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Xu, H.

Publications and source records attributed to Xu, H..

At least 271 records · Page 15Linked to original sources

Resting-state functional brain network alternations related to non-suicidal and suicidal self-injurious behaviors in adolescents with depression

Nonsuicidal self-injury (NSSI) and suicidal attempt (SA) frequently occur during depressed adolescents, but the underlying neurobiological mechanisms are poorly understood. The maturation of network connectivity is a central feature of brain development during adolescence. However, few researchers have used resting-state functional magnetic resonance imaging (fMRI) to investigate the similarities and differences in the intrinsic brain networks between NSSI with NSSI+SA in depressed adolescent populations. In this study, we collected self-reported questionnaires and resting-state (fMRI data from a sample of depressed adolescents (N = 114), categorized into three groups: clinical control (non-self-harm), NSSI-only, and NSSI+SA based on their self-harm history. The alternations of FC patterns were identified through support vector machine-based classification, as machine learning approaches can help to overcome the multiple-comparison problems of their multivariate nature. Referring to the convergent alternations between adolescent NSSI with or without a history of SA, the alternations of intra-/inter-network FCs among the Control, SalVAtten, Limbic, and Default networks. Besides, divergent alternations were also observed for depressed adolescents with a history of SA, involving the Limbic, DorsAttn, Visual, and Subcortical networks. Besides, the severity of depressive symptoms only showed a significant correlation with altered FCs in Limbic-DorAttn and Limbic-Visual networks, strengthening the fact that these observed alternations of FC could not all be explained by increased depression severity. The emphasis of this study on the network basis could extend the existing evidence at a circuit level and the observed convergent alternations may explain an underlying neurobiological mechanism pertaining to the continuum of self-destructiveness in adolescents. In addition, our discovery of divergent alternations could help to identify biomarkers that will aid in differentiating those at risk for SA among those engaging in NSSI and contribute to the development of neurobiologically informed interventions.

neuroscience↗

Inhibition mechanism and antiviral activity of an α-ketoamide based SARS-CoV-2 main protease inhibitor

SARS-CoV-2 has demonstrated extraordinary ability to evade antibody immunity by antigenic drift. Small molecule drugs may provide effective therapy while being part of a solution to circumvent SARS-CoV-2 immune escape. In this study we report an -ketoamide based peptidomimetic inhibitor of SARS-CoV-2 main protease (Mpro), RAY1216. Enzyme inhibition kinetic analysis established that RAY1216 is a slow-tight inhibitor with a Ki of 8.6 nM; RAY1216 has a drug-target residence time of 104 min compared to 9 min of PF-07321332 (nirmatrelvir), the antiviral component in Paxlovid, suggesting that RAY1216 is approximately 12 times slower to dissociate from the protease-inhibitor complex compared to PF-07321332. Crystal structure of SARS-CoV-2 Mpro:RAY1216 complex demonstrates that RAY1216 is covalently attached to the catalytic Cys145 through the -ketoamide warhead; more extensive interactions are identified between bound RAY1216 and Mpro active site compared to PF-07321332, consistent with a more stable acyl-enzyme inhibition complex for RAY1216. In cell culture and human ACE2 transgenic mouse models, RAY1216 demonstrates comparable antiviral activities towards different SARS-CoV-2 virus variants compared to PF-07321332. Improvement in pharmacokinetics has been observed for RAY1216 over PF-07321332 in various animal models, which may allow RAY1216 to be used without ritonavir. RAY1216 is currently undergoing phase III clinical trials (https://clinicaltrials.gov/ct2/show/NCT05620160) to test real-world therapeutic efficacy against COVID-19.

biochemistry↗

Dissociable neuronal substrates of visual feature attention and working memory

Attention and working memory (WM) are distinct cognitive functions, yet given their close interactions, it has been proposed that they share the same neuronal mechanisms. Here we show that in macaques performing a WM-guided feature attention task, the activity of most neurons in areas middle temporal (MT), medial superior temporal (MST), lateral intraparietal (LIP), and posterior lateral prefrontal cortex (LPFC-p) displays either WM coding or attentional modulation, but not both. One area thought to play a role in both functions is LPFC-p. To test this, we optogenetically inactivated LPFC-p bilaterally during the attention or WM periods of the task. Attention period inactivation reduced attentional modulation in LPFC-p, MST, and LIP neurons, and impaired task performance. WM period inactivation did not affect attentional modulation nor performance, and minimally reduced WM coding. Our results suggest that feature attention and WM have dissociable neuronal substrates, and that LPFC-p plays a critical role in attention but not WM.

