Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
590
result(s) for
"Weiss, Jason T"
Sort by:
Palladium-Mediated Dealkylation of N-Propargyl-Floxuridine as a Bioorthogonal Oxygen-Independent Prodrug Strategy
2015
Herein we report the development and biological screening of a bioorthogonal palladium-labile prodrug of the nucleoside analogue floxuridine, a potent antineoplastic drug used in the clinic to treat advanced cancers.
N
-propargylation of the N3 position of its uracil ring resulted in a vast reduction of its biological activity (~6,250-fold). Cytotoxic properties were bioorthogonally rescued in cancer cell culture by heterogeneous palladium chemistry both in normoxia and hypoxia. Within the same environment, the reported chemo-reversible prodrug exhibited up to 1,450-fold difference of cytotoxicity whether it was in the absence or presence of the extracellular palladium source, underlining the precise modulation of bioactivity enabled by this bioorthogonally-activated prodrug strategy.
Journal Article
A direct physical interaction between Nanog and Sox2 regulates embryonic stem cell self-renewal
by
Halbritter, Florian
,
Kousa, Anastasia I
,
Chambers, Ian
in
Animals
,
Cell differentiation
,
Cell Proliferation
2013
Embryonic stem (ES) cell self‐renewal efficiency is determined by the Nanog protein level. However, the protein partners of Nanog that function to direct self‐renewal are unclear. Here, we identify a Nanog interactome of over 130 proteins including transcription factors, chromatin modifying complexes, phosphorylation and ubiquitination enzymes, basal transcriptional machinery members, and RNA processing factors. Sox2 was identified as a robust interacting partner of Nanog. The purified Nanog–Sox2 complex identified a DNA recognition sequence present in multiple overlapping Nanog/Sox2 ChIP‐Seq data sets. The Nanog tryptophan repeat region is necessary and sufficient for interaction with Sox2, with tryptophan residues required. In Sox2, tyrosine to alanine mutations within a triple‐repeat motif (S X T/S Y) abrogates the Nanog–Sox2 interaction, alters expression of genes associated with the Nanog‐Sox2 cognate sequence, and reduces the ability of Sox2 to rescue ES cell differentiation induced by endogenous
Sox2
deletion. Substitution of the tyrosines with phenylalanine rescues both the Sox2–Nanog interaction and efficient self‐renewal. These results suggest that aromatic stacking of Nanog tryptophans and Sox2 tyrosines mediates an interaction central to ES cell self‐renewal.
This paper features a comprehensive proteomic view on the Nanog interactome. Further, it molecularly and functionally defines the intimate interplay of Nanog with another pluripotency determinant Sox2.
Journal Article
Extracellular palladium-catalysed dealkylation of 5-fluoro-1-propargyl-uracil as a bioorthogonally activated prodrug approach
2014
A bioorthogonal organometallic reaction is a biocompatible transformation undergone by a synthetic material exclusively through the mediation of a non-biotic metal source; a selective process used to label biomolecules and activate probes in biological environs. Here we report the
in vitro
bioorthogonal generation of 5-fluorouracil from a biologically inert precursor by heterogeneous Pd
0
catalysis. Although independently harmless, combined treatment of 5-fluoro-1-propargyl-uracil and Pd
0
-functionalized resins exhibits comparable antiproliferative properties to the unmodified drug in colorectal and pancreatic cancer cells. Live-cell imaging and immunoassay studies demonstrate that the cytotoxic activity of the prodrug/Pd
0
-resin combination is due to the
in situ
generation of 5-fluorouracil. Pd
0
-resins can be carefully implanted in the yolk sac of zebrafish embryos and display excellent biocompatibility and local catalytic activity. The
in vitro
efficacy shown by this masking/activation strategy underlines its potential to develop a bioorthogonally activated prodrug approach and supports further
in vivo
investigations.
A bioorthogonal organometallic reaction is a biocompatible and chemospecific process. Here, the authors report the bioorthogonal generation of 5-fluorouracil from a biologically inert alkylated precursor by extracellular palladium catalysis, and assess its antiproliferative properties
in vitro
.
