Biology subjects

Chen, M.

Publications and source records attributed to Chen, M..

At least 433 records · Page 24Linked to original sources

bioRxiv2021

Tapping into non-English-language science for the conservation of global biodiversity

The widely held assumption that any important scientific information would be available in English underlies the underuse of non-English-language science across disciplines. However, non-English-language science is expected to bring unique and valuable scientific information, especially in disciplines where the evidence is patchy, and for emergent issues where synthesising available evidence is an urgent challenge. Yet such contribution of non-English-language science to scientific communities and the application of science is rarely quantified. Here we show that non-English-language studies provide crucial evidence for informing global biodiversity conservation. By screening 419,680 peer-reviewed papers in 16 languages, we identified 1,234 non-English-language studies providing evidence on the effectiveness of biodiversity conservation interventions, compared to 4,412 English-language studies identified with the same criteria. Relevant non-English-language studies are being published at an increasing rate, and can expand the geographical (by 12-25%) and taxonomic (by 5-32%) coverage of English-language evidence, especially in biodiverse regions, albeit often based on less robust study designs. Our results show that synthesising non-English-language studies is key to overcoming the widespread lack of local, context-dependent evidence and facilitating evidence-based conservation globally. We urge wider disciplines to rigorously reassess the untapped potential of non-English-language science in informing decisions to address other global challenges.

scientific communication and education↗

bioRxiv2021

Cryo-ET reveals two major tubulin-based cytoskeleton structures in Toxoplasma gondii

In the obligate intracellular parasite, Toxoplasma gondii, the subpellicular microtubules (SPMTs) help maintain shape, while the apical conoid (also tubulin-based) is implicated in invasion. Here, we use cryo-electron tomography to determine the molecular structures of the SPMTs and the conoid-fibrils (CFs) in vitrified and detergent-lysed parasites. Subvolume densities from detergent-extracted parasites yielded averaged density maps at subnanometer resolutions, and these were related back to their architecture in situ. An intraluminal spiral (IS) lines the interior of the 13-protofilament SPMTs, revealing a preferred orientation of these microtubules relative to the parasites long axis. Each CF is composed of 9 tubulin protofilaments, that produce a comma-shaped cross-section, plus additional associated components. Conoid protrusion, a crucial step in invasion, is associated with an altered pitch of each CF. The use of basic building blocks of protofilaments and different accessory proteins in one organism, illustrates the versatility of these critical structures.

molecular biology↗

bioRxiv2021

Broad neutralization against SARS-CoV-2 variants induced by a modified B.1.351 protein-based COVID-19 vaccine candidate

Beginning in late 2020, the emergence and spread of multiple variant SARS-CoV-2 strains harboring mutations which may enable immune escape necessitates the rapid evaluation of second generation COVID-19 vaccines, with the goal of inducing optimized immune responses that are broadly protective. Here we demonstrate in a mouse immunogenicity study that two doses of a modified B.1.351 spike (S)-Trimer vaccine (B.1.351 S-Trimer) candidate can induce strong humoral immune responses that can broadly neutralize both the original SARS-CoV-2 strain (Wuhan-Hu-1) and Variants of Concern (VOCs), including the UK variant (B.1.1.7), South African variant (B.1.351) and Brazil variant (P.1). Furthermore, while immunization with two doses (prime-boost) of Prototype S-Trimer vaccine (based on the original SARS-CoV-2 strain) induced lower levels of cross-reactive neutralization against the B.1.351 variant, a third dose (booster) administered with either Prototype S-Trimer or B.1.351 S-Trimer was able to increase neutralizing antibody titers against B.1.351 to levels comparable to neutralizing antibody titers against the original strain elicited by two doses of Prototype S-Trimer.

immunology↗

bioRxiv2021

Synergism between Chromatin Dynamics and Gene Transcription Enhances Robustness and Stability of Epigenetic Cell Memory

