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1.
bioRxiv ; 2024 May 25.
Article in English | MEDLINE | ID: mdl-38826317

ABSTRACT

Cancer-associated fibroblasts (CAFs) play a key role in metabolic reprogramming and are well-established contributors to drug resistance in colorectal cancer (CRC). To exploit this metabolic crosstalk, we integrated a systems biology approach that identified key metabolic targets in a data-driven method and validated them experimentally. This process involved high-throughput computational screening to investigate the effects of enzyme perturbations predicted by a computational model of CRC metabolism to understand system-wide effects efficiently. Our results highlighted hexokinase (HK) as one of the crucial targets, which subsequently became our focus for experimental validation using patient-derived tumor organoids (PDTOs). Through metabolic imaging and viability assays, we found that PDTOs cultured in CAF conditioned media exhibited increased sensitivity to HK inhibition. Our approach emphasizes the critical role of integrating computational and experimental techniques in exploring and exploiting CRC-CAF crosstalk.

2.
J Environ Manage ; 364: 121484, 2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38878567

ABSTRACT

Sustainable soil resource management depends on reliable soil information, often derived from 'legacy soil data' or a combination of old and new soil data. However, the task of harmonizing soil data collected at different times remains a largely unexplored in the literature. Addressing this challenge requires incorporating the temporal dimension into mathematical and statistical models for spatio-temporal soil studies. This study aimed to create a comprehensive framework for harmonizing soil data across various time. We assessed the integration of historical and recent soil data, ranging from 4 to 48 years old data, using soil data recency analysis. To achieve this, we introduced an 'age of data' attribute, calculating the time difference between soil survey years and the present (e.g., 2022). We applied three machine learning models - Decision Trees (DT), Random Forest (RF), Gradient Boosting (GBM) - to a dataset containing 6339 sites and 28,149 depth-harmonized layers. The results consistently demonstrated robust performance across models, RF outperforming with an R-squared value of 0.99, RMSE of 1.41, and a concordance of 0.97. Similarly, DT and GBM also showed strong predictive power. Terrain-derived environmental covariates played a more important role than land use and land cover (LULC) change in predicting soil data recency. While LULC change showed soil organic carbon concentration variability across the different depths, it was a less important factor. Anthropogenic factors, such as LULC change and normalized difference vegetation index (NDVI), were not primary determinants of soil data recency. Variations in soil depth had no impact on predicting soil data recency. This study validated that terrain-derived covariates, especially elevation factors, effectively explain the quality of older soil data when predicting current soil attributes using the soil data recency concept. This approach has the potential to enhance real-time estimates, such as carbon budgets, and we emphasize its importance in global earth system models.

3.
J Theor Biol ; 590: 111857, 2024 Aug 07.
Article in English | MEDLINE | ID: mdl-38797470

ABSTRACT

Resisting apoptosis is a hallmark of cancer. For this reason, it may be possible to force cancer cells to die by targeting components along the apoptotic signaling pathway. However, apoptosis signaling is challenging to understand due to dynamic and complex behaviors of ligands, receptors, and intracellular signaling components in response to cancer therapy. In this work, we forecast the apoptotic response based on the combined impact of these features. We expanded a previously established mathematical model of caspase-mediated apoptosis to include extracellular activation and receptor dynamics. In addition, three potential threshold values of caspase-3 necessary for the activation of apoptosis were selected to forecast which cells become apoptotic over time. We first vary ligand and receptor levels with the number of intracellular signaling proteins remaining consistent. Then, we vary the intracellular protein molecules in each simulated tumor cell to forecast the response of a heterogeneous population. By leveraging the benefits of computational modeling, we investigate the combined effect of several factors on the onset of apoptosis. This work provides quantitative insights for how the apoptotic signaling response can be forecasted, and precisely triggered, amongst heterogeneous cells via extracellular activation.


