Nanoparticle (NP)-based therapeutics have ushered in a new era in translational medicine. However, despite the clinical success of NP technology, it is not well-understood how NPs fundamentally ...change in biological environments. When introduced into physiological fluids, NPs are coated by proteins, forming a protein corona (PC). The PC has the potential to endow NPs with a new identity and alter their bioactivity, stability, and destination. Additionally, the conformation of proteins is sensitive to their physical and chemical surroundings. Therefore, biological factors and protein-NP-interactions can induce changes in the conformation and orientation of proteins
in vivo
. Since the function of a protein is closely connected to its folded structure, slight differences in the surrounding environment as well as the surface characteristics of the NP materials may cause proteins to lose or gain a function. As a result, this can alter the downstream functionality of the NPs. This review introduces the main biological factors affecting the conformation of proteins associated with the PC. Then, four types of NPs with extensive utility in biomedical applications are described in greater detail, focusing on the conformation and orientation of adsorbed proteins. This is followed by a discussion on the instances in which the conformation of adsorbed proteins can be leveraged for therapeutic purposes, such as controlling protein conformation in assembled matrices in tissue, as well as controlling the PC conformation for modulating immune responses. The review concludes with a perspective on the remaining challenges and unexplored areas at the interface of PC and NP research.
Representation of the influence of biological and nanoscale factors on protein corona conformation and function in a healthy
versus
a pathogenic biological environment.
Zebrafish (Danio rerio) is an emerging toxicity screening model for both human health and ecology. As part of the Computational Toxicology Research Program of the U.S. EPA, the toxicity of the 309 ...ToxCast™ Phase I chemicals was assessed using a zebrafish screen for developmental toxicity. All exposures were by immersion from 6–8h post fertilization (hpf) to 5 days post fertilization (dpf); nominal concentration range of 1nM–80μM. On 6dpf larvae were assessed for death and overt structural defects. Results revealed that the majority (62%) of chemicals were toxic to the developing zebrafish; both toxicity incidence and potency was correlated with chemical class and hydrophobicity (logP); and inter-and intra-plate replicates showed good agreement. The zebrafish embryo screen, by providing an integrated model of the developing vertebrate, compliments the ToxCast assay portfolio and has the potential to provide information relative to overt and organismal toxicity.
The conversion of oleic acid (C18:1) to linoleic acid (C18:2) in the endoplasmic reticulum is critical to the accumulation of polyunsaturated fatty acids in seeds and other tissues, and this reaction ...is catalyzed by a Δ12-desaturase, FATTY ACID DESATURASE2 (FAD2). Here, we report that the tomato (
) genome harbors two genes,
and
, which encode proteins with in vitro Δ12-desaturase activity. In addition, tomato has seven divergent FAD2 members that lack Δ12-desaturase activity and differ from canonical FAD2 enzymes at multiple amino acid positions important to enzyme function. Whereas
and
are downregulated by biotic stress, the majority of divergent
genes in tomato are upregulated by one or more stresses. In particular,
is induced by the potato aphid (
) and has elevated constitutive expression levels in
(
), a tomato mutant with enhanced aphid resistance and altered fatty acid profiles. Virus-induced gene silencing of
in
results in significant increases in aphid population growth, indicating that a divergent
gene contributes to aphid resistance in this genotype. Thus, the
gene family in tomato is important both to primary fatty acid metabolism and to responses to biotic stress.
Altered dopaminergic signaling causes behavioral changes in mammals. In general, dopaminergic receptor agonists increase locomotor activity, while antagonists decrease locomotor activity. In order to ...determine if zebrafish (a model organism becoming popular in pharmacology and toxicology) respond similarly, the acute effects of drugs known to target dopaminergic receptors in mammals were assessed in zebrafish larvae. Larvae were maintained in 96-well microtiter plates (1 larva/well). Non-lethal concentrations (0.2–50μM) of dopaminergic agonists (apomorphine, SKF-38393, and quinpirole) and antagonists (butaclamol, SCH-23390, and haloperidol) were administered at 6days post-fertilization (dpf). An initial experiment identified the time of peak effect of each drug (20–260min post-dosing, depending on the drug). Locomotor activity was then assessed for 70min in alternating light and dark at the time of peak effect for each drug to delineate dose-dependent effects. All drugs altered larval locomotion in a dose-dependent manner. Both the D1- and D2-like selective agonists (SKF-38393 and quinpirole, respectively) increased activity, while the selective antagonists (SCH-23390 and haloperidol, respectively) decreased activity. Both selective antagonists also blunted the response of the larvae to changes in lighting conditions at higher doses. The nonselective drugs had biphasic effects on locomotor activity: apomorphine increased activity at the low dose and at high doses, while butaclamol increased activity at low to intermediate doses, and decreased activity at high doses. This study demonstrates that (1) larval zebrafish locomotion can be altered by dopamine receptor agonists and antagonists, (2) receptor agonists and antagonists generally have opposite effects, and (3) drugs that target dopaminergic receptors in mammals appear, in general, to elicit similar locomotor responses in zebrafish larvae.
► Larval locomotion was altered by dopamine receptor agonists and antagonists. ► Receptor agonists and antagonists generally had opposite effects. ► Larval zebrafish are promising models for dopamine behavioral pharmacology.