Apart from carrying hereditary information inherited from their ancestors and being able to pass on the information to their descendants, cells can also inherit and transmit information that is not stored as changes in their genome sequence. Such epigenetic cell memory, which is particularly important in multicellular organisms, involves multiple biochemical modules mainly including chromatin organization, epigenetic modification and gene transcription. The synergetic mechanism among these three modules remains poorly understood and how they collaboratively affect the robustness and stability of epigenetic memory is unclear either. Here we developed a multiscale model to address these questions. We found that the chromatin organization driven by long-range epigenetic modifications can significantly enhance epigenetic cell memory and its stability in contrast to that driven by local interaction and that chromatin topology and gene activity can promptly and simultaneously respond to changes in nucleosome modifications while maintaining the robustness and stability of epigenetic cell memory over several cell cycles. We concluded that the synergism between chromatin dynamics and gene transcription facilitates the faithful inheritance of epigenetic cell memory across generations.

systems biology↗

bioRxiv2021

Direct photoresponsive inhibition of a p53-like transcription activation domain in PIF3 by Arabidopsis phytochrome B

Phytochrome B (PHYB) triggers diverse light responses in Arabidopsis by binding to a group of antagonistically acting PHYTOCHROME-INTERACTING transcription FACTORs (PIFs) to promote PIF degradation, consequently downregulating PIF target genes. However, whether PHYB directly controls the transactivation activity of PIFs remains ambiguous. Here we show that the prototypic PIF, PIF3, possesses a p53-like transcription activation domain (TAD) consisting of a sequence-specific, hydrophobic activator motif surrounded by acidic residues. A PIF3mTAD mutant in which the activator motif is replaced with alanines fails to activate PIF3 target genes in Arabidopsis in dark, light, and shade conditions, validating the in vivo functions of the PIF3 TAD. Intriguingly, binding of PHYBs N-terminal photosensory module to the PHYB-binding site adjacent to the TAD inhibits its transactivation activity. These results unveil a photoresponsive transcriptional switching mechanism in which photoactivated PHYB directly masks the transactivation activity of PIF3. Our study also suggests the unexpected conservation of sequence-specific TADs between the animal and plant kingdoms.

plant biology↗

bioRxiv2021

Molecular architecture of black widow spider neurotoxins

Latrotoxins (LaTXs) are presynaptic pore-forming neurotoxins found in the venom of Latrodectus spiders. The venom contains a toxic cocktail of seven LaTXs, with one of them targeting vertebrates (-latrotoxin (-LTX)), five specialized on insects (, {beta}, {gamma}, {delta}, {varepsilon}-latroinsectotoxins (LITs), and one on crustaceans (-latrocrustatoxin (-LCT)). LaTXs bind to specific receptors on the surface of neuronal cells, inducing the release of neurotransmitters either by directly stimulating exocytosis or by forming Ca2+-conductive tetrameric pores in the membrane. Despite extensive studies in the past decades, a high-resolution structure of a LaTX is not yet available and the precise mechanism of LaTX action remains unclear. Here, we report cryoEM structures of the -LCT monomer and the {delta}-LIT dimer. The structures reveal that LaTXs are organized in four domains. A C-terminal domain of ankyrin-like repeats shields a central membrane insertion domain of six parallel -helices. Both domains are flexibly linked via an N-terminal -helical domain and a small {beta}-sheet domain. A comparison between the structures suggests that oligomerization involves major conformational changes in LaTXs with longer C-terminal domains. Based on our data we propose a cyclic mechanism of oligomerization, taking place prior membrane insertion. Both recombinant -LCT and {delta}-LIT form channels in artificial membrane bilayers, that are stabilized by Ca2+ ions and allow calcium flux at negative membrane potentials. Our comparative analysis between -LCT and {delta}-LIT provides first crucial insights towards understanding the molecular mechanism of the LaTX family.

biophysics↗

bioRxiv2021

Isolation, screening, degradation characteristics of a quinclorac-degrading bacteria D and its potential of bioremediation for rice field environment polluted by quinclorac