neuroscience↗

Type I interferon dynamics determines memory B cell epigenetic identity in chronic viral infection

Memory B cells are key providers of long-lived immunity against infectious disease, yet in chronic viral infection they do not produce effective protection. How chronic viral infection disrupts memory B cell development, and whether such changes are reversible, remains unknown. Here, we uncover type-I interferon (IFN-I) dynamics as a key determinant in shaping chronic memory B cell development. Through single-cell (sc)ATAC-sequencing and scRNA-sequencing, we identified a unique memory subset enriched for IFN-stimulated genes (ISGs) during chronic lymphocytic choriomeningitis virus infection. Blockade of IFNAR-1 early in infection transformed the chromatin landscape of chronic memory B cells, decreasing accessibility at ISG-inducing transcription factor binding motifs and inducing a phenotypic change in the dominating memory B cell subset. However, timing was critical, with memory B cells resistant to intervention after 4 weeks post-infection. Together, our research identifies a key mechanism to instruct memory B cell identity during viral infection. One Sentence Summary: IFN dynamics in chronic versus acute viral infection determines memory B cell development.

immunology↗

RNPS1 stabilizes NAT10 protein to facilitate translation in cancer via tRNA ac4C modification

NAT10 is dysregulated and plays an essential role in various types of cancers. However, the exact machenism of how NAT10 regulates cancer progression remains debatable. In this report, we show that NAT10 affects tumorigeneis mainly based on its acetylation function on tRNA. In addition, we found NAT10 regulate the ac4C of tRNA in cancer via interaction with RNPS1, which in turn protect NAT10 from degradation by E3 ubiquitin ligase ZSWIM6. We developed TRMC-seq method to compreshensively profile tRNA ac4C sites and uncovered the presence of ac4C in a broader range of tRNA isoacceptors than previous studies. Multi-omics analysis identified AP-1 signaling pathway as a major downstream mediator of NAT10. Mechanistically, we found NAT10 is responsible for the translation efficiency genes which contain higher ac4C-tRNA codon. Importantly, our genetic mouse model validated our in vitro findings of NAT10 in cancer. Our study highlights a role of NAT10 in mediating tRNA ac4C to regulate the translation and tumorigenesis of cancer.

molecular biology↗

Reconstructing cellular differentiation networks and identifying cell fate-determining features with CIBER

Trajectory inference methods are frequently used for cell fate analysis, however, most of them are similarity-based and lack an understanding of the causality underlying differentiation processes. Here, we present CIBER, a Causal Inference-Based framework for the Evaluation of feature effects and the Reconstruction of cellular differentiation networks. CIBER provides a novel paradigm for dissecting cell state transitions other than trajectory inference and differential analysis. It is a versatile framework that can be applied to various types of data, including transcriptomic, epigenomic and microarray data. It can identify both known and potential cell-lineage structures with minimal prior knowledge. By integrating the CIBER-learned network with structural causal model and applying in silico perturbation as inventions, we generated an effect matrix that quantifies the impact of different features on each differentiation branch. Using this effect matrix, CIBER can identify crucial features involved in haematopoiesis, even if these features show no significant difference in expression between lineages. Moreover, CIBER can predict novel regulation associations and provide insight into the potential mechanism underlying the influence of transcription factors on biological processes. To validate CIBERs capabilities, we conducted in vivo experiments on Bcl11b, a non-differentially expressed transcription factor identified by CIBER. Our results demonstrate that dysfunction of Bcl11b leads to a bias towards myeloid lineage differentiation at the expense of lymphoid lineage, which is consistent with our predictions.

systems biology↗

Discovering SARS-CoV-2 neoepitopes and the associated TCR-pMHC recognition mechanisms by combining single-cell sequencing, deep learning, and molecular dynamics simulation techniques

