Compounds that exhibit assay interference or undesirable mechanisms of bioactivity are routinely encountered in assays at various stages of drug discovery. We observed that assays for the investigation of thiol-reactive and redox-active compounds have not been collected in a comprehensive review. Here, we review these assays and subject them to experimental optimization to improve their reliability. We demonstrate the usefulness of our assay cascade by assaying a library of bioactive compounds, chemical probes, and a set of approved drugs. These high-throughput assays should complement the array of wet-lab and in silico assays during the initial stages of hit discovery campaigns to pursue only hit compounds with tractable mechanisms of action.

Positive outcomes in biochemical and biological assays of food compounds may appear due to the well-described capacity of some compounds to form colloidal aggregates that adsorb proteins, resulting in their denaturation and loss of function. This phenomenon can lead to wrongly ascribing mechanisms of biological action for these compounds (false positives) as the effect is nonspecific and promiscuous. Similar false positives can show up due to chemical (photo)reactivity, redox cycling, metal chelation, interferences with the assay technology, membrane disruption, etc., which are more frequently observed when the tested molecule has some definite interfering substructures. Although discarding false positives can be achieved experimentally, it would be very useful to have in advance a prognostic value for possible aggregation and/or interference based only in the chemical structure of the compound tested in order to be aware of possible issues, help in prioritization of compounds to test, design of appropriate assays, etc. Previously, we applied cheminformatic tools derived from the drug discovery field to identify putative aggregators and interfering substructures in a database of food compounds, the FooDB, comprising 26,457 molecules at that time. Here, we provide an updated account of that analysis based on a current, much-expanded version of the FooDB, comprising a total of 70,855 compounds. In addition, we also apply a novel machine learning model (SCAM Detective) to predict aggregators with 46-53% increased accuracies over previous models. In this way, we expect to provide the researchers in the mode of action of food compounds with a much improved, robust, and widened set of putative aggregators and interfering substructures of food compounds.

BACKGROUND: This research is one of the very few studies, which seeks a focalized examination to observe the effects of the backpack on the teenager students. Adolescents prefer rucksacks as one of their favorite school bags during their school studies. This study inspects how knapsacks gradually bring changes as injuries in the bodies of school-going adolescents. There are ample studies in the past literature, which evidence the injuries of backpack among adolescents, such as backache, neck pain, and shoulder pain. The principal objective of this study is to determine the effects of backpacks on musculoskeletal injuries among school-going adolescents based on previous studies support in this research field.
METHODS: This review study selected observational studies from the past literature indexed in the databases of Scopus, PubMed, ScienceDirect, and CINAHL during 1999-2020. This review focused on the keywords of \"Backpack,\" \"Musculoskeletal Injuries,\" and \"Adolescent\" from MESH and selected 14 out of 210 articles based on the research objective. According to the Crombie Checklist, inclusion and exclusion criteria, and investigating the quality of the report, this review focused on literature evidence to the field under investigation.
RESULTS: Based on the chosen 14 articles, the findings of the present review indicated two outcomes by considering the impact of the backpack on musculoskeletal injuries and pains among adolescents. The results of the review studies specified that there was a statistically significant positive relationship between the prevalence of musculoskeletal injuries and pain using a backpack among most of the male and female adolescents. The findings also stipulate that injuries and pain intensity among female adolescents were higher than the male students.
CONCLUSIONS: The results of this review study specified that improper use of the backpack, which exceeded the standard weight, caused chorionic pain and injuries between both genders of adolescents. The generalizability of the results is suitable for this review study.

