Model System Research Articles

69 The Holos model for estimating greenhouse gases and soil carbon: Characterizing regionalized beef farm model systems

Abstract The objective of this work is to characterize regionally representative beef farm systems that represent dominant or typical surveyed management practices for 11 beef-producing regions across Canada. This work fulfills two further purposes 1) to improve and expand the Holos model interface; and 2) to facilitate the estimation of greenhouse gas (GHG) emissions and soil carbon (C) changes on beef farms in different regions of Canada. Holos version 4 is the whole-farm model of Agriculture and Agri-Food Canada’s to estimate GHG emissions and changes in soil C on Canadian farms in response to shifts in management practices. Holos can be implemented in all 10 Canadian provinces and accounts for GHG emissions from crop and livestock production [enteric and manure methane (CH4), manure and soil N2O emissions], farm machines and infrastructure [on-farm energy carbon dioxide (CO2) emissions], as well as from the upstream production of some farm inputs (synthetic fertilizer and pesticides). The model is designed to utilize data readily available on the farm to answer, ‘What if?’ scenarios, whereby the user can test the effect of changing management practices on their whole-farm GHG budget. To reduce the data input burden on the user, Holos V4 has built-in model livestock systems for beef, dairy, swine and poultry production that characterize the dominant features of these operations in Canada at the national scale based on relevant literature/data and expert opinion. Regarding beef production, we have characterized regionally specific model beef farms for incorporation into Holos, one for each of 11 Canadian beef-producing regions. General characteristics and management practices for each farm were based on the 2011 Beef Farm Survey (Sheppard et al., 2015), which summarizes management information from 1,009 Canadian beef farms, combined with data from the Canadian Cow-Calf Cost of Production Network (Canfax 2023). Each regional farm includes cow-calf, backgrounding in confinement, backgrounding on pasture and finishing components, and considers all the specific feed (e.g., forage, grains, by-products) required for each stage of the beef cycle. These 11 model farms are simulated within the current Holos V4 model to explore the impacts of variation in beef management practices on farm GHG emissions across Canada and on soil C stocks on lands used to produce feed and graze cattle. An overview of the national-level dairy, swine and poultry components in Holos will be presented along with a more detailed perspective of whole-farm GHG budget and multi-decadal soil C dynamics in regionalized beef farms. The impact of management and environmental factors that lead to differences in GHG emissions and soil C stocks in beef farms will also be explored.

Nanoscale elemental and morphological imaging of nitrogen-fixing cyanobacteria.

Nitrogen-fixing cyanobacteria bind atmospheric nitrogen and carbon dioxide using sunlight. This experimental study focused on a laboratory-based model system, Anabaena sp., in nitrogen-depleted culture. When combined nitrogen is scarce, the filamentous procaryotes reconcile photosynthesis and nitrogen fixation by cellular differentiation into heterocysts. To better understand the influence of micronutrients on cellular function, 2D and 3D synchrotron X-ray fluorescence mappings were acquired from whole biological cells in their frozen-hydrated state at the Bionanoprobe, Advanced Photon Source. To study elemental homeostasis within these chain-like organisms, biologically relevant elements were mapped using X-ray fluorescence spectroscopy and energy-dispersive X-ray microanalysis. Higher levels of cytosolic K+, Ca2+, and Fe2+ were measured in the heterocyst than in adjacent vegetative cells, supporting the notion of elevated micronutrient demand. P-rich clusters, identified as polyphosphate bodies involved in nutrient storage, metal detoxification and osmotic regulation, were consistently co-localized with K+ and occasionally sequestered Mg2+, Ca2+, Fe2+, and Mn2+ ions. Machine-learning based k-mean clustering revealed that P/K clusters were associated with either Fe or Ca, with Fe and Ca clusters also occurring individually. In accordance with XRF nanotomography, distinct P/K-containing clusters close to the cellular envelope were surrounded by larger Ca-rich clusters. The transition metal Fe, which is part of nitrogenase enzyme, was detected as irregular shaped clusters. The elemental composition and cellular morphology of diazotrophic Anabaena sp. was visualized by multimodal imaging using AFM, SEM, and fluorescence microscopy. This paper discusses the first experimental results obtained with a combined in-line optical and X-ray fluorescence microscope at the Bionanoprobe.

