Biology subjects

Chang, P.

Publications and source records attributed to Chang, P..

At least 19 recordsLinked to original sources

bioRxiv2026

Spontaneous behavior predicts colony membership, individual identity, and rank in naked mole-rat societies

Animal societies are organized across scales, from moment-to-moment actions of individuals to dynamic group structure. A central challenge in sociobiology is to understand how behaviors of individuals shape group structure. Here, using machine vision to map recurrent fine-scale behavioral modules in the eusocial naked mole-rat (Heterocephalus glaber), we show that spontaneous behavior in isolation predicts group-level social organization, including colony membership and individual identity. We determined dominance relationships and found highly linear hierarchies, with ranks stable over months to years. Remarkably, fine-scale behavioral profiles in isolation correctly predicted pairwise dominance relationships, allowing reconstruction of rank order within each colony. Models trained within one colony predicted rank poorly in others, suggesting that naked mole-rats express social position through behavioral patterns specific to each colony. Together, our results connect fine-scale behavior to social structure maintained over years and show that, even when an animal is alone, its behavior carries signatures of its identity, colony, and place within that society.

animal behavior and cognition↗

bioRxiv2026

Isolation of Zika Virus Replication Complex Reveals a Proviral Nuclear Factor

Zika virus (ZIKV) is an arthropod-borne flavivirus of international public health impact. ZIKV has a positive-sense, single-stranded RNA genome and remodels intracellular membranes to form replication complexes (RCs). The objective of this study was to isolate and characterize the RCs from ZIKV-infected cells and to identify host-cell components recruited to participate in viral replication. Here, we isolated the RCs from ZIKV-infected Vero cells by detergent treatment and flotation centrifugation. Fractional flotation analysis demonstrated that ZIKV proteins NS2B, NS3, and NS5, and ZIKV RNA were present in the detergent-resistant membranous fraction. In contrast, the ER-resident protein calnexin and a mitochondrial protein were present in the detergent-soluble fractions. The isolated RCs were functional for ZIKV RNA synthesis, as shown by quantitative PCR. To determine the components of the RCs, we conducted mass spectrometry analysis and identified numerous cellular proteins. Among them is the replication factor C subunit 2 (RFC2), an accessory protein of DNA polymerase. RFC2 is involved in ATP binding and hydrolysis and may promote cell survival. ZIKV infection increased the RFC2 protein level and induced its relocation to the cytoplasm. RNAi-mediated silencing of RFC2 reduced ZIKV replication. Together, our results provide insights into ZIKV replication and virus-cell interaction. IMPORTANCEBy isolating and characterizing the ZIKV replication complexes (RCs) from infected Vero cells, this research provides valuable insights into the viruss strategy for hijacking host intracellular membranes and proteins. The identification of ZIKV proteins (NS2B, NS3, and NS5) and RNA in detergent-resistant, lipid-rich membranous structures and the confirmation of functional RCs in RNA synthesis demonstrate successful RC purification. Mass spectrometry and proteomic analysis of the RCs identified numerous cellular proteins that may contribute to ZIKV RC formation and RNA synthesis. Notably, among them is the replication factor C subunit 2 (RFC2), an accessory protein of DNA polymerase in the nucleus. Our results demonstrate that ZIKV increases the level of RFC2 and relocates it to the cytoplasm and that RFC2 plays a role in ZIKV replication, as its depletion reduces viral yield. These results provide insights into ZIKV-cell interactions and potentially facilitate future development of novel antiviral strategies.

microbiology↗

bioRxiv2026

Inducible lipid storage and steatosis in the human choroid plexus associated with age and adiposity