Quinclorac (QNC) is a highly selective, hormonal, and low-toxic herbicide with a long duration. And the growth and development of subsequent crops are easily affected by QNC accumulated in the soil. In this paper, a QNC-degrading strain D was isolated and screened from the rice paddy soil. Through morphology, physiological and biochemical tests and 16Sr DNA gene analysis, strain D was identified as Cellulosimicrobium cellulans sp. And the QNC degradation characteristics of strain D were studied. Under the optimal culture conditions, the QNC-degrading rate was 45.9% after culturing for 21 days. The QNC-degrading efficiency of strain D in the field was evaluated by a simulated pot experiment. The results show that strain D can promote the growth of rice and QNC-degrading effectively. This research could provide a new bacterial species for microbial degradation of QNC and lay a theoretical foundation for further research on QNC remediation. ImportanceAt present, some QNC-degrading bacteria have been isolated from different environments, but there are no reports of Cellulosimicrobium cellulans sp. bacterial that could degrade QNC. In this study, a new QNC-degradation strain was selected from the paddy soil. The degradation characteristics of strain D were studied in detail. The results shown that strain D had a satisfactory quinclorac-degrading efficiency. Two degradation products of QNC by strain D were identified by HPLC-Q-TOF/MS: 3-pyridylacetic acid (138.0548 m/z) and 3-ethylpyridine (108.0805 m/z), which have not been reported before. The strain D had a potential ability of quinclorac-degrading effectively in the quinclorac-polluted paddy field environment.

microbiology↗

bioRxiv2021

Fast slow folding of an Outer Membrane Porin

In comparison to globular proteins, the spontaneous folding and insertion of {beta}-barrel membrane proteins is surprisingly slow, typically occurring on the order of minutes. Using single-molecule Forster Resonance Energy Transfer to report on the folding of fluorescently-labelled Outer Membrane Protein G we measured the real-time insertion of a {beta}-barrel membrane protein from an unfolded state. Folding events were rare, and fast (<20 ms); occurring immediately upon arrival at the membrane. This combination of infrequent, but rare, folding resolves this apparent dichotomy between slow ensemble kinetics, and the typical timescales of biomolecular folding.

biophysics↗

bioRxiv2021

Development of a mini-replicon-based reverse-genetics system for rice stripe tenuivirus

Negative-stranded RNA (NSR) viruses include both animal- and plant-infecting viruses that often cause serious diseases in human and livestock, and in agronomic crops. Rice stripe tenuivirus (RSV), a plant NSR virus with four negative-stranded/ambisense RNA segments, is one of the most destructive rice pathogens in many Asian countries. Due to the lack of a reliable reverse-genetics technology, molecular studies of RSV gene functions and its interaction with host plants are severely hampered. To overcome this obstacle, we developed a mini-replicon-based reverse-genetics system for RSV gene functional analysis in Nicotiana benthamiana. We first developed a mini-replicon system expressing RSV genomic RNA3 eGFP reporter (MR3(-)eGFP), a nucleocapsid (NP), and a codon usage optimized RNA-dependent RNA polymerase (RdRpopt), respectively. Using this mini-replicon system we determined that RSV NP and RdRpopt are indispensable for the eGFP expression from MR3(-)eGFP. The expression of eGFP from MR3(-)eGFP can be significantly enhanced in the presence of NSs and P19-HcPro-{gamma}b. In addition, NSvc4, the movement protein of RSV, facilitated eGFP trafficking between cells. We also developed an antigenomic RNA3-based replicon in N. benthamiana. However, we found that the RSV NS3 coding sequence acts as a cis-element to regulate viral RNA expression. Finally, we made mini-replicons representing all four RSV genomic RNAs. This is the first mini-replicon-based reverse-genetics system for monocot-infecting tenuivirus. We believe that this mini-replicon system described here will allow the studies of RSV replication, transcription, cell-to-cell movement and host machinery underpinning RSV infection in plants. IMPORTANCEPlant-infecting segmented negative-stranded RNA (NSR) viruses are grouped into 3 genera: Orthotospovirus, Tenuivirus and Emaravirus. The reverse-genetics systems have been established for members in the genera Orthotospovirus and Emaravirus, respectively. However, there is still no reverse-genetics system available for Tenuivirus. Rice stripe virus (RSV) is a monocot-infecting tenuivirus with four negative-stranded/ambisense RNA segments. It is one of the most destructive rice pathogens and causes significant damages to rice industry in Asian countries. Due to the lack of a reliable reverse-genetics system, molecular characterizations of RSV gene functions and the host machinery underpinning RSV infection in plants are extremely difficult. To overcome this obstacle, we developed a mini-replicon-based reverse-genetics system for RSV in Nicotiana benthamiana. This is the first mini-replicon-based reverse-genetics system for tenuivirus. We consider that this system will provide researchers a new working platform to elucidate the molecular mechanisms dictating segmented tenuivirus infections in plant.

