In vitro characterization of the NAD+ synthetase NadE1 from Herbaspirillum seropedicae.

Nicotinamide adenine dinucleotide synthetase enzyme (NadE) catalyzes the amination of nicotinic acid adenine dinucleotide (NaAD) to form NAD(+). This reaction represents the last step in the majority of the NAD(+) biosynthetic routes described to date. NadE enzymes typically use either glutamine or ammonium as amine nitrogen donor, and the reaction is energetically driven by ATP hydrolysis. Given the key role of NAD(+) in bacterial metabolism, NadE has attracted considerable interest as a potential target for the development of novel antibiotics. The plant-associative nitrogen-fixing bacteria Herbaspirillum seropedicae encodes two putative NadE, namely nadE1 and nadE2. The nadE1 gene is linked to glnB encoding the signal transduction protein GlnB. Here we report the purification and in vitro characterization of H. seropedicae NadE1. Gel filtration chromatography analysis suggests that NadE1 is an octamer. The NadE1 activity was assayed in vitro, and the Michaelis-Menten constants for substrates NaAD, ATP, glutamine and ammonium were determined. Enzyme kinetic and in vitro substrate competition assays indicate that H. seropedicae NadE1 uses glutamine as a preferential nitrogen donor.

Garcinia gardneriana (Planchon & Triana) Zappi. (Clusiaceae) as a topical anti-inflammatory alternative for cutaneous inflammation.

Garcinia gardneriana is popularly used in skin disorders; therefore, this article investigated the effect of G. gardneriana extracts from leaves, bark and seeds and two isolated compounds in ear oedema and leucocytes migration caused by croton oil. The topical application of the extract of G. gardneriana leaves was able to reduce (70 ± 3%, and ID(50) 0.33 mg/ear) ear oedema, while the seeds (51 ± 5%) and the wood (60 ± 12%) extracts were less effective. In a time-course evaluation, the leaf extract (1 mg/ear) was effective when applied 2 hr before and until 3 hr after the stimulation, presenting a higher effectiveness when applied right after croton oil (83 ± 7% inhibition). In addition, the leaf extract was able to diminish the myeloperoxidase (MPO) activity in 64 ± 13%, which suggests the inhibition of leucocyte infiltration that was confirmed by histological analysis. Also, both biflavonoids isolated from the leaves of G. gardneriana, fukugetin (or morelloflavone) and 13-naringenin-II 8-eriodictyol (GB-2a), were able to reduce ear oedema, with ID(50) values of 0.18 (0.10-0.28) and 0.22 (0.15-0.31) mg/ear, respectively, besides the inhibition of MPO activity of 52 ± 6% and 64 ± 5%, respectively. Using the fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate, the leaf extract, fukugetin and GB-2a topically applied to the ear treated with croton oil reduced 52 ± 15%, 63 ± 17% and 83 ± 4%, respectively, the production of reactive oxygen species of the skin. Thus, these results reveal the anti-inflammatory effect of G. gardneriana leaves for topical usage, and both biflavonoids are responsible for this effect.