Cells that store lipids for other cells or organs can contain "giant" or large lipid droplets (LLDs) greater than 2 {micro}m in diameter. In this study, human postmortem choroid plexus was evaluated for lipid droplets. Staining with hematoxylin and eosin (H&E), the lipophilic dye Oil red O, and anti-adipophilin antibodies established the presence of LLDs exceeding 10 {micro}m in diameter in choroid plexus epithelial cells (CPECs). Manual annotation of H&E stains from 105 cases revealed a significant association between age and the percentage of CPECs containing LLDs (reaching up to 69%) and involving LLDs in our largest annotated category (>5 {micro}m in diameter). The LLD association with age was replicated and extended to a total of 245 cases using a trained convolutional neural network, which further showed significant associations with body mass index at time of death (increasing with BMI), sex (higher in females >65 years old), and a near-significant association with Alzheimers Disease (lower in AD). Like HepG2 and derived hepatocytes, excess fatty acids in culture media readily induced LLDs and steatosis in human embryonic stem cell-derived CPECs. Akin to hepatocytes for the human body, we propose that CPECs store lipids for the human brain and become steatotic in the setting of excess adiposity.

pathology↗

bioRxiv2025

Mapping Haemagglutinin Residues Driving Antigenic Diversity in H5Nx Avian Influenza Viruses

Since its emergence in 1996, the H5 avian influenza virus (AIV) A/Goose/Guangdong/1/1996 (Gs/GD) haemagglutinin (HA) has evolved into over 30 genetically and antigenically distinct clades, including the widespread clade 2.3.4.4b. Vaccination is widely used in endemic regions to reduce poultry losses and zoonotic risk. However, the evolving antigenic diversity and global co-circulation of multiple clades challenges protective efficacy of poultry vaccines with poor antigenic matching to field strains, resulting in immune escape and vaccine failure. This study aimed to improve vaccine seed selection by identifying HA epitopes contributing to inter-clade antigenic differences. Recombinant clade-representative viruses were generated using HA genes from circulating H5 AIVs via reverse genetics with A/Puerto Rico/8/1934 (PR8) internal and neuraminidase genes. Antigenic relationships were assessed using haemagglutination inhibition (HI) assays with homologous and heterologous chicken antisera. Antigenic cartography revealed a clear distinction of clade 2.3.4.4 from others and notable intra-clade diversity. Pairwise antigenic and genetic comparisons identified 48 putative antigenic residues. These were individually introduced into a candidate HA by site-directed mutagenesis, and antigenic influence assessed by HI using sera raised against the non-mutated HA. Four residues R82K, A83T, T204I, and F229Y had significant antigenic effects, with three (R82K, T204I, F229Y) being novel. These findings demonstrate that combining serology and in silico residue analysis can identify key antigenic determinants. This work highlights the need for precise antigenic matching in vaccine design and highlights the value of combining molecular and immunological tools to optimise vaccine seed selection against diverse and evolving H5 AIV strains. ImportanceThe continued evolution of H5 avian influenza viruses (AIVs), particularly the Gs/GD lineage, poses major challenges for poultry disease control and zoonotic risk mitigation. Vaccine effectiveness is undermined by antigenic drift and the co-circulation of diverse clades, often leading to mismatches between vaccine and field strains. This study addresses the critical need to improve vaccine strain selection by identifying haemagglutinin (HA) residues driving antigenic variation across H5 clades. Using recombinant viruses, antigenic cartography, haemagglutination inhibition (HI) assays, and mutagenesis, 48 putative antigenic residues were identified, with four R82K, A83T, T204I, and F229Y having major antigenic effects, three of which were novel. These findings advance our understanding of H5 antigenic evolution and provide a framework for predicting vaccine performance. By integrating molecular and serological data, our work informs rational vaccine seed strain selection, contributing to more broadly protective vaccines and improved control of H5 AIV in poultry, while reducing the risk of zoonotic transmission.

immunology↗

bioRxiv2025

TMEDs Mediate Versatile Cargo Transport in Vesicle-dependent Unconventional Secretion

