Taxonomy, fermentation, biological activities, isolation and characterization of metabolites obtained from a new strain of <i style="">Streptomyces noursei</i> (KC46)

212-218An isolate, KC46 active against clinical resistant strains was isolated from Indian soil. Based on morphological features and biochemical characteristics it was identified as Streptomyces noursei. The active compounds isolated from KC46 using various fermentation methods (fermentation in shake flasks, in P-flasks, and also in a fermenter, using starch casein nitrate medium containing zinc sulphate) were characterized based on spectral data. The sulfur rich peptide, nosiheptide and related antibiotics were identified. Nosiheptide has been reported for the first time from a strain of S. noursei

Optimizing natural products by biosynthetic engineering: discovery of nonquinone Hsp90 inhibitors

A biosynthetic medicinal chemistry approach was applied to the optimization of the natural product Hsp90 inhibitor macbecin. By genetic engineering, mutants have been created to produce novel macbecin analogues including a nonquinone compound (5) that has significantly improved binding affinity to Hsp90 (Kd 3 nM vs 240 nM for macbecin) and reduced toxicity (MTD > or = 250 mg/kg). Structural flexibility may contribute to the preorganization of 5 to exist in solution in the Hsp90-bound conformation

TOI-1670 c, a 40 day Orbital Period Warm Jupiter in a Compact System, Is Well Aligned

We report the measurement of the sky-projected obliquity angle λ of the warm Jovian exoplanet TOI-1670 c via the Rossiter-McLaughlin effect. We observed the transit window during UT 2023 April 20 for 7 continuous hours with NEID on the 3.5 m WIYN Telescope at Kitt Peak National Observatory. TOI-1670 hosts a sub-Neptune (P ∼ 11 days; planet b) interior to the warm Jovian (P ∼ 40 days; planet c), which presents an opportunity to investigate the dynamics of a warm Jupiter with an inner companion. Additionally, TOI-1670 c is now among the longest-period planets to date to have its sky-projected obliquity angle measured. We find planet c is well aligned to the host star, with λ = − 0.°3 ± 2.°2. TOI-1670 c joins a growing census of aligned warm Jupiters around single stars and aligned planets in multiplanet systems. © 2023. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The Aligned Orbit of WASP-148b, the only Known Hot Jupiter with a nearby Warm Jupiter Companion, from NEID and HIRES

We present spectroscopic measurements of the Rossiter-McLaughlin effect for WASP-148b, the only known hot Jupiter with a nearby warm-Jupiter companion, from the WIYN/NEID and Keck/HIRES instruments. This is one of the first scientific results reported from the newly commissioned NEID spectrograph, as well as the second obliquity constraint for a hot Jupiter system with a close-in companion, after WASP-47. WASP-148b is consistent with being in alignment with the sky-projected spin axis of the host star, with λ=-8.°2-9.°7+8.°7 . The low obliquity observed in the WASP-148 system is consistent with the orderly-alignment configuration of most compact multi-planet systems around cool stars with obliquity constraints, including our solar system, and may point to an early history for these well-organized systems in which migration and accretion occurred in isolation, with relatively little disturbance. By contrast, previous results have indicated that high-mass and hot stars appear to more commonly host a wide range of misaligned planets: not only single hot Jupiters, but also compact systems with multiple super-Earths. We suggest that, to account for the high rate of spin-orbit misalignments in both compact multi-planet and isolated-hot-Jupiter systems orbiting high-mass and hot stars, spin-orbit misalignments may be caused by distant giant planet perturbers, which are most common around these stellar types. © 2022. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]