pathology↗

bioRxiv2021

PRMT5 regulates ovarian follicle development by facilitating Wt1 translation

Protein arginine methyltransferase 5 (Prmt5) is the major type II enzyme responsible for symmetric dimethylation of arginine. Here, we found PRMT5 was expressed at high level in ovarian granulosa cells of growing follicles. Inactivation of Prmt5 in granulosa cells resulted in aberrant follicle development and female infertility. In Prmt5-knockout mice, follicle development was arrested with disorganized granulosa cells in which WT1 expression was dramatically reduced and the expression of steroidogenesis-related genes was significantly increased. The premature differentiated granulosa cells were detached from oocytes and follicle structure was disrupted. Mechanism studies revealed that Wt1 expression was regulated by PRMT5 at the protein level. PRMT5 facilitated IRES-dependent translation of Wt1 mRNA by methylating HnRNPA1. Moreover, the upregulation of steroidogenic genes in Prmt5-deficient granulosa cells was repressed by Wt1 overexpression. These results demonstrate PRMT5 participates in granulosa cell lineage maintenance by inducing Wt1 expression. Our study uncovers a new role of post-translational arginine methylation in granulosa cell differentiation and follicle development.

developmental biology↗

bioRxiv2021

Comparative genomics reveals evolutionary drivers of sessile life and left-right shell asymmetry in bivalves

Bivalves are species-rich mollusks with prominent protective roles in coastal ecosystems. Across these ancient lineages, colony-founding larvae anchor themselves either by byssus production or by cemented attachment. The latter mode of sessile life is strongly molded by left-right shell asymmetry during larval development of Ostreoida oysters such as Crassostrea hongkongensis. Here, we sequenced the genome of C. hongkongensis in high resolution and compared it to reference bivalve genomes to unveil genomic determinants driving cemented attachment and shell asymmetry. Importantly, loss of the homeobox gene antennapedia (Antp) and broad expansion of lineage-specific extracellular gene families are implicated in a shift from byssal to cemented attachment in bivalves. Evidence from comparative transcriptomics shows that the left-right asymmetrical C. hongkongensis plausibly diverged from the symmetrical Pinctada fucata in expression profiles marked by elevated activities of orthologous transcription factors and lineage-specific shell-related gene families including tyrosinases, which may cooperatively govern asymmetrical shell formation in Ostreoida oysters.

genomics↗

bioRxiv2021

Neural Basis of the Delayed Gratification

Balancing instant gratification versus delayed, but better gratification is important for optimizing survival and reproductive success. Although psychologists and neuroscientists have long attempted to study delayed gratification through human psychological and brain activity monitoring, and animal research, little is known about its neural basis. We successfully trained mice to perform a waiting-and-water-reward delayed gratification task and used these animals in physiological recording and optical manipulation of neuronal activity during the task to explore its neural basis. Our results showed that the activity of DA neurons in ventral tegmental area (VTA) increases steadily during the waiting period. Optical activation vs. silencing of these neurons, respectively, extends or reduces the duration of waiting. To interpret this data, we developed a reinforcement learning (RL) model that reproduces our experimental observations. In this model, steady increases in DAergic activity signal the value of waiting and support the hypothesis that delayed gratification involves real-time deliberation. TEASERSustained ramping dopaminergic activation helps individuals to resist impulsivity and wait for laerger but later return.

neuroscience↗

bioRxiv2021

A mouse model of occult intestinal colonization demonstrating antibiotic-induced outgrowth of carbapenem-resistant Enterobacteriaceae