Subject(s)
Apoptosis , Models, Biological , Neoplasms , Signal Transduction , Humans , Neoplasms/pathology , Neoplasms/metabolism , Caspases/metabolism , Caspase 3/metabolism
5.
Article in English | MEDLINE | ID: mdl-38705863

ABSTRACT

Plant-hummingbird interactions are considered a classic example of coevolution, a process in which mutually dependent species influence each other's evolution. Plants depend on hummingbirds for pollination, whereas hummingbirds rely on nectar for food. As a step towards understanding coevolution, this review focuses on the macroevolutionary consequences of plant-hummingbird interactions, a relatively underexplored area in the current literature. We synthesize prior studies, illustrating the origins and dynamics of hummingbird pollination across different angiosperm clades previously pollinated by insects (mostly bees), bats, and passerine birds. In some cases, the crown age of hummingbirds pre-dates the plants they pollinate. In other cases, plant groups transitioned to hummingbird pollination early in the establishment of this bird group in the Americas, with the build-up of both diversities coinciding temporally, and hence suggesting co-diversification. Determining what triggers shifts to and away from hummingbird pollination remains a major open challenge. The impact of hummingbirds on plant diversification is complex, with many tropical plant lineages experiencing increased diversification after acquiring flowers that attract hummingbirds, and others experiencing no change or even a decrease in diversification rates. This mixed evidence suggests that other extrinsic or intrinsic factors, such as local climate and isolation, are important covariables driving the diversification of plants adapted to hummingbird pollination. To guide future studies, we discuss the mechanisms and contexts under which hummingbirds, as a clade and as individual species (e.g. traits, foraging behaviour, degree of specialization), could influence plant evolution. We conclude by commenting on how macroevolutionary signals of the mutualism could relate to coevolution, highlighting the unbalanced focus on the plant side of the interaction, and advocating for the use of species-level interaction data in macroevolutionary studies.

6.
Curr Pharm Teach Learn ; 16(6): 465-468, 2024 06.
Article in English | MEDLINE | ID: mdl-38582641

ABSTRACT

BACKGROUND AND PURPOSE: To describe one institution's approach to transformation of high-stakes objective structure clinical examinations (OSCEs) from norm-referenced to criterion-referenced standards setting and to evaluate the impact of these changes on OSCE performance and pass rates. EDUCATIONAL ACTIVITY AND SETTING: The OSCE writing team at the college selected a modified Angoff method appropriate for high-stakes assessments to replace the two standard deviation method previously used. Each member of the OSCE writing team independently reviewed the analytical checklist and calculated a passing score for active stations on OSCEs. Then the group met to determine a final pass score for each station. The team also determined critical cut points for each station, when indicated. After administration of the OSCEs, scores, pass rates, and need for remediation were compared to the previous norm-referenced method. Descriptive statistics were used to summarize the data. FINDINGS: OSCE scores remained relatively unchanged when switched to a criterion-referenced method, but the number of remediators increased up to 2.6 fold. In the first year, the average score increased from 86.8% to 91.7% while the remediation rate increased from 2.8% to 7.4%. In the third year, the average increased from 90.9% to 92% while the remediation rate increased from 6% to 15.6%. Likewise, the fourth-year average increased from 84.9% to 87.5% while the remediation rate increased from 4.4% to 9%. SUMMARY: Transition to a modified Angoff method did not impact average OSCE score but did increase the number of remediations.


Subject(s)
Educational Measurement , Humans , Educational Measurement/methods , Educational Measurement/statistics & numerical data , Educational Measurement/standards , Clinical Competence/standards , Clinical Competence/statistics & numerical data , Education, Pharmacy/methods , Education, Pharmacy/standards , Education, Pharmacy/statistics & numerical data
7.
J Am Chem Soc ; 146(15): 10381-10392, 2024 Apr 17.
Article in English | MEDLINE | ID: mdl-38573229

