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BACKGROUND: The isolated finding of an unexplained chronic subdural haematoma in an infant may suggest non-accidental head injury (NAHI). The authors report a previously undescribed cause of multifocal chronic subdural haematoma in infancy which could result in a misdiagnosis of previous NAHI. METHODS: Two infants, aged 3 and 4 months of age, presented with progressively increasing head circumference measurements from birth. There was no history of encephalopathy. Retinal haemorrhages were not present. CT and MRI demonstrated bilateral subdural fluid collections over the frontal regions that were consistent with either chronic subdural haematomas or haemorrhagic subdural effusions. In view of the possibility of NAHI, child protection investigations were initiated. FINDINGS: In neither case did the child protection investigations raise concerns. Comprehensive investigations for known haematological and metabolic disorders associated with subdural haematomas or effusions in infants were all normal. In both cases the infant's mother had a history of Sjögren's syndrome and both infants had positive anti-Ro antibody at presentation. CONCLUSIONS: Transplacental acquisition of anti-Ro antibodies has been associated with external hydrocephalus. External hydrocephalus has been recognised as a predisposing factor for subdural haemorrhage. These are the first reported cases linking the presence of anti-Ro antibodies and external hydrocephalus with subdural fluid collections in infancy. [ABSTRACT FROM AUTHOR]

Encourage patient and staff satisfaction by implementing family centered care with a flexible structure and effective security. [ABSTRACT FROM AUTHOR]

We have investigated the mutagenicity of benzo[α]pyrene (B[α]P) in small intestine using the Dlb-1 locus assay in the mouse. Administration of B[α]P by the oral and i.p. routes had markedly different effects on the number of Dlb-1 mutations and the pattern of induction of cytochrome P-4501A1 (CYP1A1). In Ahr-responsive animals i.p. injection resulted in marked induction in crypt cells along the length of the small intestine, with some induction in the villus cells. In contrast, after oral administration, CYP1A1 induction was evident only in the villus cells, and this declined distally. The intensity and speed of induction in Ahr-responsive animals was such that the genotoxic effect of a single injection of B[α]P could not be augmented by prior treatment with non-genotoxic inducers such as β-napthoflavone and TCDD. Oral B[α]P treatment resulted in a decrease in the number of mutations when compared with the i.p. route. Studies in congenic Ahr-non-responsive versus Ahr-responsive mice indicated that induction of CYP1A1 was associated with increased number of Dlb-1 mutations. Mutation induction in Ahr-non-responsive mice in the absence of detectable CYP1A1 in either liver or small intestine indicates that an appreciable portion of B[α]P activation to a genotoxin must be by other than a CYP1A1 mediated route. These data show that B[α]P is a potent small intestinal mutagen at the Dlb-1 locus. [ABSTRACT FROM PUBLISHER]

1. In previous studies (Boobis et al., 1985b) it was shown that a monoclonal antibody (MAb 3/4/2), raised against rat cytochrome P450 form c, reacts with an isoenzyme(s) of cytochrome P450 in human liver. It was predicted that the epitope with which this antibody reacts should be present on both isoenzymes of the P450IA gene sub-family (the orthologues of forms c and d) in man (Edwards et al., 1987). 2. This antibody was used to probe 45 different samples of human liver, by the technique of Western blotting. With one exception, all of the samples contained immunoreactive protein, a single band at Mr 54,000 (orthologous to rat form d), which ranged in content from less than 0.5 to 33.5 pmol mg-1 microsomal protein. The content of the human orthologue of form c was below 0.5 pmol mg-1, the limit of detection of the assay. 3. Thirteen of the samples were from patients of known smoking status. Immunoreactive P450 content was 3.5-fold higher, and phenacetin O-deethylase activity was four-fold higher, in the smokers than in the non-smokers. 4. There was a highly significant correlation between the amount of immunoreactive cytochrome P450 and the high affinity component of phenacetin O-deethylase activity in both smokers and non-smokers. 5. It is concluded that the high affinity component of phenacetin O-deethylase activity in man is catalysed by the orthologue of rat cytochrome P450d, and that this isoenzyme is inducible by cigarette smoking. 6. In a number of previous publications it has been suggested that there is an association between the poor metaboliser (PM) phenotype for debrisoquine and impaired phenacetin O-deethylation. In the present study it was shown that not all subjects PM for debrisoquine are poor metabolisers of phenacetin. [ABSTRACT FROM AUTHOR]