BackgroundThe human intestinal microbiome is a complex community that contributes to host health and disease. In addition to normal microbiota, pathogens like carbapenem-resistant Enterobacteriaceae may be asymptomatically present. When these bacteria are present at very low levels, they are often undetectable in hospital surveillance cultures, known as occult or subclinical colonization. Through the use of antibiotics, these subclinical pathogens can increase to sufficiently high levels to become detectable, in a process called outgrowth. However, little is known about the interaction between gut microbiota and Enterobacteriaceae during occult colonization and outgrowth. ResultsWe developed a clinically relevant mouse model for studying occult colonization. Conventional wild-type mice without antibiotic pre-treatment were exposed to K. pneumoniae but rapidly tested negative for colonization. This occult colonization was found to perturb the microbiome as detected by both 16S rRNA amplicon and shotgun metagenomic sequencing. Outgrowth of occult K. pneumoniae was induced either by a four-antibiotic cocktail or by individual receipt of ampicillin, vancomycin or azithromycin, which all reduced overall microbial diversity. Notably, vancomycin was shown to trigger K. pneumoniae outgrowth in only a subset of exposed animals (outgrowth-susceptible). To identify factors that underlie outgrowth susceptibility, we analyzed microbiome-encoded gene functions and were able to classify outgrowth-susceptible microbiomes using pathways associated with mRNA stability. Lastly, an evolutionary approach illuminated the importance of xylose metabolism in K. pneumoniae colonization, supporting xylose abundance as a second susceptibility indicator. We showed that our model is generalizable to other pathogens, including carbapenem-resistant Escherichia coli and Enterobacter cloacae. ConclusionsThis study suggests that microbiota mRNA and small-molecule metabolites may be used to predict outgrowth-susceptibility. Our modeling of occult colonization and outgrowth could help the development of strategies to mitigate the risk of subsequent infection and transmission in medical facilities and the wider community.

microbiology↗

bioRxiv2021

Genome Warehouse: A Public Repository Housing Genome-scale Data

The Genome Warehouse (GWH) is a public repository housing genome assembly data for a wide range of species and delivering a series of web services for genome data submission, storage, release, and sharing. As one of the core resources in the National Genomics Data Center (NGDC), part of the China National Center for Bioinformation (CNCB, https://bigd.big.ac.cn/), GWH accepts both full genome and partial genome (chloroplast, mitochondrion, and plasmid) sequences with different assembly levels, as well as an update of existing genome assemblies. For each assembly, GWH collects detailed genome-related metadata including biological project and sample, and genome assembly information, in addition to genome sequence and annotation. To archive high-quality genome sequences and annotations, GWH is equipped with a uniform and standardized procedure for quality control. Besides basic browse and search functionalities, all released genome sequences and annotations can be visualized with JBrowse. By December 2020, GWH has received 17,264 direct submissions covering a diversity of 949 species, and has released 3370 of them. Collectively, GWH serves as an important resource for genome-scale data management and provides free and publicly accessible data to support research activities throughout the world. GWH is publicly accessible at https://bigd.big.ac.cn/gwh/.

bioinformatics↗

bioRxiv2021

Nanotraps for the containment and clearance of SARS-CoV-2

SARS-CoV-2 enters host cells through its viral spike protein binding to angiotensin-converting enzyme 2 (ACE2) receptors on the host cells. Here we show functionalized nanoparticles, termed "Nanotraps", completely inhibited SARS-CoV-2 infection by blocking the interaction between the spike protein of SARS-CoV-2 and the ACE2 of host cells. The liposomal-based Nanotrap surfaces were functionalized with either recombinant ACE2 proteins or anti-SARS-CoV-2 neutralizing antibodies and phagocytosis-specific phosphatidylserines. The Nanotraps effectively captured SARS-CoV-2 and completely blocked SARS-CoV-2 infection to ACE2-expressing human cell lines and primary lung cells; the phosphatidylserine triggered subsequent phagocytosis of the virus-bound, biodegradable Nanotraps by macrophages, leading to the clearance of pseudotyped and authentic virus in vitro. Furthermore, the Nanotraps demonstrated excellent biosafety profile in vitro and in vivo. Finally, the Nanotraps inhibited pseudotyped SARS-CoV-2 infection in live human lungs in an ex vivo lung perfusion system. In summary, Nanotraps represent a new nanomedicine for the inhibition of SARS-CoV-2 infection. HighlightsO_LINanotraps block interaction between SARS-CoV-2 spike protein and host ACE2 receptors C_LIO_LINanotraps trigger macrophages to engulf and clear virus without becoming infected C_LIO_LINanotraps showed excellent biosafety profiles in vitro and in vivo C_LIO_LINanotraps blocked infection to living human lungs in ex vivo lung perfusion system C_LI Progress and PotentialTo address the global challenge of creating treatments for SARS-CoV-2 infection, we devised a nanomedicine termed "Nanotraps" that can completely capture and eliminate the SARS-CoV-2 virus. The Nanotraps integrate protein engineering, immunology, and nanotechnology and are effective, biocompatible, safe, stable, feasible for mass production. The Nanotraps have the potential to be formulated into a nasal spray or inhaler for easy administration and direct delivery to the respiratory system, or as an oral or ocular liquid, or subcutaneous, intramuscular or intravenous injection to target different sites of SARS-CoV-2 exposure, thus offering flexibility in administration and treatment. More broadly, the highly versatile Nanotrap platform could be further developed into new vaccines and therapeutics against a broad range of diseases in infection, autoimmunity and cancer, by incorporating with different small molecule drugs, RNA, DNA, peptides, recombinant proteins, and antibodies.