Unconventional protein secretion (UcPS) exports diverse signal peptide-lacking cargoes, yet its cargo selectivity remains poorly understood. Here, we identify TMED proteins as key regulators of vesicle-dependent UcPS, mediating selective cargo release via translocation into secretory carriers. TMED proteins act as translocators, facilitating cargo passage across lipid bilayers with assistance from HSP90 chaperones and partial cargo unfolding. Selectivity arises during translocation, where TMED cytoplasmic tails bind specific cargoes. The ER-Golgi intermediate compartment (ERGIC) is essential for TMED-mediated translocation and release. TMED homo-oligomerization enhances translocation, while hetero-tetramerization inhibits it. ERGIC localization promotes homo-oligomerization, which is further stabilized by cargo binding, forming a feed-forward mechanism to enhance translocation. These findings establish TMED proteins as central regulators of cargo diversity in UcPS, with their oligomerization and subcellular localization modulating translocation efficiency.

cell biology↗

bioRxiv2025

Solubilization of Membrane Proteins using designed protein WRAPS

The development of therapies and vaccines targeting integral membrane proteins has been complicated by their extensive hydrophobic surfaces, which can make production and structural characterization difficult. Here we describe a general deep learning-based design approach for solubilizing native membrane proteins while preserving their sequence, fold, and function using genetically encoded de novo protein WRAPs (Water-soluble RFdiffused Amphipathic Proteins) that surround the lipid-interacting hydrophobic surfaces, rendering them stable and water-soluble without the need for detergents. We design WRAPs for both beta-barrel outer membrane and helical multi-pass transmembrane proteins, and show that the solubilized proteins retain the binding and enzymatic functions of the native targets with enhanced stability. Syphilis vaccine development has been hindered by difficulties in characterizing and producing the outer membrane protein antigens; we generated soluble versions of four Treponema pallidum outer membrane beta barrels which are potential syphilis vaccine antigens. A 4.0 [A] cryo-EM map of WRAPed TP0698 is closely consistent with the design model. WRAPs should be broadly useful for facilitating biochemical and structural characterization of integral membrane proteins, enabling therapeutic discovery by screening against purified soluble targets, and generating antigenically intact immunogens for vaccine development.

biochemistry↗

bioRxiv2025

From Local Interactions to Global Patterns: An Analysis of Silk Density in Spider Webs

This study explores the structural complexity of spider webs through information-theoretic and harmonicity-based frameworks to quantify spatial patterns in silk density across different web regions and reveal the underlying resource allocation strategies. Currently, there is no normalized approach for describing web structure and complexity, particularly for sheet-webs, and this methodology allows for non-destructive scanning and quantification of web characteristics. By analyzing the entropy of silk density distributions, a single scalar that captures the heterogeneity of material investment across the entire web, we observed that the entropy values follow a normal distribution with a mean of 1.24 {+/-} 0.22 bits when using 10 quantization levels. In the second part of the paper, by measuring the harmonicity of the silk density, we reveal that the silk density at a given point can be inferred from its neighbors, with an average harmonicity value of 0.0039 {+/-} 0.0017 (fraction of total points in point cloud data). The harmonic behavior is notable for its maximum principle, suggesting that the strongest parts of the web appear at the boundaries, aligning with existing knowledge of spider web construction. These findings provide a new technique for quantifying web-building strategies and offer new insights into spider behavior and evolution.

animal behavior and cognition↗

bioRxiv2024

Ubiquitin Ligase ITCH Regulates Life Cycle of SARS-CoV-2 Virus

SARS-CoV-2 infection poses a major threat to public health, and understanding the mechanism of viral replication and virion release would help identify therapeutic targets and effective drugs for combating the virus. Herein, we identified E3 ubiquitin-protein ligase Itchy homolog (ITCH) as a central regulator of SARS-CoV-2 at multiple steps and processes. ITCH enhances the ubiquitination of viral envelope and membrane proteins and mutual interactions of structural proteins, thereby aiding in virion assembly. ITCH-mediated ubiquitination also enhances the interaction of viral proteins to the autophagosome receptor p62, promoting their autophagosome-dependent secretion. Additionally, ITCH disrupts the trafficking of the protease furin and the maturation of cathepsin L, thereby suppressing their activities in cleaving and destabilizing the viral spike protein. Furthermore, ITCH exhibits robust activation during the SARS-CoV-2 replication stage, and SARS-CoV-2 replication is significantly decreased by genetic or pharmacological inhibition of ITCH. These findings provide new insights into the mechanisms of the SARS-CoV-2 life cycle and identify a potential target for developing treatments for the virus-related diseases.