ABSTRACT

DNA cross-links severely challenge replication and transcription in cells, promoting senescence and cell death. In this paper, we report a novel type of DNA interstrand cross-link (ICL) produced as a side product during the attempted repair of 1,N6-ethenoadenine (εA) by human α-ketoglutarate/Fe(II)-dependent enzyme ALKBH2. This stable/nonreversible ICL was characterized by denaturing polyacrylamide gel electrophoresis analysis and quantified by high-resolution LC-MS in well-matched and mismatched DNA duplexes, yielding 5.7% as the highest level for cross-link formation. The binary lesion is proposed to be generated through covalent bond formation between the epoxide intermediate of εA repair and the exocyclic N6-amino group of adenine or the N4-amino group of cytosine residues in the complementary strand under physiological conditions. The cross-links occur in diverse sequence contexts, and molecular dynamics simulations rationalize the context specificity of cross-link formation. In addition, the cross-link generated from attempted εA repair was detected in cells by highly sensitive LC-MS techniques, giving biological relevance to the cross-link adducts. Overall, a combination of biochemical, computational, and mass spectrometric methods was used to discover and characterize this new type of stable cross-link both in vitro and in human cells, thereby uniquely demonstrating the existence of a potentially harmful ICL during DNA repair by human ALKBH2.


Subject(s)
Adenine/analogs & derivatives , Dioxygenases , Ketoglutaric Acids , Humans , Dioxygenases/metabolism , DNA/chemistry , DNA Repair , Ferrous Compounds , DNA Adducts , AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase/metabolism
8.
Inorg Chem ; 63(17): 7619-7630, 2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38629175

ABSTRACT

Arsenic pentafluoride undergoes ligand-induced autoionization in the presence of 1,10-phenanthroline (phen) in a SO2ClF solution to form the donor-stabilized [AsF4(phen)][AsF6] salt. Reacting [AsF4(phen)][AsF6] with the strong Lewis acid SbF5·SO2 yields the mixed arsenic-antimony salt [AsF4(phen)][Sb2F11]. These salts are the first examples of crystallographically characterized donor-stabilized [AsF4]+ cations. The analogous reaction of AsF5 and 2,2'-bipyridine (bipy) does not result in autoionization but leads to the formation of the neutral 2:1 adduct (AsF5)2·bipy. The gas-phase and solution fluoride-ion affinities of [AsF4]+ and [SbF4]+ were calculated, revealing them to be incredibly strong Lewis acids. Density functional theory calculations and natural bond orbital analysis show that significant electron-pair donation from phen to the As center in [AsF4(phen)]+ occurs and quenches the extreme electrophilicity of the [AsF4]+ cation.

9.
Microb Genom ; 10(4)2024 Apr.
Article in English | MEDLINE | ID: mdl-38630608

ABSTRACT

Fungal pathogens commonly originate from benign or non-pathogenic strains living in the natural environment. The recently emerged human pathogen, Candida auris, is one example of a fungus believed to have originated in the environment and recently transitioned into a clinical setting. To date, however, there is limited evidence about the origins of this species in the natural environment and when it began associating with humans. One approach to overcome this gap is to reconstruct phylogenetic relationships between (1) strains isolated from clinical and non-clinical environments and (2) between species known to cause disease in humans and benign environmental saprobes. C. auris belongs to the Candida/Clavispora clade, a diverse group of 45 yeast species including human pathogens and environmental saprobes. We present a phylogenomic analysis of the Candida/Clavispora clade aimed at understanding the ecological breadth and evolutionary relationships between an expanded sample of environmentally and clinically isolated yeasts. To build a robust framework for investigating these relationships, we developed a whole-genome sequence dataset of 108 isolates representing 18 species, including four newly sequenced species and 18 environmentally isolated strains. Our phylogeny, based on 619 orthologous genes, shows environmentally isolated species and strains interspersed with clinically isolated counterparts, suggesting that there have been many transitions between humans and the natural environment in this clade. Our findings highlight the breadth of environments these yeasts inhabit and imply that many clinically isolated yeasts in this clade could just as easily live outside the human body in diverse natural environments and vice versa.


Subject(s)
Candida auris , Candidiasis , Humans , Phylogeny , Candidiasis/microbiology , Candida/genetics , Biological Evolution
10.
Syst Biol ; 2024 Mar 30.
Article in English | MEDLINE | ID: mdl-38554255