bioengineering↗

bioRxiv2021

PIKfyve inhibition blocks endolysosomal escape of α-synuclein fibrils and spread of α-synuclein aggregation

The inter-cellular prion-like propagation of -synuclein aggregation is emerging as an important mechanism driving the progression of neurodegenerative diseases including Parkinsons disease and multiple system atrophy (MSA). To discover therapeutic strategies reducing the spread of -synuclein aggregation, we performed a genome-wide CRISPR interference screen in a human cell-based model. We discovered that inhibiting PIKfyve dramatically reduced -synuclein aggregation induced with both recombinant -synuclein fibrils and fibrils isolated from MSA patient brain. While PIKfyve inhibition did not affect fibril uptake or -synuclein clearance or secretion, it reduced -synuclein trafficking from the early endosome to the lysosome, thereby limiting fibril escape from the lysosome and reducing the amount of fibrils that reach cytosolic -synuclein to induce aggregation. These findings point to the endolysosomal transport of fibrils as a critical step in the propagation of -synuclein aggregation and a potential therapeutic target.

cell biology↗

bioRxiv2021

BRD2 inhibition blocks SARS-CoV-2 infection in vitro by reducing transcription of the host cell receptor ACE2

SARS-CoV-2 infection of human cells is initiated by the binding of the viral Spike protein to its cell-surface receptor ACE2. We conducted a targeted CRISPRi screen to uncover druggable pathways controlling Spike protein binding to human cells. We found that the protein BRD2 is required for ACE2 transcription in human lung epithelial cells and cardiomyocytes, and BRD2 inhibitors currently evaluated in clinical trials potently block endogenous ACE2 expression and SARS-CoV-2 infection of human cells, including those of human nasal epithelia. Moreover, pharmacological BRD2 inhibition with the drug ABBV-744 inhibited SARS-CoV-2 replication in Syrian hamsters. We also found that BRD2 controls transcription of several other genes induced upon SARS-CoV-2 infection, including the interferon response, which in turn regulates the antiviral response. Together, our results pinpoint BRD2 as a potent and essential regulator of the host response to SARS-CoV-2 infection and highlight the potential of BRD2 as a novel therapeutic target for COVID-19.

cell biology↗

bioRxiv2021

Functional differences drive the selection of NRAS mutants in melanoma

Distinct NRAS mutants are enriched in various tumor types. Here, we generated a suite of fully congenic, conditional, Nras knock-in mouse models (LSL-Nras Q61R, -K, -L, -H, -P, -Q; G12D and G13D, -R) to test the hypothesis that melanocyte transformation requires functions specific to the NRAS mutants enriched in human melanoma (Q61R and Q61K). Consistent with the rarity of NRAS codon 12 and 13 mutants in human melanoma, spontaneous melanomas were rare or absent in mice expressing NRAS G12D, G13D or G13R. Mice expressing less common codon 61 alleles (Q61H, Q61P) also developed few or no tumors. NRAS Q61R, Q61K, or Q61L expression, by contrast, induced rapid melanoma onset with high penetrance. Cohorts of heterozygous mice containing one LSL-Nras Q61R and one LSL-Nras Q61K, -L, -H, -P, or -Q allele were generated to assess potential interactions between NRAS mutants. The ability of each Nras variant to substitute for an Nras Q61R allele was consistent with its own ability to drive spontaneous melanoma formation. However, LSL-Nras Q61Q/Q61R mice rarely developed tumors. In vitro experiments in mouse embryonic fibroblasts (MEFs) highlighted activation of the MAPK pathway as a defining difference between tumorigenic and non-tumorigenic NRAS mutants. Enhanced MAPK activation was associated with the promotion of BRAF-BRAF and BRAF-CRAF dimers. These results support the development of cancer preventative strategies specific to the properties of the commonly observed RAS mutants in each tumor type.

cancer biology↗