molecular biology↗

bioRxiv2024

Global remodeling of ADP-ribosylation by PARP1 suppresses influenza A virus infection

ADP-ribosylation is a highly dynamic and fully reversible post-translational modification performed by poly(ADP-ribose) polymerases (PARPs) that modulates protein function, abundance, localization and turnover. Here we show that influenza A virus infection causes a rapid and dramatic upregulation of global ADP-ribosylation that inhibits viral replication. Mass spectrometry defined for the first time the global ADP-ribosylome during infection, creating an infection-specific profile with almost 4,300 modification sites on [~]1,080 host proteins, as well as over 100 modification sites on viral proteins. Our data indicate that the global increase likely reflects a change in the form of ADP-ribosylation rather than modification of new targets. Functional assays demonstrated that modification of the viral replication machinery antagonizes its activity and further revealed that the anti-viral activity of PARPs and ADP-ribosylation is counteracted by the influenza A virus protein NS1, assigning a new activity to the primary viral antagonist of innate immunity. We identified PARP1 as the enzyme producing the majority of poly(ADP-ribose) present during infection. Influenza A virus replicated faster in cells lacking PARP1, linking PARP1 and ADP-ribosylation to the anti-viral phenotype. Together, these data establish ADP-ribosylation as an anti-viral innate immune-like response to viral infection antagonized by a previously unknown activity of NS1.

microbiology↗

bioRxiv2024

The Haemagglutinin Genes of the UK Clade 2.3.4.4b H5N1 Avian Influenza Viruses from 2020 to 2022 Retain Strong Avian Phenotype

Since 2020, the United Kingdom (UK) has suffered repeated epizootics of clade 2.3.4.4b H5 high pathogenicity avian influenza viruses (HPAIVs) in wild birds and poultry, resulting in substantial economic losses due to enforced statutory control. The rapid evolution of H5 HPAIVs continues to raise concern with heightened zoonotic and pandemic risks. The immunodominant haemagglutinin glycoprotein (HA) is crucial for influenza virus receptor binding and pH-induced fusion of viral and cellular membranes. Mutations in HA are frequent due to polymerase error, immune pressure and host adaptation, resulting in antigenic modulation and/or an expansion of host tropism, respectively, ultimately hindering control strategies. We evaluated a comprehensive panel of H5 viruses representing prevalent genotypes from UK outbreaks spanning 2020 to 2022 for HA functionality. HA genes from each genotype were assessed through receptor binding, pH of fusion, thermostability and HA inhibition assays to evaluate factors contributing to zoonotic potential, stability, and antigenicity. The viruses only bound to avian receptors and exhibited fusion at a pH of 5.8, above the pH range (pH 5.0 to 5.5) associated with efficient human-to-human transmission. Therefore, these H5 viruses have low immediate zoonotic threat. Contemporary H5 viruses were more thermostable and showed antigenic drift compared to the earlier 2017-2018 clade 2.3.4.4b H5N8 viruses, and N236D in HA was identified as a significant antigenic epitope. The findings of this study underscore the evolving nature of the HA of these viruses and highlight the importance of ongoing surveillance and characterisation efforts to identify factors that might contribute to zoonotic risk.

microbiology↗

bioRxiv2024

Molecular basis of the biogenesis of a protein organelle for ethanolamine utilization

