Parasite‐Based Screening and Proteome Profiling Reveal Orlistat,an FDA‐Approved Drug,as a Potential Anti Trypanosoma brucei Agent[ ]

Trypanosoma brucei is a parasite that causes African sleeping sickness in humans and nagana in livestock and is transmitted by the tsetse fly. There is an urgent need for the development of new drugs against African trypanosomiasis due to the lack of vaccines and effective drugs. Orlistat (also called tetrahydrolipstatin or THL) is an FDA‐approved antiobesity drug targeting primarily the pancreatic and gastric lipases within the gastrointestinal tract. It shows potential activities against tumors, mycobacteria, and parasites. Herein, we report the synthesis and evaluation of an expanded set of orlistat‐like compounds, some of which showed highly potent trypanocidal activities in both the bloodstream form (BSF) and the procyclic form (PCF) of T. brucei. Subsequent in situ parasite‐based proteome profiling was carried out to elucidate potential cellular targets of the drug in both forms. Some newly identified targets were further validated by the labeling of recombinantly expressed enzymes in Escherichia coli lysates. Bioimaging experiments with a selected compound were carried out to study the cellular uptake of the drug in T. brucei. Results indicated that orlistat is much more efficiently taken up by the BSF than the PCF of T. brucei and has clear effects on the morphology of mitochondria, glycosomes, and the endoplasmic reticulum in both BSF and PCF cells. These results support specific effects of orlistat on these organelles and correlate well with our in situ proteome profiling. Given the economic challenges of de novo drug development for neglected diseases, we hope that our findings will stimulate further research towards the conversion of orlistat‐like compounds into new trypanocidal drugs.     

Upscaling the interplay between diffusion and polynomial drifts through a composite thin strip with periodic microstructure

Meccanica - We study the upscaling of a system of many interacting particles through a heterogenous thin elongated obstacle as modeled via a two-dimensional diffusion problem with a one-directional...     

Robust sensor fault estimation for fractional-order systems with monotone nonlinearities

Nonlinear Dynamics - This paper investigates the problem of sensor fault estimation for systems with monotone nonlinearities and unknown inputs. To the best of our knowledge, such a particular...     

Hydrodynamic Models with Quantum Corrections

We derive a quantum-corrected hydrodynamic and drift-diffusion model for the out-of-equilibrium particle dynamics in the presence of particle collisions, modeled by a BGK collision term. The quantum mechanical corrections are obtained within the Liouville formalism and are expressed by an effective nonlinear force. The Boltzmann and Fermi-Dirac statistics are included.     

Employing perichromism for probing the properties of carboxymethyl cellulose films: an expedient, accurate method for the determination of the degree of substitution of the biopolymer derivative

The properties of films of carboxymethyl cellulose, CMC, of different degree of substitution, DS, have been examined by the use of perichromic indicators (probes). The film properties that have been determined are: empirical polarity, E_T(33); “acidity”, α; “basicity”, β; and dipolarity/polarizability, π*. This has been achieved by employing the following perichromic probes: 4-nitroaniline, 4-nitroanisole, 4-nitro-N,N-dimethylaniline, and 2,6-dichloro-4-(2,4,6-triphenyl-pyridinium-1-yl)phenolate, WB. The correlations between both E_T(33)- or π* and DS were found to be linear; that between β and DS is a second order polynomial; no obvious correlation was found between α and DS. The polarities of CMC films are in the range of those of butyl alcohols. As models for CMC, we have employed cellulose plus CMC of high DS; oxidized cellulose with degree of oxidation = 0.5; sodium glucuronate. The former model behaved akin to CMC, but the plots of the perichromic properties versus DS showed different slopes/intercepts. FTIR data and molecular dynamics simulations on the solvation of WB have shown that this difference can be traced to more efficient hydrogen bonding between the film of the model and the probe. This affects the intra-molecular charge-transfer energy of the latter, leading to different responses to the variation of DS. Based on the excellent linear correlation between E_T(33) and DS, for CMC from different origins, we suggest that perichromism is a simple, accurate, and expedient alternative for the determination of DS of the biopolymer derivative.     

Fundamental solutions and asymptotic numerical methods for bifurcation analysis of nonlinear bi‐harmonic problems

New algorithms, combining asymptotic numerical method (ANM) and method of fundamental solutions, are proposed to compute bifurcation points on branch solutions of a nonlinear bi‐harmonic problem. Three methods, mainly based on asymptotic developments framework, are then proposed. The first one consists in exploiting the ANM step accumulation close to the bifurcation points on a solution branch, the second method allows the introduction of an indicator that vanishes at the bifurcation points, and finally the first real root of the Padé approximant denominator represents the third bifurcation indicator. Two numerical examples are considered to analyze the robustness of these algorithms.     

Elucidation of the Intersystem Crossing Mechanism in a Helical BODIPY for Low‐Dose Photodynamic Therapy

Intersystem crossing (ISC) of triplet photosensitizers is a vital process for fundamental photochemistry and photodynamic therapy (PDT). Herein, we report the co‐existence of efficient ISC and long triplet excited lifetime in a heavy atom‐free bodipy helicene molecule. Via theoretical computation and time‐resolved EPR spectroscopy, we confirmed that the ISC of the bodipy results from its twisted molecular structure and reduced symmetry. The twisted bodipy shows intense long wavelength absorption (?=1.76×10⁵ m ^?1 cm^?1 at 630 nm), satisfactory triplet quantum yield (Φ_T=52 %), and long‐lived triplet state (τ_T=492 μs), leading to unprecedented performance as a triplet photosensitizer for PDT. Moreover, nanoparticles constructed with such helical bodipy show efficient PDT‐mediated antitumor immunity amplification with an ultra‐low dose (0.25 μg kg^?1), which is several hundred times lower than that of the existing PDT reagents.     

Synthesis of furo[3,2-g]chromones under microwave irradiation and their antitumor activity evaluation

A series of furo[3,2-g]chromone derivatives were synthesized via the reaction of furochromone carbaldehyde 1 with amines 3a - d and thioglycolic acid to give thiazolidinones 4a - d . The later react with benzaldehyde/thiourea or hydroxylamine and DMF-DMA in glacial acetic acid to give thiazolopyrimidines 5a - d or thiazoloisoxazoles 6a - d , respectively. Also, the synthesis of α-aminophosphonates via the one-pot reaction of 1 and amines 3a , b were trapped by dialkylphosphites 7a - c afforded the corresponding α-aminophosphonates 8a - f . Applying hexaalkyltriamidophosphites 9a , b to 1 gives alkylidenephosphorane ylides 11a , b in an open structure form. In the present investigation, the in vitro inhibition capacity of compounds ( 4a , 4c , 5b , 5c , 6b - d , 8a - f , and 11a ) was screened in three human cancer cell lines HCT-116, MCF-7, and HepG2. The anticancer activity results revealed that 8b and 8e had more potent cytotoxic inhibition activity against HCT-116 cell line; however, all the tested compounds had obviously less cytotoxic activity against MCF-7 cell line, while 5b , 5c , and 6d were potent against HepG2 cell line compared with that of doxorubicin.