ASSEMBLING THE TURBOID-CONTAINING PLASMID CONSTRUCT FOR INVESTIGATING THE IN VIVO PROTEIN-PROTEIN INTERACTIONS

In vivo interactions between biomolecules (Proteins, RNA, and DNA) are the basis of cellular functionality including cell cycle, signaling pathways, cellular metabolism, and other biological processes. The traditional methods for detecting protein-protein interactions, such as affinity purification and two-hybrid analysis have limitations for the in-depth study of the cellular proteome. Besides, proteomics of the organelle protein components is still challenging to study, due to the spatial and temporal dynamics of proteins. To address these problems, proximity labeling technology was introduced. This technology not only surpasses all the limitations of traditional methods but also has unique advantages in the qualitative and quantitative analysis of the proteome of living cells. Proximity labeling is one of the most commonly used methods for detecting the functional features and protein composition of target proteins and neighboring ones, through biotin labeling (biotinylation). Biotin is employed due to its high affinity to streptavidin and avidin, which is an efficient procedure to purify and isolate fractions containing biotinylated proteins for further analysis. During the in vivo biotinylation study, we used the mutant biotin ligase TurboID which is the modified enzyme of BirA. BirA is an enzyme found in E. coli bacteria, capable of catalyzing the attachment of biotin to specific lysine residues on a single cellular protein. The development of TurboID involved introducing specific mutations into the BirA sequence to improve its performance. These mutations result in the inability of the TurboID biotin ligase to maintain biotinyl-5'-adenylate in its active form, causing its release from the active center into the surrounding environment. This released substance contains a reactive mixed anhydride bond, enabling it to readily modify lysine residues of nearby proteins within 10nm in the cell. So, the advantage of TurboID-X (X-any protein of interest (POI)) is that it has a high efficiency for in vivo proximity labeling. We use the PTF (pluripotency transcription factors) SOX2, OCT4, and NANOG for X as model systems. In our study, we used genetic engineering methods to obtain recombinant plasmid DNA containing the nucleotide sequence of TurboID and fused protein of interest X. DNA plasmid constructs have next key structural elements: Kozak sequence at the beginning of the fragment, His-Tag, and diglycine sequence at the end, BglII and XhoI restriction sites respectively to replace the wild-type biotin ligase BirA by TurboID. Two rounds of PCR amplification were performed, the first one using terminal primers that amplify only the TurboID ORF. The resulting amplicon of TurboID was applied as a matrix in the second PCR round by using long primers that contain the structural elements mentioned above. Expression of recombinant proteins from the resulting plasmid constructs will be demonstrated in HEK293T (Human embryonic kidney) cells using transient transfection with calcium phosphate method or Lipofectamine 2000. In conclusion, further research will consist of affinity purification, detection of labeled proteins by Western blotting, and their identification by the LC-MS/MS. We hope that our research work will help us to better understand the mechanisms of the early stages of the reprogramming process.

High-yield, plant-based production of an antimicrobial peptide with potent activity in a mouse model.

Plants offer a promising chassis for the large-scale, cost-effective production of diverse therapeutics, including antimicrobial peptides (AMPs). However, key advances will reduce production costs, including simplifying the downstream processing and purification steps. Here, using Nicotiana benthamiana plants, we present an improved modular design that enables AMPs to be secreted via the endomembrane system and sequestered in an extracellular compartment, the apoplast. Additionally, we translationally fused an AMP to a mutated small ubiquitin-like modifier sequence, thereby enhancing peptide yield and solubilizing the peptide with minimal aggregation and reduced occurrence of necrotic lesions in the plant. This strategy resulted in substantial peptide accumulation, reaching around 2.9 mg AMP per 20 g fresh weight of leaf tissue. Furthermore, the purified AMP demonstrated low collateral toxicity in primary human skin cells, killed pathogenic bacteria by permeabilizing the membrane and exhibited anti-infective efficacy in a preclinical mouse (Mus musculus) model system, reducing bacterial loads by up to three orders of magnitude. A base-case techno-economic analysis demonstrated the economic advantages and scalability of our plant-based platform. We envision that our work can establish plants as efficient bioreactors for producing preclinical-grade AMPs at a commercial scale, with the potential for clinical applications.