Journal Article
The Kepler Giant Planet Search. I. A Decade of Kepler Planet-host Radial Velocities from W. M. Keck Observatory
by
Howard, Andrew W
,
Brinkman, Casey L
,
Turtelboom, Emma V
in
Extrasolar planets
,
Habitability
,
Jupiter
2024
Despite the importance of Jupiter and Saturn to Earth’s formation and habitability, there has not yet been a comprehensive observational study of how giant exoplanets correlate with the architectural properties of close-in, sub-Neptune-sized exoplanets. This is largely because transit surveys are particularly insensitive to planets at orbital separations ≳1 au, and so their census of Jupiter-like planets is incomplete, inhibiting our study of the relationship between Jupiter-like planets and the small planets that do transit. To investigate the relationship between close-in, small and distant, giant planets, we conducted the Kepler Giant Planet Survey (KGPS). Using the W. M. Keck Observatory High Resolution Echelle Spectrometer, we spent over a decade collecting 2844 radial velocities (RVs; 2167 of which are presented here for the first time) of 63 Sunlike stars that host 157 transiting planets. We had no prior knowledge of which systems would contain giant planets beyond 1 au, making this survey unbiased with respect to previously detected Jovians. We announce RV-detected companions to 20 stars from our sample. These include 13 Jovians ( 0.3MJ
Journal Article
The California Legacy Survey. III. On the Shoulders of (Some) Giants: The Relationship between Inner Small Planets and Outer Massive Planets
by
Knutson, Heather A
,
Howard, Andrew W
,
Fulton, Benjamin J
in
Gas giant planets
,
Jupiter
,
Metallicity
2022
We use a high-precision radial velocity survey of FGKM stars to study the conditional occurrence of two classes of planets: close-in small planets (0.023–1 au, 2–30 M ⊕) and distant giant planets (0.23–10 au, 30–6000 M ⊕). We find that 41−13+15% of systems with a close-in, small planet also host an outer giant, compared to 17.6−1.9+2.4% for stars irrespective of small planet presence. This implies that small planet hosts may be enhanced in outer giant occurrences compared to all stars with 1.7σ significance. Conversely, we estimate that 42−13+17% of cold giant hosts also host an inner small planet, compared to 27.6−4.8+5.8% of stars irrespective of cold giant presence. We also find that more massive and close-in giant planets are not associated with small inner planets. Specifically, our sample indicates that small planets are less likely to have outer giant companions more massive than approximately 120 M ⊕ and within 0.3–3 au, than to have less massive or more distant giant companions, with ∼2.2σ confidence. This implies that massive gas giants within 0.3–3 au may suppress inner small planet formation. Additionally, we compare the host-star metallicity distributions for systems with only small planets and those with both small planets and cold giants. In agreement with previous studies, we find that stars in our survey that only host small planets have a metallicity distribution that is consistent with the broader solar-metallicity-median sample, while stars that host both small planets and gas giants are distinctly metal rich with ∼2.3σ confidence.
Journal Article
Global Epidemiology of Pediatric Severe Sepsis: The Sepsis Prevalence, Outcomes, and Therapies Study
2015
Abstract
Rationale
Limited data exist about the international burden of severe sepsis in critically ill children.
Objectives
To characterize the global prevalence, therapies, and outcomes of severe sepsis in pediatric intensive care units to better inform interventional trials.
Methods
A point prevalence study was conducted on 5 days throughout 2013–2014 at 128 sites in 26 countries. Patients younger than 18 years of age with severe sepsis as defined by consensus criteria were included. Outcomes were severe sepsis point prevalence, therapies used, new or progressive multiorgan dysfunction, ventilator- and vasoactive-free days at Day 28, functional status, and mortality.
Measurements and Main Results
Of 6,925 patients screened, 569 had severe sepsis (prevalence, 8.2%; 95% confidence interval, 7.6–8.9%). The patients’ median age was 3.0 (interquartile range [IQR], 0.7–11.0) years. The most frequent sites of infection were respiratory (40%) and bloodstream (19%). Common therapies included mechanical ventilation (74% of patients), vasoactive infusions (55%), and corticosteroids (45%). Hospital mortality was 25% and did not differ by age or between developed and resource-limited countries. Median ventilator-free days were 16 (IQR, 0–25), and vasoactive-free days were 23 (IQR, 12–28). Sixty-seven percent of patients had multiorgan dysfunction at sepsis recognition, with 30% subsequently developing new or progressive multiorgan dysfunction. Among survivors, 17% developed at least moderate disability. Sample sizes needed to detect a 5–10% absolute risk reduction in outcomes within interventional trials are estimated between 165 and 1,437 patients per group.
Conclusions
Pediatric severe sepsis remains a burdensome public health problem, with prevalence, morbidity, and mortality rates similar to those reported in critically ill adult populations. International clinical trials targeting children with severe sepsis are warranted.
Journal Article
Metabolomics-assisted proteomics identifies succinylation and SIRT5 as important regulators of cardiac function
by
Ryu, Dongryeol
,
Chen, Wei
,
Lin, Hening
in
Acyl Coenzyme A - genetics
,
Acyl Coenzyme A - metabolism
,
Acylation
2016
Cellular metabolites, such as acyl-CoA, can modify proteins, leading to protein posttranslational modifications (PTMs). One such PTM is lysine succinylation, which is regulated by sirtuin 5 (SIRT5). Although numerous proteins are modified by lysine succinylation, the physiological significance of lysine succinylation and SIRT5 remains elusive. Here, by profiling acyl-CoA molecules in various mouse tissues, we have discovered that different tissues have different acyl-CoA profiles and that succinyl-CoA is the most abundant acyl-CoA molecule in the heart. This interesting observation has prompted us to examine protein lysine succinylation in different mouse tissues in the presence and absence of SIRT5. Protein lysine succinylation predominantly accumulates in the heart when Sirt5 is deleted. Using proteomic studies, we have identified many cardiac proteins regulated by SIRT5. Our data suggest that ECHA, a protein involved in fatty acid oxidation, is a major enzyme that is regulated by SIRT5 and affects heart function. Sirt5 knockout (KO) mice have lower ECHA activity, increased long-chain acyl-CoAs, and decreased ATP in the heart under fasting conditions. Sirt5 KO mice develop hypertrophic cardiomyopathy, as evident from the increased heart weight relative to body weight, as well as reduced shortening and ejection fractions. These findings establish that regulating heart metabolism and function is amajor physiological function of lysine succinylation and SIRT5.