Developing an efficient transformation system is vital in genetically engineering recalcitrant crops, particularly trees. Here, we outline an
Agrobacterium tumefaciens
-based stable plant ...transformation methodology for citrus genetic engineering. The process was optimized to suit the requirements of fourteen citrus varieties by establishing appropriate infection, co-cultivation, selection, and culture media conditions. The procedure includes transforming seedling-derived epicotyl segments with an
A. tumefaciens
strain, then selecting and regenerating transformed tissues. Transgenic shoots were further identified by a visual reporter (e.g., β-glucuronidase) and confirmed by Northern and Southern blot analysis. Transgene integrations among the transgenic lines ranged between one to four. The methodology can yield transformation efficiencies of up to 11%, and transgenic plants can be recovered as early as six months, depending on the variety. In addition, we show that incorporating
A. tumefaciens
helper virulence genes (
vir
G and
vir
E), spermidine, and lipoic acid in the resuspension buffer before transformation improved the transformation efficiency of specific recalcitrant cultivars, presumably by enhancing T-DNA integration and alleviating oxidative stress on the explant tissues. In conclusion, the optimized methodology can be utilized to engineer diverse recalcitrant citrus varieties towards trait improvement or functional genetics applications.
The increasing use of zebrafish (
Danio rerio) in developmental research highlights the need for a detailed understanding of their behavior. We studied the locomotion of individual zebrafish larva (6 ...days post-fertilization) in 96-well microtiter plates. Movement was recorded using a video-tracking system. Time of day results indicated locomotion, tested in darkness (infrared), decreased gradually from early morning to a stable level between 13:00 and 15:30
h. All further studies were conducted in early-to-late afternoon and lasted approximately 1
h. Each study also began with a period of darkness to minimize any unintended stimulation caused by transferring the plates to the recording platform. Locomotion in darkness increased initially to a maximum at 4
min, then decreased steadily to a low level by 20
min. Locomotion during light was initially low and then gradually increased to a stable level after 20
min. When 10-min periods of light and dark were alternated, activity was low in light and high in dark; curiously, activity during alternating dark periods was markedly higher than originally obtained during either extended dark or light. Further experiments explored the variables influencing this alternating pattern of activity. Varying the duration of the initial dark period (10–20
min) did not affect subsequent activity in either light or dark. The activity increase on return to dark was, however, greater following 15
min than 5
min of light. Acute ethanol increased activity at 1 and 2% and severely decreased activity at 4%. One-percent ethanol retarded the transition in activity from dark to light, and the habituation of activity in dark, while 2% ethanol increased activity regardless of lighting condition. Collectively, these results show that locomotion in larval zebrafish can be reliably measured in a 96-well microtiter plate format, and is sensitive to time of day, lighting conditions, and ethanol.
Ultrasound has been used for the last 50 y in different processing applications. Depending on the power and frequency of the sound waves, ultrasound techniques can be classified in different ...categories. Low-intensity ultrasound uses high frequencies in the range of 100 kHz to 10 MHz and is mostly used for therapeutic purpose (frequencies between 1 and 10 MHz) and to passively monitor the characteristics of materials (frequencies between 100 kHz and 10 MHz). High-intensity ultrasound (HIU), on the other hand, uses lower frequencies in the range of 20 to 100 kHz and it is commonly used for cleaning, disrupting, and restructuring materials. The objective of this study is to evaluate the effect of HIU on functional properties of anhydrous milk fat (AMF), palm kernel oil (PKO), and an all-purpose shortening (Sh). Results from this research shows that HIU induced primary and secondary nucleation in the lipid, generating smaller crystals and as a consequence harder materials. HIU affected hardness more efficiently when applied at higher crystallization temperatures (26 and 28 °C) as shown for AMF data, and when the sonication was applied after the first crystals were formed as observed for PKO and Sh systems. In addition to changes in hardness, AMF and Sh networks obtained after sonication were characterized by a steeper and sharper melting profile. This research shows that HIU can be used as an additional processing tool to tailor the functional properties of lipids with the potential to be used in the processing of trans-free shortenings.
Abstract Guava ( Psidium guajava L.) is a semi-domesticated fruit tree of moderate importance in the Neotropics, utilized for millennia due to its nutritional and medicinal benefits, but its origin ...of domestication remains unknown. In this study, we examine genetic diversity and population structure in 215 plants from 11 countries in Mesoamerica, the Andes, and Amazonia using 25 nuclear microsatellite loci to propose an origin of domestication. Genetic analyses reveal one gene pool in Mesoamerica (Mexico) and four in South America (Brazilian Amazonia, Peruvian Amazonia and Andes, and Colombia), indicating greater differentiation among localities, possibly due to isolation between guava populations, particularly in the Amazonian and Andean regions. Moreover, Mesoamerican populations show high genetic diversity, with moderate genetic structure due to gene flow from northern South American populations. Dispersal scenarios suggest that Brazilian Amazonia is the probable origin of guava domestication, spreading from there to the Peruvian Andes, northern South America, Central America, and Mexico. These findings present the first evidence of guava domestication in the Americas, contributing to a deeper understanding of its evolutionary history.
Plant-based heterologous expression systems can be leveraged to produce high-value therapeutics, industrially important proteins, metabolites, and bioproducts. The production can be scaled up, free ...from pathogen contamination, and offer post-translational modifications to synthesize complex proteins. With advancements in molecular techniques, transgenics, CRISPR/Cas9 system, plant cell, tissue, and organ culture, significant progress has been made to increase the expression of recombinant proteins and important metabolites in plants. Methods are also available to stabilize RNA transcripts, optimize protein translation, engineer proteins for their stability, and target proteins to subcellular locations best suited for their accumulation. This mini-review focuses on recent advancements to enhance the production of high-value metabolites and proteins necessary for therapeutic applications using plants as bio-factories.
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