Study on the condensate gas phase behavior in Nano-porous media

The pore size in shale has reached the nanoscale. The phase behavior of fluids in nanopores deviates from classical theory, making conventional phase theory inapplicable to shale reservoirs. It is thus of great significance to clarify the phase behavior at the nanometer pore scale in shale. Based on the shale reservoir in the Kaybob of the Duvernay shale, Canada, 6 nm and 10 nm cubic model systems were constructed, and a microscopic physical model was prepared included pathways at 10 nm, 40 nm, 500 nm, and micrometer scale. The fluid phase behavior in nanopores was studied using molecular simulations and nanofluidic chip experiments. The results show that during the retrograde condensation process, the condensate gas in small-scale pores condenses first and is less likely to evaporate as the pressure decreases. The conclusions drawn are: (1) In nanopores, the dew point pressure of condensate gas is higher than that of the bulk phase, and the smaller the scale of nanopores, the higher the dew point pressure. (2) The volume ratio of condensate in nanopores is higher, increasing as pore size decreases. (3) The condensation rate of condensate in nanoporous media varies slowly with pressure drop; During evaporation, the condensation rate of condensate in small pores varies more slowly with pressure drop compared to the bulk phase but is faster in large pores.

Selective Degradation of MLK3 by a Novel CEP1347-VHL-02 PROTAC Compound Limits the Oncogenic Potential of TNBC.

Triple-negative breast cancer (TNBC) is associated with poor prognosis because of the lack of effective therapies. Mixed-lineage protein kinase 3 (MLK3) is a protein that is often upregulated in TNBC and involved in driving the tumorigenic potential of cancer cells. Here, we present a selective MLK3 degrader, CEP1347-VHL-02, based on the pan-MLK inhibitor CEP1347 and a ligand for E3 ligase von Hippel-Lindau (VHL) by employing proteolysis-targeting chimera (PROTAC) technology. Our compound effectively targeted MLK3 for degradation via the ubiquitin-proteasome system in several cell line models but did not degrade other MLK family members. Furthermore, we showed that CEP1347-VHL-02 robustly degraded MLK3 and inhibited its oncogenic activity in TNBC, measured as a reduction of clonogenic and migratory potential, cell cycle arrest, and the induction of apoptosis in MDA-MB-468 cells. In conclusion, we present CEP1347-VHL-02 as a novel MLK3 degrader that may be a promising new strategy to target MLK3 in TNBC.

Innovative device for crack monitoring and deflection analysis in structures: Improved accuracy, safety and efficiency

It is of the utmost importance to ensure the structural integrity of buildings in order to guarantee the safety of their occupants. Conventional techniques for monitoring cracks and conducting flexural analysis during loading and unloading tests frequently prove inadequate in terms of accuracy and safety. This study introduces ES1293890 U, an innovative dual-purpose device designed for the precise remote monitoring of cracks and comprehensive flexural analysis. The device is integrated seamlessly into structural health monitoring (SHM) and building information modelling (BIM) systems, thereby providing a holistic approach to structural assessment.The ES1293890 U device offers superior accuracy, with a resolution of 0.01 mm and a maximum deviation of 0.007 mm, which makes it a more effective alternative to existing commercial solutions. The utilisation of recycled and biodegradable materials has the effect of reducing production costs, thereby facilitating the undertaking of more frequent and economically viable testing and monitoring. This enhanced affordability is of paramount importance for the maintenance of building safety and structural integrity through regular assessments.A noteworthy attribute of the ES1293890 U is its capacity to conduct remote measurements, obviating the necessity for professionals to enter potentially hazardous test areas. This not only ensures the safety of personnel but also enables continuous and uninterrupted monitoring, with real-time data capture facilitating timely and informed decision-making.In comparison to traditional gauges, the ES1293890 U exhibits enhanced performance in the monitoring of slab deflections, attributable to its elevated accuracy and comprehensive data acquisition capabilities. This device represents a substantial advancement in structural assessment technology, providing a reliable and efficient tool for improving building safety and integrity. The ES1293890 U's innovative approach and cost-effective design have the potential to revolutionise structural monitoring practices, making it an invaluable asset to both the scientific community and the construction industry.

Recurrent Independent Pseudogenization Events of the Sperm Fertilization Gene ZP3r in Apes and Monkeys.