Many pathogenic bacteria use proteinaceous ethanolamine-utilization microcompartments (Eut BMCs) to facilitate the catabolism of ethanolamine, an abundant nutrient in the mammalian gut. The ability to metabolize ethanolamine gives pathogens a competitive edge over commensal microbiota which can drive virulence in the inflamed gut. Despite their critical functions, the molecular mechanisms underlying the synthesis of Eut BMCs in bacterial cells remain elusive. Here, we report a systematic study for dissecting the molecular basis underlying Eut BMC assembly in Salmonella. We determined the functions of individual building proteins in the structure and function of Eut BMCs and demonstrated that EutQ plays an essential role in both cargo encapsulation and Eut BMC formation through specific association with the shell and cargo enzymes. Furthermore, our data reveal that Eut proteins can self-assemble to form cargo and shell aggregates independently in vivo, and that the biogenesis of Eut BMCs follows a unique "Shell-first" pathway. Cargo enzymes exhibit dynamic liquid-like organization within the Eut BMC. These discoveries provide mechanistic insights into the structure and assembly of the Eut BMC, which serves as a paradigm for membrane-less organelles. It opens up new possibilities for therapeutic interventions for infectious diseases.

cell biology↗

bioRxiv2024

Uncovering the roles of the scaffolding protein CsoS2 in mediating the assembly and shape of the α-carboxysome shell

Carboxysomes are proteinaceous organelles featuring icosahedral protein shells that enclose the carbon-fixing enzymes, Rubisco, alone with carbonic anhydrase. The intrinsically disordered scaffolding protein CsoS2 plays a vital role in the construction of -carboxysomes through bridging the shell and cargo enzymes. The N-terminal domain of CsoS2 binds Rubisco and facilitates Rubisco packaging within the -carboxysome, whereas the C-terminal domain of CsoS2 (CsoS2-C) anchors to the shell and promotes shell assembly. However, the role of the middle region of CsoS2 (CsoS2-M) has remained elusive. Here, we conducted indepth examinations on the function of CsoS2-M in the assembly of the -carboxysome shell by generating a series of recombinant shell variants in the absence of cargos. Our results reveal that CsoS2-M assists CsoS2-C in the assembly of the -carboxysome shell and plays an important role in shaping the -carboxysome shell through enhancing the association of shell proteins on both the facet-facet interfaces and flat shell facets. Moreover, CsoS2-M is responsible for recruiting the C-terminal truncated isoform of CsoS2, CsoS2A, into -carboxysomes, which is crucial for Rubisco encapsulation and packaging. This study not only deepens our knowledge of how the carboxysome shell is constructed and regulated but also lays the groundwork for engineering and repurposing carboxysome-based nanostructures for diverse biotechnological purposes.

synthetic biology↗

bioRxiv2024

Human transmembrane protein 68 links triacylglycerol synthesis to membrane lipid homeostasis

Transmembrane protein 68 (TMEM68) is a recently identified mammalian triacylglycerol (TAG) synthase with high expression in the brain. How TMEM68 regulates cellular lipid metabolism in concert with other enzymatic pathways remains poorly understood. In this study, we assessed TMEM68 function in neuro- and gliablastoma cells by combining genetic gain- and loss-of-function approaches with lipidomics. We found that TMEM68 promotes TAG synthesis and lipid droplet formation independently of canonical acyl-CoA:diacylglycerol acyltransferase (DGAT) 1 and 2 enzymes and contributes a discrete fraction of basal cellular TAG storage. Notably, TMEM68 overexpression increased storage lipids at the expense of membrane lipids leading to a profound reduction of ether-linked glycerophospholipids (GPLs). Moreover, altered TMEM68 expression levels were associated with diminished prevalence of polyunsaturated GPLs. We conclude that TMEM68, besides its TAG synthesis function, acts as a multifaceted regulator of membrane lipid composition and polyunsaturated fatty acid homeostasis.

biochemistry↗

bioRxiv2024

Behavioral fingerprinting of the naked mole-rat uncovers signatures of eusociality and social touch