The molecular mechanisms underlying the recognition of epitopes by T cell receptors (TCRs) are critical for activating T cell immune responses and rationally designing TCR-based therapeutics. Single-cell sequencing techniques vastly boost the accumulation of TCR sequences, while the limitation of available TCR-pMHC structures hampers further investigations. In this study, we proposed a comprehensive strategy that incorporates structural information and single-cell sequencing data to investigate the epitope-recognition mechanisms of TCRs. By antigen specificity clustering, we mapped the epitope sequences between epitope-known and epitope-unknown TCRs from COVID-19 patients. One reported SARS-CoV-2 epitope, NQKLIANQF (S919-927), was identified for a TCR expressed by 614 T cells (TCR-614). Epitope screening also identified a potential cross-reactive epitope, KLKTLVATA (NSP31790-1798), for a TCR expressed by 204 T cells (TCR-204). According to the molecular dynamics (MD) simulations, we revealed the detailed epitope-recognition mechanisms for both TCRs. The structural motifs responsible for epitope recognition revealed by the MD simulations are consistent with the sequential features recognized by the sequence-based clustering method. This strategy will facilitate the discovery and optimization of TCR-based therapeutics. In addition, the comprehensive strategy can also promote the development of cancer vaccines in virtue of the ability to discover neoepitopes and epitope-recognition mechanisms.

immunology↗

Gemini: Memory-efficient integration of hundreds of gene networks with high-order pooling

MotivationThe exponential growth of genomic sequencing data has created ever-expanding repositories of gene networks. Unsupervised network integration methods are critical to learn informative representations for each gene, which are later used as features for downstream applications. However, these network integration methods must be scalable to account for the increasing number of networks and robust to an uneven distribution of network types within hundreds of gene networks. ResultsTo address these needs, we present Gemini, a novel network integration method that uses memory-efficient high-order pooling to represent and weight each network according to its uniqueness. Gemini then mitigates the uneven distribution through mixing up existing networks to create many new networks. We find that Gemini leads to more than a 10% improvement in F1 score, 14% improvement in micro-AUPRC, and 71% improvement in macro-AURPC for protein function prediction by integrating hundreds of networks from BioGRID, and that Geminis performance significantly improves when more networks are added to the input network collection, while the comparison approachs performance deteriorates. Gemini thereby enables memory-efficient and informative network integration for large gene networks, and can be used to massively integrate and analyze networks in other domains. AvailabilityGemini can be accessed at: https://github.com/MinxZ/Gemini. Contactaddiewc@cs.washington.edu, swang@cs.washington.edu

bioinformatics↗

Development and characterization of new patient-derived xenograft (PDX) models of osteosarcoma with distinct metastatic capacities

Models to study metastatic disease in rare cancers are needed to advance preclinical therapeutics and to gain insight into disease biology, especially for highly aggressive cancers with a propensity for metastatic spread. Osteosarcoma is a rare cancer with a complex genomic landscape in which outcomes for patients with metastatic disease are poor. As osteosarcoma genomes are highly heterogeneous, a large panel of models is needed to fully elucidate key aspects of disease biology and to recapitulate clinically-relevant phenotypes. We describe the development and characterization of osteosarcoma patient-derived xenografts (PDXs) and a panel of PDX-derived cell lines. Matched patient samples, PDXs, and PDX-derived cell lines were comprehensively evaluated using whole genome sequencing and RNA sequencing. PDXs and PDX-derived cell lines largely maintained the expression profiles of the patient from which they were derived despite the emergence of whole-genome duplication (WGD) in a subset of cell lines. These cell line models were heterogeneous in their metastatic capacity and their tissue tropism as observed in both intravenous and orthotopic models. As proof-of-concept study, we used one of these models to test the preclinical effectiveness of a CDK inhibitor on the growth of metastatic tumors in an orthotopic amputation model. Single-agent dinaciclib was effective at dramatically reducing the metastatic burden in this model. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=74 SRC="FIGDIR/small/524562v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@17ea2a8org.highwire.dtl.DTLVardef@e8fcc7org.highwire.dtl.DTLVardef@2b9f8corg.highwire.dtl.DTLVardef@1f7b802_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

Label-free quantitative proteomics analyses of mouse astrocytes provides insight into the host response mechanism at different developmental stages of Toxoplasma gondii