Many reproductive proteins show signatures of rapid evolution through sequence divergence and duplication. These features of reproductive genes may complicate the detection of orthologs across taxa, making it difficult to connect studies in model systems to human biology. In mice, ZP3r/sp56 is a binding partner to the egg coat protein ZP3 and may mediate induction of the acrosome reaction, a crucial step in fertilization. In rodents, ZP3r, as a member of the Regulators of Complement Activation cluster, is surrounded by paralogs, some of which have been shown to be evolving under positive selection. Although primate egg coats also contain ZP3, sequence divergence paired with paralogous relationships with neighboring genes has complicated the accurate identification of the human ZP3r ortholog. Here, we phylogenetically and syntenically resolve that the human ortholog of ZP3r is the pseudogene C4BPAP1. We investigate the evolution of this gene within primates. We observe independent pseudogenization events of ZP3r in all Apes with the exception of Orangutans, and independent pseudogenization events in many monkey species. ZP3r in both primates that retain ZP3r and in rodents contains positively selected sites. We hypothesize that redundant mechanisms mediate ZP3 recognition in mammals and ZP3r's relative importance to ZP recognition varies across species.

Epitaxial Growth of Monolayer WS2 Single Crystals on Au(111) Toward Direct Surface-Enhanced Raman Spectroscopy Detection.

The epitaxial growth of wafer-scale two-dimensional (2D) semiconducting transition metal dichalcogenides (STMDCs) single crystals is the key premise for their applications in next-generation electronics. Despite significant advancements, some fundamental factors affecting the epitaxy growth have not been fully uncovered, e.g., interface coupling strength, adlayer-substrate lattice matching, substrate step-edge-guiding effects, etc. Herein, we develop a model system to tackle these issues concurrently, and realize the epitaxial growth of wafer-scale monolayer tungsten disulfide (WS2) single crystals on the Au(111) substrate. This epitaxial system is featured with good adlayer-substrate lattice matching, obvious step-edge-guiding effect for the unidirectionally aligned nucleation/growth, and relatively weaker interfacial interaction than that of monolayer MoS2/Au(111), as evidenced by the evolution of a uniform Moiré pattern and an intrinsic band gap, according to on-site scanning tunneling microscopy/spectroscopy (STM/STS) characterizations and density functional theory calculations. Intriguingly, the unidirectionally aligned monolayer WS2 domains along the Au(111) steps can behave as ultrasensitive templates for surface-enhanced Raman scattering detection of organic molecules, due to the obvious charge transfer occurred at substrate step edges. This work should hereby deepen our understanding of the epitaxy mechanism of 2D STMDCs on single-crystal substrates, and propel their wafer-scale production and applications in various cutting-edge fields.

Prebiotic chiral transfer from self-aminoacylating ribozymes may favor either handedness

Modern life is essentially homochiral, containing D-sugars in nucleic acid backbones and L-amino acids in proteins. Since coded proteins are theorized to have developed from a prebiotic RNA World, the homochirality of L-amino acids observed in all known life presumably resulted from chiral transfer from a homochiral D-RNA World. This transfer would have been mediated by aminoacyl-RNAs defining the genetic code. Previous work on aminoacyl transfer using tRNA mimics has suggested that aminoacylation using D-RNA may be inherently biased toward reactivity with L-amino acids, implying a deterministic path from a D-RNA World to L-proteins. Using a model system of self-aminoacylating D-ribozymes and epimerizable activated amino acid analogs, we test the chiral selectivity of 15 ribozymes derived from an exhaustive search of sequence space. All of the ribozymes exhibit detectable selectivity, and a substantial fraction react preferentially to produce the D-enantiomer of the product. Furthermore, chiral preference is conserved within sequence families. These results are consistent with the transfer of chiral information from RNA to proteins but do not support an intrinsic bias of D-RNA for L-amino acids. Different aminoacylation structures result in different directions of chiral selectivity, such that L-proteins need not emerge from a D-RNA World.

Establishment and validation of a predictive model for spontaneous preterm birth in singleton pregnant women

