The circadian clock of cyanobacteria, which predicts daily environmental changes, typically includes a standard oscillator consisting of proteins KaiA, KaiB, and KaiC. However, several cyanobacteria have diverse Kai protein homologs of unclear function. In particular, Synechocystis sp.
View Article and Find Full Text PDFCovering 1986 to presentNatural product drug discovery at Novartis has a long and successful history of delivering life saving medicines to millions of patients. In this viewpoint, we are presenting the tools we use and challenges we face as we advance natural products from early research into development and beyond. We are leveraging our collection of 90 000 microbial strains and 20 000 isolated natural products to find new medications in an interdisciplinary approach that requires expertise in microbiology, computational biology, synthetic biology, chemistry, and process development.
View Article and Find Full Text PDFArtificial or non-nutritive sweeteners are indigestible by most animals. Some sweeteners are orally toxic to insects and have received recent interest as potential safe insecticides due to their low mammalian toxicity. In this study, we investigated the oral toxicity of sucralose on insecticide-susceptible and resistant German cockroaches, Blattella germanica (L.
View Article and Find Full Text PDFBiological processes are typically actuated by dynamic multi-subunit molecular complexes. However, interactions between subunits, which govern the functions of these complexes, are hard to measure directly. Here, we develop a general approach combining cryo-EM imaging technology and statistical modeling and apply it to study the hexameric clock protein KaiC in Cyanobacteria.
View Article and Find Full Text PDFThe cellular cytoskeleton relies on diverse populations of motors, filaments, and binding proteins acting in concert to enable nonequilibrium processes ranging from mitosis to chemotaxis. The cytoskeleton's versatile reconfigurability, programmed by interactions between its constituents, makes it a foundational active matter platform. However, current active matter endeavors are limited largely to single force-generating components acting on a single substrate-far from the composite cytoskeleton in cells.
View Article and Find Full Text PDFUrban entomology is the study of arthropod and other pests of the urban environment. It has gained worldwide recognition as a distinct discipline. Its origin is associated with Walter Ebeling's publication in 1975.
View Article and Find Full Text PDFWe investigated insecticide resistance profiles of field populations of the German cockroach, Blattella germanica (L.), collected from central regions of Thailand. Seven strains (PW, RB, MTH, MTS, TL, AY, and SP) were evaluated with diagnostic doses (DD; 3 × LD95 generated from a susceptible strain) of deltamethrin, fipronil, and imidacloprid using topical assays and compared with a susceptible strain (DMSC).
View Article and Find Full Text PDFSelenium, a naturally occurring metalloid, is an essential trace element for many higher organisms, including humans. Humans primarily become exposed to selenium by ingesting food products containing trace amounts of selenium compounds. Although essential in these small amounts, selenium exhibits toxic effects at higher doses.
View Article and Find Full Text PDFThe western yellowjacket, (Saussure), is an important seasonal pest of recreational and outdoor venues in the western United States. Its propensity to scavenge food increases the likelihood of stinging incidences. Control measures are limited to intensive trapping and treating subterranean nests.
View Article and Find Full Text PDFAn estimated 30-70% of available medications in low-income countries and conflict states are of low quality or counterfeit. Reasons for this vary but most are rooted in regulatory agencies being poorly equipped to oversee quality of pharmaceutical stocks. This paper presents the development and validation of a method for point-of-care drug stock quality testing in these environs.
View Article and Find Full Text PDFActive biological molecules present a powerful, yet largely untapped, opportunity to impart autonomous regulation to materials. Because these systems can function robustly to regulate when and where chemical reactions occur, they have the ability to bring complex, life-like behavior to synthetic materials. Here, we achieve this design feat by using functionalized circadian clock proteins, KaiB and KaiC, to engineer time-dependent crosslinking of colloids.
View Article and Find Full Text PDFDue to their mutualistic relationship with plant pests, the Argentine ant is considered a major pest in subtropical fruit orchards and vineyards. Besides insecticide sprays, liquid baiting has been demonstrated as an effective method to suppress the Argentine ant populations. To improve the economic feasibility of liquid baiting, hydrogel materials have been recently tested as a carrier for liquid baits containing various insecticidal active ingredients.