Toxoplasma gondii (T. gondii) is an opportunistic parasite that can infect the central nervous system (CNS), causing severe toxoplasmosis and behavioral cognitive impairment. Mortality is high in immunocompromised individuals with toxoplasmosis, most commonly due to reactivation of infection in the CNS. There are still no effective vaccines and drugs for the prevention and treatment of toxoplasmosis. There are five developmental stages for T. gondii to complete life cycle, of which the tachyzoite and bradyzoite stages are the key to the acute and chronic infection. In this study, to better understanding of how T. gondii interacts with the host CNS at different stages of infection, we constructed acute and chronic infection models of T. gondii in astrocytes, and used label-free proteomics to detect the proteome changes before and after infection, respectively. A total of 4676 proteins were identified, among which 163 differentially expressed proteins (DEPs) (fold change[≥]1.5 or [≤]0.67 and p-value[≤]0.05) including 109 up-regulated proteins and 54 down-regulated proteins in C8-TA vs C8 group, and 719 DEPs including 495 up-regulated proteins and 224 down-regulated proteins in C8-BR vs C8-TA group. After T. gondii tachyzoites infected astrocytes, DEPs were enriched in immune-related biological processes to promote the formation of bradyzoites and maintain the balance of T. gondii, CNS and brain. After T. gondii bradyzoites infected astrocytes, the DEPs up-regulated the hosts glucose metabolism, and some up-regulated DEPs were closely related to neurodegenerative diseases. These findings not only provide new insights into the psychiatric pathogenesis of T. gondii, but also provide potential targets for the treatment of acute and chronic Toxoplasmosis.

microbiology↗

Bioengineering of a Lactococcus lactis subsp. lactis strain enhances nisin production and bioactivity.

Lactococcus lactis subsp. lactis is a food bacterium that has been utilized for decades in food fermentation and the development of high-value industrial goods. Among these, nisin is produced by several strains of L. lactis subsp. lactis plays a crucial role as a food bio-preservative. The relative expression of the gene cluster involved in nisin production was evaluated using qPCR analysis. Additionally, a series of re-transformations of the strain introducing multi copies of the nisA and nisRK genes involved in nisin biosynthesis were developed. The simultaneous expression of nisA and nisZ genes was used to potentiate the effective inhibition of foodborne pathogens. Further, qPCR analysis revealed a low expression of the nisA and nisRK genes in wild-type L. lactis subsp. lactis. After several re-transformations of the strain with the nisA and nisRK genes, a high expression of these genes was obtained, contributing to improved nisin production. Also, the co-expression of nisA and nisZ genes results in highly efficient antimicrobial activity. Hence, this study would supply an approach to enhancing nisin production during industrial processes and antimicrobial activity.

microbiology↗

Histone acetylation insulator SET orchestrates PP2A inhibition and super-enhancer activation

Wide-spread growth-essential genes are hyper-transcribed in the pancreatic cancer cells. Searching for the factors that reprogram this abnormal transcription, we identified the nuclear oncogene SET that supported CDK9-induced and Pol II-mediated transcription. SET disrupted PP2A-A/C interaction via its C-terminal domains. Through blocking PP2A activity, SET assisted CDK9 to maintain Pol II CTD phosphorylation and activated mRNA transcription. Meanwhile, as a histone acetylation insulator, SET mainly suppressed histone acetylation in the gene promoters but evaded enhancers. Massive super-enhancer associated genes, including the oncogene MET, were hence permitted to be transcribed by SET over-expression. Our findings position SET as a key factor that bridges histone acetylation and PP2A related transcription in cancer cells.