IntroductionIn the current study, we screened for highly sensitive and specific predictors of premature birth, with the aim to establish an sPTB prediction model that is suitable for women in China and easy to operate and popularize, as well as to establish a sPTB prediction scoring system for early, intuitive, and effective assessment of premature birth risk.MethodsA total of 685 pregnant women with a single pregnancy during the second trimester (16–26 weeks) were divided into premature and non-premature delivery groups based on their delivery outcomes. Clinical and ultrasound information were collected for both groups, and risk factors that could lead to sPTB in pregnant women were screened and analyzed using a cut-off value. A nomogram was developed to establish a prediction model and scoring system for sPTB. In addition, 119 pregnant women who met the inclusion criteria for the modeling cohort were included in the external validation of the model. The accuracy and consistency of the model were evaluated using the area under the receiver operating characteristic (ROC) and C-calibration curves.ResultsMultivariate logistic regression analysis showed a significant correlation (P < 0.05) between the number of miscarriages in pregnant women, history of miscarriages in the first week of pregnancy, history of preterm birth, CL of pregnant women, open and continuous cervical opening, and the occurrence of sPTB in pregnant women. We drew a nomogram column chart based on the six risk factors mentioned above, obtained a predictive model for sPTB, and established a scoring system to divide premature birth into three risk groups: low, medium, and high. After validating the model, the Hosmer Lemeshow test indicated a good fit (p = 0.997). The modeling queue C calibration curve was close to diagonal (C index = 0.856), confirming that the queue C calibration curve was also close to diagonal (C index = 0.854). The AUCs of the modeling and validation queues were 0.850 and 0.881, respectively.ConclusionOur predictive model is consistent with China’s national conditions, as well as being intuitive and easy to operate, with wide applicability, thus representing a helpful tool to assist with early detection of sPTB in clinical practice, as well as for clinical management in assessing low, medium, and high risks of sPTB.

Development and validation of an experimental life support system to study coral reef microbial communities

In the present study, we developed and validated an experimental life support system (ELSS) designed to investigate coral reef associated bacterial communities. The microcosms in the ELSS consisted of coral reef sediment, synthetic seawater, and specimens of five benthic reef species. These included two hard corals Montipora digitata and Montipora capricornis, a soft coral Sarcophyton glaucum, a zoanthid Zoanthus sp., and a sponge Chondrilla sp.. Physicochemical parameters and bacterial communities in the ELSS were similar to those observed at shallow coral reef sites. Sediment bacterial evenness and higher taxonomic composition were more similar to natural-type communities at days 29 and 34 than at day 8 after transfer to the microcosms, suggesting microbial stabilization after an initial recovery period. Biotopes were compositionally distinct but shared a number of ASVs. At day 34, sediment specific ASVs were found in hosts and visa versa. Transplantation significantly altered the bacterial community composition of M. digitata and Chondrilla sp., suggesting microbial adaptation to altered environmental conditions. Altogether, our results support the suitability of the ELSS developed in this study as a model system to investigate coral reef associated bacterial communities using multi-factorial experiments.

Evolutionary innovation accelerates morphological diversification in pufferfishes and their relatives.

Evolutionary innovations have played an important role in shaping the diversity of life on Earth. However, how these innovations arise, and their downstream effects on patterns of morphological diversification remain poorly understood. Here, we examine the impact of evolutionary innovation on trait diversification in tetraodontiform fishes (pufferfishes, boxfishes, ocean sunfishes, and allies). This order provides an ideal model system for studying morphological diversification owing to their range of habitats and divergent morphologies, including the fusion of the teeth into a beak in several families. Using three-dimensional geometric morphometric data for 176 extant and fossil species, we examine the effect of skull integration and novel habitat association on the evolution of innovation. Strong integration may be a requirement for rapid trait evolution and facilitating the evolution of innovative structures, like the tetraodontiform beak. Our results show that the beak arose in the presence of highly conserved patterns of integration across the skull, suggesting that integration did not limit the range of available phenotypes to tetraodontiforms. Furthermore, we find that beaks have allowed tetraodontiforms to diversify into novel ecological niches, irrespective of habitat. Our results suggest that general rules pertaining to evolutionary innovation may be more nuanced than previously thought.

Big1 is a newly identified autophagy regulator that is critical for a fully functional V-ATPase.

The vacuolar H+-translocating ATPase (V-ATPase) is the major proton pump for intra-organellar acidification. Therefore, the integrity of the V-ATPase is closely associated with cellular homeostasis, and mutations in genes encoding V-ATPase components and assembly factors have been reported in certain types of diseases. For instance, the recurrent mutations of ATP6AP1, a gene encoding a V-ATPase accessory protein, have been associated with cancers and immunodeficiency. With the aim of studying V-ATPase-related mutations using the yeast model system, we report that Big1 is another homolog of ATP6AP1 in yeast cells, and we characterize the role of Big1 in maintaining a fully functional V-ATPase. In addition to its role in acidifying the vacuole or lysosome, our data support the concept that the V-ATPase may function as part of a signaling pathway to regulate macroautophagy/autophagy through a mechanism that is independent from Tor/MTOR.