View Article and Find Full Text PDFMicrobial secondary metabolites continue to provide a valuable source of both chemical matter and inspiration for drug discovery in a broad range of therapeutic areas. Beyond this, the corresponding microorganisms represent a sustainable modality for biotechnological production of structurally complex molecules at the quantities required for drug development or even commercial manufacturing. , which has recently been reported as a producer of the pharmacologically highly important G inhibitor FR900359 (FR), represents such an example.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2022
The cyanobacterial clock presents a unique opportunity to understand the biochemical basis of circadian rhythms. The core oscillator, composed of the KaiA, KaiB, and KaiC proteins, has been extensively studied, but a complete picture of its connection to the physiology of the cell is lacking. To identify previously unknown components of the clock, we used KaiB locked in its active fold as bait in an immunoprecipitation/mass spectrometry approach.
View Article and Find Full Text PDFNew infestations of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), were discovered in southern California, namely in Rancho Santa Fe and La Mesa (San Diego County) and Highland Park (Los Angeles County) in 2021. We investigated whether these new infestations were related to the previous infestations in La Mesa (2018) and Canyon Lake, Riverside County (2020). We used two mitochondrial genes (COI and COII) and seven polymorphic microsatellite markers to infer the genetic relationship between southern California colonies and their breeding systems.
View Article and Find Full Text PDFThe composite cytoskeleton, comprising interacting networks of semiflexible actin and rigid microtubules, generates forces and restructures by using motor proteins such as myosins to enable key processes including cell motility and mitosis. Yet, how motor-driven activity alters the mechanics of cytoskeleton composites remains an open challenge. Here, we perform optical tweezers microrheology and confocal imaging of composites with varying actin-tubulin molar percentages (25-75, 50-50, and 75-25), driven by light-activated myosin II motors, to show that motor activity increases the elastic plateau modulus by over 2 orders of magnitude by active restructuring of both actin and microtubules that persists for hours after motor activation has ceased.
View Article and Find Full Text PDFBiological systems have the unique ability to self-organize and generate autonomous motion and work. Motivated by this, we investigate a 2D model colloidal network that can repeatedly transition between disordered states of low connectivity and ordered states of high connectivity rhythmic binding and unbinding of biomimetic crosslinkers. We use Langevin dynamics to investigate the time-dependent changes in structure and collective properties of this system as a function of colloidal packing fractions and crosslinker oscillation periods and characterize the degree of order in the system by using network connectivity, bond length distributions, and collective motion.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2022
Lipopeptides represent a large group of microbial natural products that include important antibacterial and antifungal drugs and some of the most-powerful known biosurfactants. The vast majority of lipopeptides comprise cyclic peptide backbones N-terminally equipped with various fatty acyl moieties. The known compounds of this type are biosynthesized by nonribosomal peptide synthetases, giant enzyme complexes that assemble their products in a non-gene-encoded manner.
View Article and Find Full Text PDFBacterial multimodular polyketide synthases (PKSs) are large enzymatic assembly lines that synthesize many bioactive natural products of therapeutic relevance. While PKS catalysis is mostly based on fatty acid biosynthetic principles, polyketides can be further diversified by post-PKS enzymes. Here, we characterized a remarkably versatile trans-acyltransferase (trans-AT) PKS from Serratia that builds structurally complex macrolides via more than ten functionally distinct PKS modules.
View Article and Find Full Text PDFGel bait insecticides have been extensively used to manage the German cockroach, Blattella germanica (L.) (Blattodea: Ectobiidae), but issues with reduced effectiveness of such formulations are becoming increasingly common. We collected five field strains of German cockroaches in California and evaluated them against five commercial bait products [Maxforce FC Magnum (0.
View Article and Find Full Text PDFA circadian clock can be reconstituted in a test tube using three minimal components from cyanobacteria. A new study has extended this result to include output kinases and a transcription factor. One implication is that the circadian clock may have evolved to function even in a non-growing cell.
View Article and Find Full Text PDFThe cytoskeleton is a model active matter system that controls processes as diverse as cell motility and mechanosensing. While both active actomyosin dynamics and actin-microtubule interactions are key to the cytoskeleton's versatility and adaptability, an understanding of their interplay is lacking. Here, we couple microscale experiments with mechanistic modeling to elucidate how connectivity, rigidity, and force-generation affect emergent material properties in composite networks of actin, tubulin, and myosin.
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