ABSTRACT

Why and how organismal lineages radiate is commonly studied through either assessing abiotic factors (biogeography, geomorphological processes, climate) or biotic factors (traits, interactions). Despite increasing awareness that both abiotic and biotic processes may have important joint effects on diversification dynamics, few attempts have been made to quantify the relative importance and timing of these factors, and their potentially interlinked direct and indirect effects, on lineage diversification. We here combine assessments of historical biogeography, geomorphology, climatic niche, vegetative and floral trait evolution to test whether these factors jointly, or in isolation, explain diversification dynamics of a Neotropical plant clade (Merianieae, Melastomataceae). After estimating ancestral areas and the changes in niche and trait disparity over time, we employ Phylogenetic Path Analyses as a synthesis tool to test eleven hypotheses on the individual direct and indirect effects of these factors on diversification rates. We find strongest support for interlinked effects of colonization of the uplifting Andes during the mid-Miocene and rapid abiotic climatic niche evolution in explaining a burst in diversification rate in Merianieae. Within Andean habitats, later increases in floral disparity allowed for the exploitation of wider pollination niches (i.e., shifts from bee to vertebrate pollinators), but did not affect diversification rates. Our approach of including both vegetative and floral trait evolution, rare in assessments of plant diversification in general, highlights that the evolution of woody habit and larger flowers preceded the colonization of the Andes, but was likely critical in enabling the rapid radiation in montane environments. Overall, and in concert with the idea that ecological opportunity is a key element of evolutionary radiations, our results suggest that a combination of rapid niche evolution and trait shifts were critical for the exploitation of newly available niche space in the Andes in the mid-Miocene. Further, our results emphasize the importance of incorporating both abiotic and biotic factors into the same analytical framework if we aim to quantify the relative and interlinked effects of these processes on diversification.

11.
Phys Chem Chem Phys ; 26(11): 8919-8931, 2024 Mar 13.
Article in English | MEDLINE | ID: mdl-38426850

ABSTRACT

Homing endonucleases (HEs) are highly specific DNA cleaving enzymes, with I-PpoI having been suggested to use a single metal to accelerate phosphodiester bond cleavage. Although an I-PpoI mechanism has been proposed based on experimental structural data, no consensus has been reached regarding the roles of the metal or key active site amino acids. This study uses QM cluster and QM/MM calculations to provide atomic-level details of the I-PpoI catalytic mechanism. Minimal QM cluster and large-scale QM/MM models demonstrate that the experimentally-proposed pathway involving direct Mg2+ coordination to the substrate coupled with leaving group protonation through a metal-activated water is not feasible due to an inconducive I-PpoI active site alignment. Despite QM cluster models of varying size uncovering a pathway involving leaving group protonation by a metal-activated water, indirect (water-mediated) metal coordination to the substrate is required to afford this pathway, which renders this mechanism energetically infeasible. Instead, QM cluster models reveal that the preferred pathway involves direct Mg2+-O3' coordination to stabilize the charged substrate and assist leaving group departure, while H98 activates the water nucleophile. These calculations also underscore that both catalytic residues that directly interact with the substrate and secondary amino acids that position or stabilize these residues are required for efficient catalysis. QM/MM calculations on the solvated enzyme-DNA complex verify the preferred mechanism, which is fully consistent with experimental kinetic, structural, and mutational data. The fundamental understanding of the I-PpoI mechanism of action, gained from the present work can be used to further explore potential uses of this enzyme in biotechnology and medicine, and direct future computational investigations of other members of the understudied HE family.


Subject(s)
Endonucleases , Metals , Metals/metabolism , DNA/chemistry , Catalysis , Water
12.
RSC Adv ; 14(10): 6985-6986, 2024 Feb 21.
Article in English | MEDLINE | ID: mdl-38440778

ABSTRACT

Megan O'Mara, Sarah Rauscher and Stacey Wetmore introduce the RSC Advances themed collection on New insights into biomolecular systems from large-scale simulations.