Numerical integration of mechanical forces in center-based models for biological cell populations

Center-based models are used to simulate the mechanical behavior of biological cells during embryonic development or cancer growth. To allow for the simulation of biological populations potentially growing from a few individual cells to many thousands or more, these models have to be numerically efficient, while being reasonably accurate on the level of individual cell trajectories. In this work, we increase the robustness, accuracy, and efficiency of the simulation of center-based models by choosing the time steps adaptively in the numerical method and comparing five different integration methods. We investigate the gain in using single rate time stepping based on local estimates of the numerical errors for the forward and backward Euler methods of first order accuracy and a Runge-Kutta method and the trapezoidal method of second order accuracy. Properties of the analytical solution such as convergence to steady state and conservation of the center of gravity are inherited by the numerical solutions. Furthermore, we propose a multirate time stepping scheme that simulates regions with high local force gradients (e.g. as they happen after cell division) with multiple smaller time steps within a larger single time step for regions with smoother forces. These methods are compared for a model system in numerical experiments. We conclude, for example, that the multirate forward Euler method performs better than the Runge-Kutta method for low accuracy requirements but for higher accuracy the latter method is preferred. Only with frequent cell divisions the method with a fixed time step is the best choice.

Unveiling crystal orientation-dependent interface property in composite cathodes for solid-state batteries by in situ microscopic probe

A critical bottleneck toward all-solid-state batteries lies in how the solid(electrode)-solid(electrolyte) interface is fabricated and maintained over repeated cycles. Conventional composite cathodes, with crystallographically distinct electrode/electrolyte interfaces of random particles, create complexities with varying (electro)chemical compatibilities. To address this, we employ an epitaxial model system where the crystal orientations of cathode and solid electrolyte are precisely controlled, and probe the interfaces in real-time during co-sintering by in situ electron microscopy. The interfacial reaction is highly dependent on crystal orientation/alignment, especially the availability of open ion channels. Interfaces bearing open ion paths of NCM are more susceptible to interdiffusion, but stabilize with the early formed passivation layer. Conversely, interfaces with closed ion pathway exhibit stability at intermediate temperatures, but deteriorate rapidly at high temperature due to oxygen evolution, increasing interfacial resistance. The elucidation of these distinct interfacial behaviors emphasizes the need for decoupling collective interfacial properties to enable rational design in solid-state batteries.

Enriching productive mutational paths accelerates enzyme evolution.

Darwinian evolution has given rise to all the enzymes that enable life on Earth. Mimicking natural selection, scientists have learned to tailor these biocatalysts through recursive cycles of mutation, selection and amplification, often relying on screening large protein libraries to productively modulate the complex interplay between protein structure, dynamics and function. Here we show that by removing destabilizing mutations at the library design stage and taking advantage of recent advances in gene synthesis, we can accelerate the evolution of a computationally designed enzyme. In only five rounds of evolution, we generated a Kemp eliminase-an enzymatic model system for proton transfer from carbon-that accelerates the proton abstraction step >108-fold over the uncatalyzed reaction. Recombining the resulting variant with a previously evolved Kemp eliminase HG3.17, which exhibits similar activity but differs by 29 substitutions, allowed us to chart the topography of the designer enzyme's fitness landscape, highlighting that a given protein scaffold can accommodate several, equally viable solutions to a specific catalytic problem.

Analysis of the effect of HDAC inhibitors on the formation of the HIV reservoir.