The East African naked mole-rat (Heterocephalus glaber) lives in cooperative subterranean colonies and displays a capacity to recognize social novelty, rank, and identity. The sensory cues used for social recognition remain poorly understood, especially because many of their senses are either lost or greatly reduced in comparison to other mammals. Here, we found that naked mole-rats actively touch faces 100% of the time they encounter one another in a tunnel test, followed by milliseconds speed determination of the rank of the other animal. Even in an open arena, naked mole-rats engage in face-to-face touch hundreds of times in a 10-minute social pairing and colonies do so tens of thousands of times over a 24-hour period in their home environment. To demonstrate the prominence of face touch at a molecular level, we show that social housing conditions lead to widespread activation of mechanosensory ion channels, including Piezo2, in neurons that innervate the face, but not the body. Lastly, to determine the ethological relevance of face touch, we reduced its capacity with facial whisker trimming and revealed an apparent inability for animals to recognize colony members. Together, these findings uncover face touch as a prominent social behavior in naked mole-rats that is intimately linked to social recognition.

neuroscience↗

bioRxiv2023

Investigation of H9N2 avian influenza immune escape mutant that lacks haemagglutination activity

H9N2 avian influenza viruses pose a global threat to animal and human health. While vaccination is essential for mitigating disease impact, these viruses evolve to evade vaccine immunity through changes in the haemagglutinin (HA) glycoprotein. In this study, we identified immune escape mutation in an H9N2 virus resulting from pressure exerted by homologous chicken antisera. The immune-escape variant acquired an amino acid substitution, replacing glycine (G) with glutamic acid (E) at position 149 in the HA protein. The G149E mutant virus lost the ability to agglutinate chicken erythrocytes, while still maintaining replication comparable to the wild-type virus in chicken embryos and cells. This led to the hypothesis that the G149E substitution, leading to a shift from a neutral to a negative charge polarity at HA position 149, might be crucial for the optimal interaction between the virus and receptors on erythrocytes. Investigation indicated that agglutination could be restored by substituting E to positively charged amino acids histidine (H), arginine (R) or lysine (K). These findings suggest that the H9N2 virus may be likely acquire the G149E mutation under immune pressure in nature. This mutation poses challenges to vaccination and surveillance efforts as it partially evades immune protection and is not easily detectable by conventional haemagglutination assays. This underscores the intricate interplay between antigenic variation and viral traits, emphasising the critical need for ongoing surveillance and research to effectively mitigate the risks associated with avian influenza H9N2 viruses. IMPORTANCEUnderstanding how avian influenza viruses evolve to persist in nature is crucial for enhancing disease mitigation tools such as vaccines, diagnostics, and risk assessment. In this study, we identified an H9N2 virus antibody escape mutant with G149E mutation in the haemagglutinin that had lost the ability to agglutinate chicken erythrocytes, while retaining infectivity and replication fitness. The lack of haemagglutination activity potentially negatively impacts routine surveillance and commonly used diagnostics such as haemagglutination assay or haemagglutination inhibition assay. Therefore, it is urgent to develop and adopt alternative methods for viral detection. Difficult to detect variants potentially that are not compatible with common surveillance techniques could circulate remain silent while reassort with other influenza viruses, which posing unpredictable risks to animal and human health. This research helps us better understand avian influenza, leading to improved disease control, diagnostics, and risk assessment to protect both animals and humans.

microbiology↗

bioRxiv2023

In search of a unifying theory of white matter aging: tract morphometry-microstructure relationships

While tract-wise differences in volume and microstructure are common targets of investigation in age-related changes in the white matter (WM), there has been relatively little exploration into other attributes of tract morphometry or its relation to microstructure in vivo, and limited understanding on how they jointly inform the interpretation of the WM aging trajectory. This study examines ten WM tracts for tract-wise differences in morphometry (i.e. volume, length, and volume-to-length ratio) and microstructural integrity (i.e. fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity) using diffusion MRI data from the Human Connectome Project in Aging (HCP-A) with the goal of laying the foundation for a unified model of age-related WM microstructure-morphometry trajectories with a special focus on sex differences. Results indicated widely heterogeneous patterns of decline and morphometry-microstructural associations across tracts. Multi-parametric signatures of decline suggest stages or mechanisms of degeneration that differ between sexes. This work highlights the value of integrating microstructural and morphometric measures of WM health instead of observing them separately, suggesting multiple modes of WM degeneration.