molecular biology↗

The effect of Dnaaf5 gene dosage on primary ciliary dyskinesia phenotypes

DNAAF5 is a dynein motor assembly factor associated with the autosomal heterogenic recessive condition of motile cilia, primary ciliary dyskinesia (PCD). The effects of allele heterozygosity on motile cilia function are unknown. We used CRISPR-Cas9 genome editing in mice to recreate a human missense variant identified in patients with mild PCD and a second, frameshift null deletion in Dnaaf5. Litters with Dnaaf5 heteroallelic variants showed distinct missense and null gene dosage effects. Homozygosity for the null Dnaaf5 alleles was embryonic lethal. Compound heterozygous animals with the missense and null alleles showed severe disease manifesting as hydrocephalus and early lethality. However, animals homozygous for the missense mutation had improved survival, with partial preserved cilia function and motor assembly observed by ultrastructure analysis. Notably, the same variant alleles exhibited divergent cilia function across different multiciliated tissues. Proteomic analysis of isolated airway cilia from mutant mice revealed reduction in some axonemal regulatory and structural proteins not previously reported in DNAAF5 variants. While transcriptional analysis of mouse and human mutant cells showed increased expression of genes coding for axonemal proteins. Together, these findings suggest allele-specific and tissue-specific molecular requirements for cilia motor assembly that may affect disease phenotypes and clinical trajectory in motile ciliopathies. Brief SummaryA mouse model of human DNAAF5 primary ciliary dyskinesia variants reveals gene dosage effects of mutant alleles and tissue-specific molecular requirements for cilia motor assembly.

cell biology↗

Gaudichaudione H inhibits Herpes Simplex Virus-1 replication by regulating cellular nuclear factor-κB in an interferon-γ-independent manner

The highly prevalent herpes simplex virus type 1 (HSV-1) causes keratoconjunctivitis and encephalitis. Viral DNA polymerase-inhibiting nucleoside analogs (such as acyclovir) are standard treatment agents against HSV infections but are limited by severe drug resistance issues. Thus, new antiviral agents with novel targets are urgently needed. Earlier, we investigated the anti-cancer, anti-inflammatory, and antibacterial bioactivities of Garcinia sp. Here, we report that non-cytotoxic concentrations (< 500 nM) of Gaudichaudione H (GH, isolated from Garcinia oligantha Merr.) potently inhibits HSV-1 replication in vitro without affecting viral entry or attachment. GH inhibits the expression of the viral proteins ICP0, ICP4, and ICP27 without affecting their mRNA levels. In Vero cells, GH enhanced STAT1 and 3 phosphorylation, which occurs downstream to interferon (IFN)-{gamma} activation during viral infections. However, pharmacological/genetic inhibition of IFN-{gamma} failed to suppress the GH-mediated inhibition of HSV-1 replication, indicating that GH exerts antiviral effects independent of IFN. Further mechanistic studies suggest that GH inhibits HSV-1 replication, at least partially by inhibiting cellular NF-{kappa}B activation. Moreover, GH prolonged the survival rate of KOS-infected mice by 25% (n = 5). In conclusion, GH treatment inhibits HSV-1 replication both in vitro and in vivo; therefore, it can be developed as an antiviral. ImportanceVery few therapeutic drug options are available to treat herpes simplex virus-1/2 which cause myriad debilitating diseases. We screened eight Garcinia compounds and found Gaudichaudione H was the most effective compound at non-cytotoxic concentrations. Further mechanism study illustrates that GH inhibits HSV-1 replication, at least partially by inhibiting cellular NF-{kappa}B activation. Natural compound is a promising resource of new antiviral agents with different targets that has ability to treat resistant viral strains.

cell biology↗

Molecular insights into the gating mechanisms of voltage-gated calcium channel CaV2.3

High-voltage-activated R-type CaV2.3 channel plays pivotal roles in many physiological activities and is implicated in epilepsy, convulsions, and other neurodevelopmental impairments. Here, we determine the high-resolution cryo-electron microscopy (cryo-EM) structure of human CaV2.3 in complex with the 2{delta}1 and {beta}1 subunits. The VSDII is stabilized in the resting state. Electrophysiological experiments elucidate that the conformational change of VSDII in response to variation in membrane potential is not required for channel activation, whereas the other VSDs are essential for channel opening. The intracellular gate is blocked by the W-helix. A pre-W-helix adjacent to the W-helix can significantly regulate closed-state inactivation (CSI) by modulating the association and dissociation of the W-helix with the gate. Electrostatic interactions formed between the negatively charged domain on S6II, which is exclusively conserved in the CaV2 family, and nearby regions at the alpha-interacting domain (AID) and S4-S5II helix are identified. Further functional analyses indicate that these interactions are critical for the open-state inactivation (OSI) of CaV2 channels.

biophysics↗

Targeting TR4-induced RCC cells-derived exosomally initiated signaling increases Sunitinib efficacy