Journal Article
Pozzolanic Reactivity of Supplementary Cementitious Materials
by
Isgor, O. Burkan
,
Bharadwaj, Keshav
,
Weiss, W. Jason
in
Aluminum oxide
,
Carbon footprint
,
Carbonates
2023
As the number of potential supplementary cementitious materials (SCMs) increase, there is a need to determine their reactivity. Most recent methods to assess pozzolanic reactivity are based on measuring certain outputs such as heat release (Q), calcium hydroxide (CH) consumption, and nonevaporable water. This paper uses thermodynamic modeling to aid in the interpretation of these tests and the quantifcation of reactivity. It is shown that pozzolanic reactivity should be interpreted based on the SCM type. The presence of sulfates and carbonates during reactivity quantification alter the reaction of the [Al.sub.2][O.sub.3] phases, making the interpretation of the reactivity test results challenging. The reactivity of commercial SCMs should be interpreted specific to the type of SCM as described by ASTM International/AASHTO. A proposed interpretation for commercial SCMs is provided in this paper. Keywords: pozzolanic reactivity test (PRT); reactivity; supplementary cementitious materials (SCMs); thermodynamic modeling.
Journal Article
Pathophysiological Mechanisms by which Heat Stress Potentially Induces Kidney Inflammation and Chronic Kidney Disease in Sugarcane Workers
by
Weiss, Ilana
,
Lucas, Rebekah A. I.
,
Glaser, Jason
in
Adolescent
,
Adult
,
Anti-Inflammatory Agents, Non-Steroidal - adverse effects
2020
Background: Chronic kidney disease of non-traditional origin (CKDnt) is common among Mesoamerican sugarcane workers. Recurrent heat stress and dehydration is a leading hypothesis. Evidence indicate a key role of inflammation. Methods: Starting in sports and heat pathophysiology literature, we develop a theoretical framework of how strenuous work in heat could induce kidney inflammation. We describe the release of pro-inflammatory substances from a leaky gut and/or injured muscle, alone or in combination with tubular fructose and uric acid, aggravation by reduced renal blood flow and increased tubular metabolic demands. Then, we analyze longitudinal data from >800 sugarcane cutters followed across harvest and review the CKDnt literature to assess empirical support of the theoretical framework. Results: Inflammation (CRP elevation and fever) and hyperuricemia was tightly linked to kidney injury. Rehydrating with sugary liquids and NSAID intake increased the risk of kidney injury, whereas electrolyte solution consumption was protective. Hypokalemia and hypomagnesemia were associated with kidney injury. Discussion: Heat stress, muscle injury, reduced renal blood flow and fructose metabolism may induce kidney inflammation, the successful resolution of which may be impaired by daily repeating pro-inflammatory triggers. We outline further descriptive, experimental and intervention studies addressing the factors identified in this study.
Journal Article
Molecular determinants and mechanism for antibody cocktail preventing SARS-CoV-2 escape
by
Ku, Zhiqiang
,
Li, Yize
,
Muruato, Antonio E.
in
631/250/2152/2153/1291
,
631/326/596/4130
,
64/60
2021
Antibody cocktails represent a promising approach to prevent SARS-CoV-2 escape. The determinants for selecting antibody combinations and the mechanism that antibody cocktails prevent viral escape remain unclear. We compared the critical residues in the receptor-binding domain (RBD) used by multiple neutralizing antibodies and cocktails and identified a combination of two antibodies CoV2-06 and CoV2-14 for preventing viral escape. The two antibodies simultaneously bind to non-overlapping epitopes and independently compete for receptor binding. SARS-CoV-2 rapidly escapes from individual antibodies by generating resistant mutations in vitro, but it doesn’t escape from the cocktail due to stronger mutational constraints on RBD-ACE2 interaction and RBD protein folding requirements. We also identified a conserved neutralizing epitope shared between SARS-CoV-2 and SARS-CoV for antibody CoV2-12. Treatments with CoV2-06 and CoV2-14 individually and in combination confer protection in mice. These findings provide insights for rational selection and mechanistic understanding of antibody cocktails as candidates for treating COVID-19.
Antibody cocktails represent a promising approach to prevent SARS-CoV-2 escape. Here, Ku et al., identify SARS-CoV-2 neutralizing antibodies from a phage library and identify an antibody combination that prevents viral escape and protects mice from viral challenge.
Journal Article
This website uses cookies to ensure you get the best experience on our website.