RESUMO
Lycopodium alkaloids (LAs) are derived from lysine (Lys) and are found mainly in Huperziaceae and Lycopodiaceae. LAs are potentially useful against Alzheimer's disease, schizophrenia, and myasthenia gravis. Here, we cloned the bifunctional lysine/ornithine decarboxylase (L/ODC), the first gene involved in LA biosynthesis, from the LA-producing plants Lycopodium clavatum and Huperzia serrata We describe the in vitro and in vivo functional characterization of the L. clavatum L/ODC (LcL/ODC). The recombinant LcL/ODC preferentially catalyzed the decarboxylation of l-Lys over l-ornithine (l-Orn) by about 5 times. Transient expression of LcL/ODC fused with the amino or carboxyl terminus of green fluorescent protein, in onion (Allium cepa) epidermal cells and Nicotiana benthamiana leaves, showed LcL/ODC localization in the cytosol. Transgenic tobacco (Nicotiana tabacum) hairy roots and Arabidopsis (Arabidopsis thaliana) plants expressing LcL/ODC enhanced the production of a Lys-derived alkaloid, anabasine, and cadaverine, respectively, thus, confirming the function of LcL/ODC in plants. In addition, we present an example of the convergent evolution of plant Lys decarboxylase that resulted in the production of Lys-derived alkaloids in Leguminosae (legumes) and Lycopodiaceae (clubmosses). This convergent evolution event probably occurred via the promiscuous functions of the ancestral Orn decarboxylase, which is an enzyme involved in the primary metabolism of polyamine. The positive selection sites were detected by statistical analyses using phylogenetic trees and were confirmed by site-directed mutagenesis, suggesting the importance of those sites in granting the promiscuous function to Lys decarboxylase while retaining the ancestral Orn decarboxylase function. This study contributes to a better understanding of LA biosynthesis and the molecular evolution of plant Lys decarboxylase.
Assuntos
Alcaloides/metabolismo , Carboxiliases/metabolismo , Evolução Molecular , Huperzia/enzimologia , Lycopodium/enzimologia , Ornitina Descarboxilase/metabolismo , Alcaloides/química , Arabidopsis/genética , Arabidopsis/metabolismo , Vias Biossintéticas , Carboxiliases/genética , Descarboxilação , Huperzia/química , Huperzia/genética , Lycopodium/química , Lycopodium/genética , Lisina/metabolismo , Mutagênese Sítio-Dirigida , Cebolas/genética , Cebolas/metabolismo , Ornitina Descarboxilase/genética , Filogenia , Folhas de Planta/química , Folhas de Planta/enzimologia , Folhas de Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/química , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Proteínas Recombinantes , Nicotiana/genética , Nicotiana/metabolismoRESUMO
Gliotoxin is an important virulence factor of Aspergillus fumigatus. Although GliA putatively belongs to the major facilitator superfamily in the gliotoxin biosynthesis cluster, its roles remain unclear. To determine the function of GliA, we disrupted gliA in A. fumigatus. gliA disruption increased the susceptibility of A. fumigatus to gliotoxin. The gliT and gliA double-disrupted mutant had even higher susceptibility to gliotoxin than each individual disruptant. The extracellular release of gliotoxin was greatly decreased in the gliA disruptant. Mice infected with the gliA disruptant of A. fumigatus showed higher survival rates than those infected with the parent strain. These results strongly indicate that GliA, in addition to GliT, plays a significant role in the tolerance to gliotoxin and protection from extracellular gliotoxin in A. fumigatus by exporting the toxin. This also allows the fungus to evade the harmful effect of its own gliotoxin production. Moreover, GliA contributes to the virulence of A. fumigatus through gliotoxin secretion.
Assuntos
Aspergilose/microbiologia , Aspergillus fumigatus/genética , Proteínas Fúngicas/metabolismo , Gliotoxina/metabolismo , Sequência de Aminoácidos , Animais , Aspergillus fumigatus/efeitos dos fármacos , Aspergillus fumigatus/patogenicidade , Aspergillus fumigatus/fisiologia , Linhagem Celular , Proteínas Fúngicas/genética , Deleção de Genes , Humanos , Hospedeiro Imunocomprometido , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Família Multigênica , Mutação , Oxirredutases/genética , Oxirredutases/metabolismo , Alinhamento de Sequência , Virulência , Fatores de VirulênciaRESUMO
Background: Hypnotics are frequently used for insomnia in pregnant and lactating women. This case study assessed zolpidem concentrations in the cord blood and breast milk and ramelteon concentrations in the breast milk of a woman who was treated with zolpidem and ramelteon for insomnia. Materials and Methods: Zolpidem concentrations were measured in maternal serum, breast milk, and cord blood. Concentrations of ramelteon and M-II, an active ramelteon metabolite, were measured in maternal serum and breast milk. Case Report: A 46-year-old female patient diagnosed with insomnia received 5-10 mg/day zolpidem during pregnancy and lactation and 8 mg/day ramelteon during lactation. A male infant weighing 3,329 g was born at 38 weeks' gestation, with no congenital abnormalities found during pregnancy or at birth. The infant was normal at the 1-month postpartum checkup. The maternal/placental ratio of zolpidem concentrations was 0.1 at 7.4 hours after maternal dosing, similar to that reported in previous studies. The calculated relative infant dose through breast milk based on the maximum drug concentration in breast milk at 2.2 hours after maternal dosing was 2.7% for zolpidem and 0.2% for ramelteon. Ramelteon and its metabolite (M-II) concentrations in the breast milk were equivalent to those in the maternal serum, although the infant exposure of these drugs was low for an oral dose. Conclusions: In the current case, zolpidem transferred into the placenta and breast milk, and ramelteon transferred into the breast milk. Further studies should assess the safety of zolpidem and ramelteon in fetus and breastfed infants.