neuroscience↗

bioRxiv2023

Distribution and genetic diversity of South Florida Tephrosia shed light on past cultural use

O_LIThe genus Tephrosia (Fabaceae), the hoary peas, contain high levels of rotenone, which has a long history of human use as a fish poison. We examine the distribution of Tephrosia angustissima, in South Florida to clarify patterns of genetic relatedness and shed light on human plant movement before European contact. Several populations of Tephrosia angustissima with a history of taxonomic uncertainty exist in South Florida and the neighboring Caribbean Islands. C_LIO_LITo clarify relationships in this group, and to elucidate the conservation status of populations in Everglades National Park and Big Cypress National Preserve, we used restriction site associated DNA sequencing (RAD-SEQ) on 94 samples from South Florida and three locations in southwest Puerto Rico. C_LIO_LIAnalysis of variation in SNP markers by the Bayesian STRUCTURE algorithm and principal coordinate analysis both separated the samples into three groups. These three groups were likely separate colonization events of Florida. Genetic diversity is moderate in all of the groups, with only limited evidence of a bottleneck in some of the disjunct South Florida populations. C_LIO_LIOverall, the human association of this group is consistent with a history of human use, suggesting conservation efforts for these taxa should consider their pre-Columbian human associations. C_LI Societal impact statementA great many endangered plant taxa exhibit patterns of edaphic specialization, occurring on particular substrates such as karst or serpentine soils. Human activities, such as the construction of shell middens, can create edaphically unique substrates. In the Americas, post-Columbian land use changes coupled with extensive loss of indigenous cultural knowledge, has created areas where associations of cultivated plants with human-generated habitats may be lost. Here we use population genetic approaches to examine rare Tephrosia (hoary pea) taxa from South Florida, a group of plants that produce rotenone that has been used by many indigenous groups as a fish poison. We find evidence of multiple introductions from the broader Caribbean region and an association with anthropogenic habitats such as shell middens. In efforts to conserve rare hoary peas in Florida, an understanding of past use of the landscape by native Americans is essential.

plant biology↗

bioRxiv2022

Risk Assessment of the newly emerged H7N9 avian influenza viruses

Since the first human case in 2013, H7N9 avian influenza viruses (AIVs) have caused more than 1500 human infections with a mortality rate of approximately 40%. Despite large-scale poultry vaccination regimes across China, the H7N9 AIVs continue to persist and evolve rapidly in poultry. Recently, several strains of H7N9 AIVs have been isolated and shown the ability to escape vaccine-induced immunity. To assess the zoonotic risk of the recent H7N9 AIV isolates, we rescued viruses with hemagglutinin (HA) and neuraminidase (NA) from these H7N9 AIVs and six internal segments from PR8 virus (A/Puerto Rico/8/34 [H1N1]) and characterized their receptor binding, pH of fusion, thermal stability, plaque morphology and in ovo virus replication. We also assessed the cross-reactivity of the viruses with human monoclonal antibodies (mAbs) against H7N9 HA and ferret antisera against H7N9 AIV candidate vaccines. The H7N9 AIVs from the early epidemic waves had dual sialic acid receptor binding characteristics, whereas the more recent H7N9 AIVs completely lost or retained only weak human sialic acid receptor binding. Compared with the H7N9 AIVs from early epidemic waves (2013-2016), the recent (2020/21) viruses formed larger plaques and increased replication titres in ovo, demonstrating increased acid stability but reduced thermal stability. Further analysis showed that these recent H7N9 AIVs had poor cross-reactivity with the human mAbs and ferret antisera, highlighting the need to update the vaccine candidates. To conclude, the newly emerged H7N9 AIVs showed characteristics of typical AIVs, posing reduced zoonotic risk but a heightened threat for poultry.

microbiology↗