher concentrations of ATP elicited similar responses after binding to P2X7 receptors. The expression of the P2X7 receptors was also coupled to a better response to P2Y receptors. 相似文献