In this study, we sought to determine whether an in vivo assay for studying antibiotic mechanisms of action could provide insight into the activity of compounds that may inhibit multiple targets. Thus, we conducted an activity screen of 31 structural analogs of rhodanine-containing pan-assay interference compounds (PAINS). We identified nine active molecules against Escherichia coli and classified them according to their in vivo mechanisms of action. The mechanisms of action of PAINS are generally difficult to identify due to their promiscuity. However, we leveraged bacterial cytological profiling, a fluorescence microscopy technique, to study these complex mechanisms. Ultimately, we found that although some of our molecules promiscuously inhibit multiple cellular pathways, a few molecules specifically inhibit DNA replication despite structural similarity to related PAINS. A genetic analysis of resistant mutants revealed thymidylate kinase (essential for DNA synthesis) as an intracellular target of some of these rhodanine-containing antibiotics. This finding was supported by in vitro activity assays, as well as experiments utilizing a thymidylate kinase overexpression system. The analog that demonstrated the half-maximal inhibitory concentration in vitro and MIC in vivo displayed the greatest specificity for inhibition of the DNA replication pathway, despite containing a rhodamine moiety. Although it is thought that PAINS cannot be developed as antibiotics, this work showcases novel inhibitors of E. coli thymidylate kinase. Moreover, perhaps more importantly, this work highlights the utility of bacterial cytological profiling for studying the in vivo specificity of antibiotics and demonstrates that bacterial cytological profiling can identify multiple pathways that are inhibited by an individual molecule. IMPORTANCE We demonstrate that bacterial cytological profiling is a powerful tool for directing antibiotic discovery efforts because it can be used to determine the specificity of an antibiotic\'s in vivo mechanism of action. By assaying analogs of PAINS, molecules that are notoriously intractable and nonspecific, we (surprisingly) identify molecules with specific activity against E. coli thymidylate kinase. This suggests that structural modifications to PAINS can confer stronger inhibition by targeting a specific cellular pathway. While in vitro inhibition assays are susceptible to false-positive results (especially from PAINS), bacterial cytological profiling provides the resolution to identify molecules with specific in vivo activity.

Inhibition of amyloid fibril formation could benefit patients with systemic amyloidosis. In this group of diseases, deposition of amyloid fibrils derived from normally soluble proteins leads to progressive tissue damage and organ failure. Amyloid formation is a complex process, where several individual steps could be targeted. Several small molecules have been proposed as inhibitors of amyloid formation. However, the exact mechanism of action for a molecule is often not known, which impedes medicinal chemistry efforts to develop more potent molecules. Furthermore, commonly used assays are prone to artifacts that must be controlled for. Here, potential mechanisms by which small molecules could inhibit aggregation of immunoglobulin light-chain dimers, the precursor proteins for amyloid light-chain (AL) amyloidosis, are studied in assays that recapitulate different aspects of amyloidogenesis in vitro. One molecule reduced unfolding-coupled proteolysis of light chains, but no molecules inhibited aggregation of light chains or disrupted pre-formed amyloid fibrils. This work demonstrates the challenges associated with drug development for amyloidosis, but also highlights the potential to combine therapies that target different aspects of amyloidosis.

Because of the antimicrobial resistance crisis, lectins are considered novel drug targets. Pseudomonas aeruginosa utilizes LecA and LecB in the infection process. Inhibition of both lectins with carbohydrate-derived molecules can reduce biofilm formation to restore antimicrobial susceptibility. Here, we focused on non-carbohydrate inhibitors for LecA to explore new avenues for lectin inhibition. From a screening cascade we obtained one experimentally confirmed hit, a catechol, belonging to the well-known PAINS compounds. Rigorous analyses validated electron-deficient catechols as millimolar LecA inhibitors. The first co-crystal structure of a non-carbohydrate inhibitor in complex with a bacterial lectin clearly demonstrates the catechol mimicking the binding of natural glycosides with LecA. Importantly, catechol 3 is the first non-carbohydrate lectin ligand that binds bacterial and mammalian calcium(II)-binding lectins, giving rise to this fundamentally new class of glycomimetics.