13.
Respirology ; 2024 Mar 04.
Article in English | MEDLINE | ID: mdl-38436522

ABSTRACT

BACKGROUND AND OBJECTIVE: Establishing an accurate and timely diagnosis of idiopathic pulmonary fibrosis (IPF) is essential for appropriate management and prognostication. In some cases, surgical lung biopsy (SLB) is performed but carries non-negligible risk. The objective of this retrospective study was to determine if SLB is associated with accelerated lung function decline in patients with IPF using the Canadian Registry for Pulmonary Fibrosis. METHODS: Linear mixed models and Cox proportional hazards regression models were used to compare decline in forced vital capacity (FVC)%, diffusion capacity of the lung (DLCO%) and risk of death or lung transplantation between SLB and non-SLB patients. Adjustments were made for baseline age, sex, smoking history, antifibrotic use, and lung function. A similar analysis compared lung function changes 12 months pre- and post-SLB. RESULTS: A total of 81 SLB patients and 468 non-SLB patients were included. In the SLB group, the post-biopsy annual FVC% decline was 2.0% (±0.8) in unadjusted, and 2.1% (±0.8) in adjusted models. There was no difference in FVC% decline, DLCO% decline, or time to death or lung transplantation between the two groups, in adjusted or unadjusted models (all p-values >0.07). In the pre-post SLB group, no differences were identified in FVC% decline in unadjusted or adjusted models (p = 0.07 for both). CONCLUSION: No association between SLB and lung function decline or risk of death or lung transplantation was identified in this multi-centre study of patients with IPF.

14.
BMJ Open Respir Res ; 11(1)2024 Mar 13.
Article in English | MEDLINE | ID: mdl-38479819

ABSTRACT

BACKGROUND: Fibrotic interstitial lung disease (ILD) is frequently associated with abnormal oxygenation; however, little is known about the accuracy of oxygen saturation by pulse oximetry (SpO2) compared with arterial blood gas (ABG) saturation (SaO2), the factors that influence the partial pressure of carbon dioxide (PaCO2) and the impact of PaCO2 on outcomes in patients with fibrotic ILD. STUDY DESIGN AND METHODS: Patients with fibrotic ILD enrolled in a large prospective registry with a room air ABG were included. Prespecified analyses included testing the correlation between SaO2 and SpO2, the difference between SaO2 and SpO2, the association of baseline characteristics with both the difference between SaO2 and SpO2 and the PaCO2, the association of baseline characteristics with acid-base category, and the association of PaCO2 and acid-base category with time to death or transplant. RESULTS: A total of 532 patients with fibrotic ILD were included. Mean resting SaO2 was 92±4% and SpO2 was 95±3%. Mean PaCO2 was 38±6 mmHg, with 135 patients having PaCO2 <35 mmHg and 62 having PaCO2 >45 mmHg. Correlation between SaO2 and SpO2 was mild to moderate (r=0.39), with SpO2 on average 3.0% higher than SaO2. No baseline characteristics were associated with the difference in SaO2 and SpO2. Variables associated with either elevated or abnormal (elevated or low) PaCO2 included higher smoking pack-years and lower baseline forced vital capacity (FVC). Lower baseline lung function was associated with an increased risk of chronic respiratory acidosis. PaCO2 and acid-base status were not associated with time to death or transplant. INTERPRETATION: SaO2 and SpO2 are weakly-to-moderately correlated in fibrotic ILD, with limited ability to accurately predict this difference. Abnormal PaCO2 was associated with baseline FVC but was not associated with outcomes.


Subject(s)
Lung Diseases, Interstitial , Oxygen , Humans , Oximetry , Blood Gas Analysis , Lung Diseases, Interstitial/diagnosis
15.
Curr Pharm Teach Learn ; 16(3): 160-166, 2024 03.
Article in English | MEDLINE | ID: mdl-38326192

ABSTRACT

INTRODUCTION: The objective of this study is to describe the workload responsibilities and job satisfaction of skills laboratory faculty, both before and during the COVID-19 pandemic. METHODS: School of pharmacy (SOP) skills laboratory faculty were surveyed in fall 2021 to gather information on workload responsibilities and job satisfaction, before and during the COVID-19 pandemic. Quantitative data were reported using descriptive statistics and, when appropriate, student t-tests were used to compare responses from before and during COVID-19. Qualitative data were coded for themes by two investigators with a third investigator used to reach consensus. RESULTS: A total of 45 skills laboratory faculty from 44 of 142 SOP responded to the survey. Faculty reported an average percent effort of 43.9% laboratory teaching, 13.9% non-laboratory teaching, 12.8% service, 6.5% administration, 12.5% patient care, and 10.4% scholarship. Overall job satisfaction decreased from before COVID-19 to during COVID-19, and faculty members' satisfaction specifically with their laboratory role decreased from 7.5 to 6.6 (P = .003). Several themes were identified when respondents described what they loved most about teaching in the laboratory as well as the challenges associated, the majority of which were personnel, resources, and time. CONCLUSIONS: Skills laboratory faculty reported a high number of laboratory courses coordinated each year along with many hours dedicated each week to prepare and conduct skills laboratory activities. While the pandemic is over, the unique aspects of coordinating student-centered courses likely requires more support for skills laboratory faculty members to avoid burnout and improve job satisfaction.


