Exploring Scaffold Hopping for Novel 2-(Quinolin-4-yloxy)acetamides with Enhanced Antimycobacterial Activity

Utilizing a scaffold-hopping strategy from the drug candidate telacebec, a novel series of 2-(quinolin-4-yloxy)acetamides was synthesized and evaluated as inhibitors of Mycobacterium tuberculosis (Mtb) growth. These compounds demonstrated potent activity against drug-sensitive and multidrug-resistant strains (MIC ≤ 0.02 μM). Leading compounds were evaluated against a known qcrB resistant strain (T313A), and their loss in activity suggested that the cytochrome bc1 complex is the likely target. Additionally, these structures showed high selectivity regarding mammalian cells (selectivity index > 500) and stability across different aqueous media. Furthermore, some of the synthesized quinolines demonstrated aqueous solubility values that exceeded those of telacebec, while maintaining low rates of metabolism. Finally, a selected compound prevented Mtb growth by more than 1.7 log10 colony forming units in a macrophage model of tuberculosis (TB) infection. These findings validate the proposed design and introduce new 2-(quinolin-4-yloxy)acetamides with potential for development in TB drug discovery campaigns.

Expression of Bacillus amyloliquefaciens transglutaminase in recombinant E. coli under the control of a bicistronic plasmid system in DO-stat fed-batch bioreactor cultivations

We studied the expression of Bacillus amyloliquefaciens transglutaminase cloned in Escherichia coli BL21(DE3)pLysS harboring the plasmid pBAD/3C/bTGase, a bicistronic expression system, in bioreactor cultivation. Batch and fed-batch controlled as DO-stat strategies were employed for the production of the recombinant enzyme. In 30 h-batch cultivations using Terrific broth (TB), 6 g/L of biomass and 3.12 U/mg_protein of transglutaminase activity were obtained. DO-stat fed-batch cultivations under the control of oxygen concentration (DO-stat) using TB as medium but fed with glucose allowed the increment in biomass formation (17.5 g/L) and enzyme activity (6.43 U/mg_protein). DO-stat fed-batch using mineral medium (M9) and fed with glucose under the same conditions produced even higher enzymatic activity (9.14 U/mg_protein). The pH effect was investigated, and the best enzymatic activity could be observed at pH 8. In all cultivations, the bicistronic system remained stable, with 100% of plasmid-bearing cells. These results show that E. coli bearing bicistronic plasmid constructs to express recombinant TGase could be cultivated in bioreactors under DO-stat fed-batch using mineral medium and it is a promising strategy in future optimizations to produce this important enzyme.

Performance consequences of food mixing in two passion vine leaf-footed bugs, Holymenia clavigera (Herbst, 1784) and Anisoscelis foliacea marginella (Dallas, 1852) (Hemiptera; Coreidae)

Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) (Hemiptera: Coreidae: Anisoscelini) are distributed in southern Brazil and use various passion vine species (Passifloraceae) as host-plants. Preliminary observations indicate a high coexistence of these species in terms of host-plant use; in addition, there is a strong similarity regarding egg and nymph morphology. In this study, the most suitable feeding sites for nymph performance on wild (Passiflora suberosa Linnaeus and Passiflora misera Humbold, Bonpland et Kunth) and cultivated (Passiflora edulis Sims) hosts were determined by rearing them on each host and on the combination of hosts. Performance was determined by evaluating nymph development and survivorship, and adult size at emergence. Plant parts used were also recorded. For both species, P. suberosa was the most suitable host plant. First instar nymphs of both species fed on terminal buds more frequently when compared to other plant parts. Second instar nymphs switched to green fruits, whose behavior was more pronounced for H. clavigera. Thus, H. clavigera and A. foliacea marginella immatures are extremely similar in terms of host-plant use and consequences for performance, in addition to their morphological similarity. We suggest that these coreids may have evolved through several processes, including parsimony between the immature stages after speciation, evolutionary convergence, mimicry or genetic drift.