Study on Dynamic Key Management of Clustered Sensor Networks

Study on Dynamic Key Management of Clustered Sensor Network

Novel Tetramic Acids and Pyridone Alkaloids, Militarinones B, C, and D, from the Insect Pathogenic Fungus <i>Paecilomyces </i><i>m</i><i>ilitaris</i>

Three yellow pigments were isolated from a mycelial extract of the entomopathogenic fungus Paecilomyces militaris. With the aid of spectroscopic means, one compound was identified as a new pyridone alkaloid, militarinone D (1). The two other metabolites were characterized as two novel 3-acyl tetramic acids, militarinones B (2) and C (3). In contrast to the structurally related pyridone militarinone A (4), compounds 1−3 showed only negliable neuritogenic activity in PC-12 cells, whereas militarinone D (1) exhibited cytotoxicity. On the basis of a co-occurrence of 3-acyl tetramic acids and biogenetically related pyridone alkaloids in P. militaris, a revised biosynthetic pathway for pyridone alkaloids is proposed

Militarinone A, a Neurotrophic Pyridone Alkaloid from <i>Paecilomyces </i><i>m</i><i>ilitaris</i>¹

A new pyridone alkaloid, militarinone A (1), was isolated by bioassay-guided fractionation from the mycelium of the entomogenous fungus Paecilomyces militaris. Its structure was established by extensive spectroscopic analysis. The compound features an unprecedented side chain and a 1,4-substituted cyclohexyl moiety not previously encountered in microbial metabolites. Militarinone A had a pronounced neurotrophic effect in PC-12 cells at 10 μM concentrations

(+)-<i>N</i>-Deoxymilitarinone A, a Neuritogenic Pyridone Alkaloid from the Insect Pathogenic Fungus <i>Paecilomyces </i><i>f</i><i>arinosus</i>^#

A new pyridone alkaloid, (+)-N-deoxymilitarinone A (1), was isolated from Paecilomyces farinosus RCEF 0097 along with the related metabolites, militarinone D and militarinone B. The sterol 22E,4R-ergosta-7,22-diene-3β,5α,6β,9α-tetraol was also identified. The structures were established by spectroscopic methods, in particular with the aid of extensive NMR experiments. Compound 1 induced neurite sprouting in PC 12 cells when tested at 33 and 100 μM concentrations. A cytotoxic effect was observed in human neurons (IMR-32) at a concentration of 100 μM

Farinosones A−C, Neurotrophic Alkaloidal Metabolites from the Entomogenous Deuteromycete <i>Paecilomyces </i><i>f</i><i>arinosus</i>

Two new yellow pigments, farinosones A (1) and B (2), were isolated from the mycelial extract of the entomogenous fungal strain Paecilomyces farinosus RCEF 0101, together with farinosone C (3), a new metabolite derived from an early step of pyridone alkaloid biosynthesis. The structures were determined by spectroscopic means, in particular by extensive NMR experiments. Compounds 1 and 3 induced neurite outgrowth in the PC-12 cell line at concentrations of 50 μM, while compound 2 was inactive. No cytotoxicity was observed for compounds 1−3 in PC-12 cells when tested at 50 μM concentration in the MTT assay

New Tyrosinase Inhibitors from Paecilomyces gunnii

Through screening 50 strains of entomopathogenic fungi and rescreening of 7 strains of Paecilomyces gunnii, a methanol extract of liquid-cultivated mycelia of P. gunnii was found to have the strongest tyrosinase inhibitory activity. Preparative high-speed counter-current chromatography (HSCCC) guided by high-performance liquid chromatography (HPLC)–electrospray ionization (ESI)–high-resolution mass spectrometry (HRMS) was employed for the isolation and purification of the active components, and three new compounds with half inhibition concentration (IC₅₀) of 0.11, 0.17, and 0.14 mM against diphenolase were obtained from the extract, respectively. Their chemical structures were identified by HRMS, one- and two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy as paecilomycones A, B, and C. Structure and activity studies showed that the tyrosinase inhibition activities are positively related to the number of hydroxyl groups on the paecilomycones