Subject(s)
Burnout, Professional , COVID-19 , Humans , Pandemics , Faculty , Workload
16.
BMC Bioinformatics ; 25(1): 45, 2024 Jan 29.
Article in English | MEDLINE | ID: mdl-38287239

ABSTRACT

BACKGROUND: Microbial communities play a crucial role in ecosystem function through metabolic interactions. Genome-scale modeling is a promising method to understand these interactions and identify strategies to optimize the community. Flux balance analysis (FBA) is most often used to predict the flux through all reactions in a genome-scale model; however, the fluxes predicted by FBA depend on a user-defined cellular objective. Flux sampling is an alternative to FBA, as it provides the range of fluxes possible within a microbial community. Furthermore, flux sampling can capture additional heterogeneity across a population, especially when cells exhibit sub-maximal growth rates. RESULTS: In this study, we simulate the metabolism of microbial communities and compare the metabolic characteristics found with FBA and flux sampling. With sampling, we find significant differences in the predicted metabolism, including an increase in cooperative interactions and pathway-specific changes in predicted flux. CONCLUSIONS: Our results suggest the importance of sampling-based approaches to evaluate metabolic interactions. Furthermore, we emphasize the utility of flux sampling in quantitatively studying interactions between cells and organisms.


Subject(s)
Genome , Microbiota , Metabolic Networks and Pathways/genetics , Models, Biological , Metabolic Flux Analysis/methods
17.
J Chem Inf Model ; 64(3): 944-959, 2024 Feb 12.
Article in English | MEDLINE | ID: mdl-38253321

ABSTRACT

Endonuclease V (EndoV) is a single-metal-dependent enzyme that repairs deaminated DNA nucleobases in cells by cleaving the phosphodiester bond, and this enzyme has proven to be a powerful tool in biotechnology and medicine. The catalytic mechanism used by EndoV must be understood to design new disease detection and therapeutic solutions and further exploit the enzyme in interdisciplinary applications. This study has used a mixed molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) approach to compare eight distinct catalytic pathways and provides the first proposed mechanism for bacterial EndoV. The calculations demonstrate that mechanisms involving either direct or indirect metal coordination to the leaving group of the substrate previously proposed for other nucleases are unlikely for EndoV, regardless of the general base (histidine, aspartate, and substrate phosphate moiety). Instead, distinct catalytic pathways are characterized for EndoV that involve K139 stabilizing the leaving group, a metal-coordinated water stabilizing the transition structure, and either H214 or a substrate phosphate group activating the water nucleophile. In silico K139A and H214A mutational results support the newly proposed roles of these residues. Although this is a previously unseen combination of general base, general acid, and metal-binding architecture for a one-metal-dependent endonuclease, our proposed catalytic mechanisms are fully consistent with experimental kinetic, structural, and mutational data. In addition to substantiating a growing body of literature, suggesting that one metal is enough to catalyze P-O bond cleavage in nucleic acids, this new fundamental understanding of the catalytic function will promote the exploration of new and improved applications of EndoV.


Subject(s)
Nucleic Acids , Deoxyribonuclease (Pyrimidine Dimer)/chemistry , Deoxyribonuclease (Pyrimidine Dimer)/genetics , Deoxyribonuclease (Pyrimidine Dimer)/metabolism , Lysine , Metals , Phosphates , Water
18.
J Interpers Violence ; 39(3-4): 848-868, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37705463