Sunitinib is the first-line therapy for metastatic clear cell renal cell carcinoma (RCC) via suppressing neoangiogenesis and tumor growth. The detailed mechanisms, especially whether and how RCC cells can impact endothelial cells sensitivity to Sunitinib, remain unclear. Here, we found that TR4 was commonly upregulated in RCC tissue and relative to tumor angiogenesis. Tube formation and Mouse aortic ring assay showed that the overexpression or knockdown of TR4 in RCC cells enhanced or reduced the angiogenesis of endothelial cells and their resistance to Sunitinib in vitro. Mechanistically, We found that TR4 transcriptionally increase ADAM15 expression, as a consequence, exosomes carrying relatively large amounts of ADAM15 secreted from RCC cell resulted in activating the EGFR phosphorylation and reducing the efficacy of Sunitinib in endothelial cells. Targeting the TR4-induced renal cancers-derived exosomelly initiated signaling with a small molecular, CRM197, increases sunitinib efficacy in vitro and xenograft tumor models. Taken together, our findings indicate a novel function of TR4 in RCC blunted the efficacy of sunitinib via exosomal ADAM15-induced activation of EGFR signaling pathway in endothelial cells.

cancer biology↗

Generate a new crucian carp (Carassius auratus) strain without intermuscular bones by knocking out bmp6

Elimination of intermuscular bones (IMBs) is vital to the aquaculture industry of cyprinids. In our previous study, we characterized bmp6 as essential in the development of IMBs in zebrafish. Knockout of bmp6 results in the absence of IMBs in zebrafish without affecting growth and reproduction. Therefore, we hypothesized that bmp6 could be used to generate new cyprinid strains without IMBs by gene editing. In this study, we established a gene editing strategy for knocking out the two orthologs of bmp6 in diploid crucian carp (Carassius auratus). We obtained an F3 population with both orthologs knocked out, in which no IMBs were detected by bone staining and X-ray, indicating that the new strain without IMBs (named WUCI strain) was successfully generated. Furthermore, we extensively evaluated the performance of the new strain in growth, reproduction, nutrient components, muscle texture and structure, and metabolites in muscle. The results showed that the WUCI strain grew faster than the wild-type crucian carp at 4-month-age. The reproductive performance and flesh quality did not show significant differences between the WUCI strain and wild-type crucian carp. Moreover, the metabolomics analysis suggested that the muscle tissues of the WUCI strain significantly enriched some metabolites belonging to the Thiamine metabolism, Nicotinate and Nicotinamide Metabolism pathway, which plays beneficial effects in anti-aging, anti-oxidant, and anti-radiation damage. In conclusion, we established a strategy to eliminate IMBs in crucian carp and obtain a WUCI strain whose performance was expected compared to the wild-type crucian carp; meanwhile, the WUCI strain enriched some beneficial metabolites to human health in muscle tissue. This study is the first report that a farmed cyprinid strain without IMBs, which could be stably inherited, was obtained worldwide; it provided excellent germplasm for the cyprinids aquaculture industry and a useful molecular tool for eliminating IMBs in other cyprinids.

genetics↗

Pisces: A combo-wise contrastive learning approach to synergistic drug combination prediction

Drug combination therapy is promising for cancer treatment through simultaneously reducing resistance and improving efficacy. Machine learning approaches to drug combination response prediction can prioritize experiments and discover new combinations, but require lots of training data in order to fit the nonlinearity of synergistic effect. Here, we propose Pisces, a novel machine learning approach for drug combination synergy prediction. The key idea of Pisces is to augment the sparse drug combination dataset by creating multiple views for each drug combination based on its different modalities. We combined eight different modalities of a single drug to create 64 augmented views for a pair of drugs, effectively expanding the size of the original data 64 times. Pisces obtained state-of-the-art results on cell-line-based drug synergy prediction, xenograft-based drug synergy prediction, and drug-drug interaction prediction. By interpreting Piscess predictions using a genetic interaction network, we further identified a breast cancer drug-sensitive pathway from BRCA cell lines in GDSC. We validated this pathway on an independent TCGA-BRCA tumor dataset and found that patients with this pathway activated had substantially longer survival time. Collectively, Pisces effectively predicts drug synergy and drug-drug interactions through augmenting the original dataset 64 times, and can be broadly applied to various biological applications that involve a pair of drugs.

molecular biology↗