Diabetes mellitus, a progressive chronic disease, characterized by the abnormal carbohydrate metabolism is associated with severe health complications including long term dysfunction or failure of several organs, cardiovascular and micro-angiopathic problems (neuropathy, nephropathy, retinopathy). Despite the existence of diverse chemical structural libraries of α-glucosidase inhibitors, the limited diabetic treatment due to the adverse side effects such as abdominal distention, flatulence, diarrhoea, and liver damage associated with these inhibitors encourage the medicinal research community to design and develop new and potent inhibitors of α-glucosidase with better pharmacokinetic properties. In this perspective, we demonstrate the successful integration of common functional groups (ketone & ester) in one combined pharmacophore which is favorable for the formation of hydrogen bonds and other weaker interactions with the target proteins. These keto ester derivatives were screened for their α-glucosidase inhibition potential and the in vitro results revealed compound 3c as the highly active inhibitor with an IC50 value of 12.4 ± 0.16 μM compared to acarbose (IC50 = 942 ± 0.74 μM). This inhibition potency was ~76-fold higher than acarbose. Other potent compounds were 3f (IC50 = 28.0 ± 0.28 μM), 3h (IC50 = 33.9 ± 0.09 μM), 3g (IC50 = 34.1 ± 0.04 μM), and 3d (IC50 = 76.5 ± 2.0 μM). In addition, the emerging use of carbonic anhydrase inhibitors for the treatment of diabetic retinopathy (a leading cause of vision loss) prompted us to screen the keto ester derivatives for the inhibition of carbonic anhydrase-II. Compound 3b was found significantly active against carbonic anhydrase-II with an IC50 of 16.5 ± 0.92 μM (acetazolamide; IC50 = 18.2 ± 1.23 μM). Compound 3a also exhibited comparable potency with an IC50 value of 18.9 ± 1.08 μM. Several structure-activity relationship analyses depicted the influence of the substitution pattern on both the aromatic rings. Molecular docking analysis revealed the formation of several H-bonding interactions through the ester carbonyl and the nitro oxygens of 3c with the side chains of His348, Arg212 and His279 in the active pocket of α-glucosidase whereas 3b interacted with His95, -OH of Thr197, Thr198 and WAT462 in the active site of carbonic anhydrase-II. Furthermore, evaluation of ADME properties suggests the safer pharmacological profile of the tested derivatives.

Antimalarial candidates possessing novel mechanisms of action are needed to control drug resistant Plasmodium falciparum. We were drawn to Malaria Box compound 1 (MMV665831) by virtue of its excellent in vitro potency, and twelve analogs were prepared to probe its structure-activity relationship. Modulation of the diethyl amino group was fruitful, producing compound 25, which was twice as potent as 1 against cultured parasites. Efforts were made to modify the phenolic Mannich base functionality of 1, to prevent formation of a reactive quinone methide. Homologated analog 28 had reduced potency relative to 1, but still inhibited growth with EC50 ≤ 200 nM. Thus, the antimalarial activity of 1 does not derive from quinone methide formation. Chemical stability studies on dimethyl analog 2 showed remarkable hydrolytic stability of both the phenolic Mannich base and ethyl ester moieties, and 1 was evaluated for in vivo efficacy in P. berghei-infected mice (40 mg/kg, oral). Unfortunately, no reduction in parasitemia was seen relative to control. These results are discussed in the context of measured plasma and hepatocyte stabilities, with reference to structurally-related, orally-efficacious antimalarials.

The mechanistic understanding of the biological effects of foods involves the testing of food compounds in biochemical and biological assays. Positive results in these assays can be artifactual due to some properties of the compound: namely chemical reactivity, membrane disruption, redox cycling, etc., or through the formation of colloidal aggregates. Within the drug discovery field, a wide set of so-called \"nuisance\" filters have been developed to identify substructures prone to assay artifacts and/or promiscuity, e.g., the pan-assay interference compounds (PAINS) and others. In the subarea of natural products, a similar concept is the so-called invalid metabolic panaceas (IMPs). Finally, tools to identify putative aggregators have also been developed. Here, we analyzed the presence of nuisance substructures, IMPs, and aggregators in a large database of food compounds (the FooDB), which should be useful to the researchers working in the field, in order to be aware of possible artifact/promiscuity issues in their assays.

Protein-protein interactions (PPIs) of 14-3-3 proteins are a model system for studying PPI stabilization. The complex natural product Fusicoccin A stabilizes many 14-3-3 PPIs but is not amenable for use in SAR studies, motivating the search for more drug-like chemical matter. However, drug-like 14-3-3 PPI stabilizers enabling such studies have remained elusive. An X-ray crystal structure of a PPI in complex with an extremely low potency stabilizer uncovered an unexpected non-protein interacting, ligand-chelated Mg2+ leading to the discovery of metal-ion-dependent 14-3-3 PPI stabilization potency. This originates from a novel chelation-controlled bioactive conformation stabilization effect. Metal chelation has been associated with pan-assay interference compounds (PAINS) and frequent hitter behavior, but chelation can evidently also lead to true potency gains and find use as a medicinal chemistry strategy to guide compound optimization. To demonstrate this, we exploited the effect to design the first potent, selective, and drug-like 14-3-3 PPI stabilizers.