ABSTRACT

Although the viral nature of videos that capture violent and racialized policing of Black Americans in the United States can increase awareness, exposure to race-based violence can result in vicarious traumatization, particularly among Black Americans. The relationship between anticipatory traumatic reactions (ATRs) and racial identity attitudes is not clearly addressed in the extant body of literature. The current study addresses this research disparity by first analyzing group mean differences among Black Americans (N = 138) who were assigned to audiovisual, written, and imaginal exposure groups. The current study also used a cluster analysis of Black Americans to examine the differences between racial identity attitudes and ATRs following media exposure to undue police violence. Results from the study indicated that no differences in ATRs existed based on types of media exposure. Significant differences across three racial identity clusters existed between ATR in association with attitudes of assimilation, miseducation, self-hatred, anti-dominance, and ethnic-racial salience. Findings from the study suggest that mental health professionals should attend to racial identity attitudes as a relevant factor in how Black American clients experience the psychological impact of media exposure to undue police violence.


Subject(s)
Black or African American , Compassion Fatigue , Police , Violence , Humans , Attitude , Black or African American/psychology , United States , Violence/psychology , Race Factors
19.
ACS Sens ; 8(12): 4756-4764, 2023 Dec 22.
Article in English | MEDLINE | ID: mdl-38063049

ABSTRACT

The ability of guanine (G)-rich DNA to bind toxic lead (Pb2+) ions within a G-quadruplex (GQ) motif is a leading DNA biosensor strategy. A major analytical hurdle for GQ detection of Pb2+ is competitive GQ templating by potassium (K+) ions. We employ the on-strand DNA synthesis of internal fluorescent chalcone surrogates within the 15-mer thrombin binding aptamer (TBA15) to address this challenge. Replacement of thymidine at the 3-position (T3) within TBA15 with an indole-4-hydroxy-indanone (Ind4HI) chalcone strongly decreases K+-GQ stability while enhancing Pb2+-GQ stability to increase Pb2+ binding specificity. The new T3-Ind4HI probe exhibits a 15-fold increase in fluorescence intensity upon binding of Pb2+ by the modified TBA15 and can detect 6.4 nM Pb2+ in the presence of 10 mM K+. Thus, replacement of the T3 residue of TBA15 with the new Ind4HI probe modulates metal ion affinity by native TBA15 to solve the analytical challenge posed by K+ in real water samples for detecting Pb2+ to meet regulatory guidelines by using a GQ biosensor.


Subject(s)
Chalcones , Lead , DNA , Ions , Fluorescent Dyes/chemistry
20.
Front Chem ; 11: 1296787, 2023.
Article in English | MEDLINE | ID: mdl-38053674

ABSTRACT

Accurate information about interactions between group I metals and nucleic acids is required to understand the roles these metals play in basic cellular functions, disease progression, and pharmaceuticals, as well as to aid the design of new energy storage materials and nucleic acid sensors that target metal contaminants, among other applications. From this perspective, this work generates a complete CCSD(T)/CBS data set of the binding energies for 64 complexes involving each group I metal (Li+, Na+, K+, Rb+, or Cs+) directly coordinated to various sites in each nucleic acid component (A, C, G, T, U, or dimethylphosphate). This data have otherwise been challenging to determine experimentally, with highly accurate information missing for many group I metal-nucleic acid combinations and no data available for the (charged) phosphate moiety. Subsequently, the performance of 61 DFT methods in combination with def2-TZVPP is tested against the newly generated CCSD(T)/CBS reference values. Detailed analysis of the results reveals that functional performance is dependent on the identity of the metal (with increased errors as group I is descended) and nucleic acid binding site (with larger errors for select purine coordination sites). Over all complexes considered, the best methods include the mPW2-PLYP double-hybrid and ωB97M-V RSH functionals (≤1.6% MPE; <1.0 kcal/mol MUE). If more computationally efficient approaches are required, the TPSS and revTPSS local meta-GGA functionals are reasonable alternatives (≤2.0% MPE; <1.0 kcal/mol MUE). Inclusion of counterpoise corrections to account for basis set superposition error only marginally improves the computed binding energies, suggesting that these corrections can be neglected with little loss in accuracy when using larger models that are necessary for describing biosystems and biomaterials. Overall, the most accurate functionals identified in this study will permit future works geared towards uncovering the impact of group I metals on the environment and human biology, designing new ways to selectively sense harmful metals, engineering modern biomaterials, and developing improved computational methods to more broadly study group I metal-nucleic acid interactions.

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