The HIV reservoir is more dynamic than previously thought with around 70% of the latent reservoir originating from viruses circulating within 1 year of the initiation of antiretroviral therapy (ART). In an ex vivo model system of HIV latency, it was reported that early exposure to class I histone deacetylase (HDAC) inhibitors might prevent these more recently infected cells from entering a state of stable viral latency. This finding raises the possibility that co-administration of HDAC inhibitors at the time of ART initiation may prevent the establishment of much of the HIV reservoir. Here, we tested the effects of the HDAC inhibitors suberoylanilide hydroxamic acid (SAHA) and panobinostat co-administered at the time of ART initiation on the formation of the viral reservoir in HIV-infected humanized mice. As previously shown, SAHA and panobinostat were well tolerated in humanized mice. Unexpectedly, co-administration of SAHA resulted in an increase in the frequency of CD4+ cells carrying HIV DNA but did not alter the frequency of cell-associated HIV RNA in HIV-infected, ART-treated humanized mice. Co-administration of panobinostat did not alter levels of cell-associated HIV DNA or RNA. Our in vivo findings indicate that co-administration of HDAC inhibitors initiated at the same time of ART treatment does not prevent recently infected cells from entering latency.IMPORTANCECurrent antiretroviral therapy (ART) does not eradicate cells harboring replication-competent HIV reservoir. Withdrawal of ART inevitably results in a rapid viremia rebound. The HIV reservoir is more dynamic than previously thought. Early exposure to class I histone deacetylase (HDAC) inhibitors inhibit these more recently infected cells from entering a state of stable viral latency in an ex vivo model of latency, raising the possibility that co-administration of HDAC inhibitors at the time of ART initiation may reduce much of the HIV reservoir. Here, we tested the effects of the HDAC inhibitors suberoylanilide hydroxamic acid or panobinostat during ART initiation on the formation of the viral reservoir in HIV-infected humanized mice. Our in vivo study indicates that in contrast to in vitro observations, the co-administration of HDAC inhibitors at the same time of ART initiation does not prevent recently infected cells from entering latency.

Gut microbiota influences onset of foraging-related behavior but not physiological hallmarks of division of labor in honeybees.

The honeybee is emerging as a model system for studying gut microbiota-host interactions. Previous studies reported gut microbiota effects on multiple worker bee phenotypes, all of which change during behavioral maturation-the transition from nursing to foraging. We tested whether the documented effects may stem from an effect of the microbiota on behavioral maturation. The gut microbiota only subtly affected maturation: it accelerated the onset of foraging without affecting the overall proportion of foragers or their average output. We also found no effect of the microbiota on host weight, cuticular hydrocarbon (CHC) profile, hypopharyngeal gland size, and the expression of behavioral maturation-related genes. These results are inconsistent with previous studies reporting effects of the gut microbiota on bee weight and CHC profile. Our experiments revealed that co-housed bees tend to converge in behavior and physiology, suggesting that spurious associations may emerge when rearing environments are not replicated sufficiently or accounted for analytically.

A regional One Health approach to the risk of invasion by Anopheles stephensi in Mauritius.

Anopheles stephensi is an invasive malaria vector in Africa that threatens to put an additional 126 million people at risk of malaria if it continues to spread. The island nation of Mauritius is highly connected to Asia and Africa and is at risk of introduction due to this connectivity. For early detection of An. stephensi, the Vector Biology and Control Division under the Ministry of Health in Mauritius, leveraged a well-established Aedes program, as An. stephensi is known to share Aedes habitats. These efforts triggered multisectoral coordination and cascading benefits of integrated vector and One Health approaches. Beginning June 2021, entomological surveys were conducted at points of entry (seaport, airport) and on ships transporting livestock in collaboration with the Civil Aviation Department, the Mauritian Port Authority and National Veterinary Services. A total of 18, 39, 723 mosquito larval surveys were respectively conducted in the airport, seaport, and other localities in Mauritius while two, 20, and 26 adult mosquito surveys were respectively conducted in the airport, seaport, and twenty-six animal assembly points. Alongside adult mosquito surveys, surveillance of vectors of veterinary importance (e.g.- Culicoides spp.) was also carried out in collaboration with National Parks and Conservation Service and land owners. A total of 8,428 adult mosquitoes were collected and 1,844 larval habitats were positive for mosquitoes. All collected mosquitoes were morphologically identified and 151 Anopheles and 339 Aedes mosquitoes were also molecularly characterized. Mosquito species detected were Aedes albopictus, Anopheles arabiensis, An. coustani, An. merus, Culex quinquefasciatus, Cx. thalassius and Lutzia tigripes. Anopheles stephensi was not detected. The One Health approach was shared with the French Agricultural Research Centre for International Development (CIRAD), strengthening collaboration between Mauritius and Réunion Island on vector surveillance at entry points and insecticide resistance monitoring. The Indian Ocean Commission (IOC) was also alerted to the risk of An. stephensi, leading to regional efforts supporting trainings and development of a response strategy to An. stephensi bringing together stakeholders from Comoros, Madagascar, Mauritius, Réunion Island and Seychelles. Mauritius is a model system showing how existing public health entomology capabilities can be used to enhance vector surveillance and control and create multisectoral networks to respond to any emerging public and veterinary health vector-borne disease threat.