Data on persons with perinatally acquired HIV infection in the Caribbean are limited; thus, a chart review was conducted among these clients at an adult HIV treatment clinic in Trinidad over the period January 01, 2011-June 30, 2023. Sociodemographic, clinical, and laboratory data were extracted and analyzed using RStudio version 2021.09.0. Fifty-four study participants were followed up, age range 18-29 years, and there were 27 (50%) males. Eighteen participants (33.3%) were institutionalized until the age of 18 years, while 36 (66.7%) lived with caregivers/relatives and attended outpatient pediatric clinic. The transition from the sheltered environment of pediatric care to the adult HIV clinic was turbulent for some participants as they experienced HIV-related stigma, which may result in poor HIV outcomes. At the initial clinic visit, 28 (51.9%) study participants were virally suppressed (HIV viral load <1,000 copies/mL), which included 12 (66.7%) of 18 who were institutionalized as compared to 16 (44.4%) of 38 who lived with caregivers/relatives ( p = 0.387). Data from their last clinic visit showed 31 (57.4%) participants were virally suppressed; 13 (24.1%) were lost to follow-up from care, and there were 6 (11.1%) deaths; 29 (53.7%) were on antiretroviral therapy single-tablet regimens (STRs) and 25 (46.3%) on complex multiple-tablet regimens (MTRs). Institutionalized clients and those on STRs were more likely to be virally suppressed than those living with relatives ( p = 0.043) and those on MTR ( p < 0.001), respectively. Reported deaths were higher among clients who lived with caregivers/relatives and those on MTR. Participants of younger age were less likely to achieve viral suppression ( p = 0.02). Comprehensive programs that include STRs, the engagement of caregivers/relatives and health workers, life skills, and enhanced psychosocial interventions for youths living with perinatally acquired HIV are important to support the transition to adult care and reduce the complex challenges of living with a stigmatizing disease.

Diseases of Theobroma cacao L. (Malvaceae) disrupt cocoa bean supply and economically impact growers. Vascular streak dieback (VSD), caused by Ceratobasidium theobromae, is a new encounter disease of cacao currently contained to southeast Asia and Melanesia. Resistance to VSD has been tested with large progeny trials in Sulawesi, Indonesia, and in Papua New Guinea with the identification of informative quantitative trait loci (QTLs). Using a VSD susceptible progeny tree (clone 26), derived from a resistant and susceptible parental cross, we assembled the genome to chromosome-level and discriminated alleles inherited from either resistant or susceptible parents. The parentally phased genomes were annotated for all predicted genes and then specifically for resistance genes of the nucleotide-binding site leucine-rich repeat class (NLR). On investigation, we determined the presence of NLR clusters and other potential disease response gene candidates in proximity to informative QTLs. We identified structural variants within NLRs inherited from parentals. We present the first diploid, fully scaffolded, and parentally phased genome resource for T. cacao L. and provide insights into the genetics underlying resistance and susceptibility to VSD., (© 2024 The Author(s). The Plant Genome published by Wiley Periodicals LLC on behalf of Crop Science Society of America.)

Broadly reactive antibodies that target sequence-diverse antigens are of interest for vaccine design and monoclonal antibody therapeutic development because they can protect against multiple strains of a virus and provide a barrier to evolution of escape mutants. Using LIBRA-seq (linking B cell receptor to antigen specificity through sequencing) data for the B cell repertoire of an individual chronically infected with human immunodeficiency virus type 1 (HIV-1), we identified a lineage of IgG3 antibodies predicted to bind to HIV-1 Envelope (Env) and influenza A Hemagglutinin (HA). Two lineage members, antibodies 2526 and 546, were confirmed to bind to a large panel of diverse antigens, including several strains of HIV-1 Env, influenza HA, coronavirus (CoV) spike, hepatitis C virus (HCV) E protein, Nipah virus (NiV) F protein, and Langya virus (LayV) F protein. We found that both antibodies bind to complex glycans on the antigenic surfaces. Antibody 2526 targets the stem region of influenza HA and the N-terminal domain (NTD) region of SARS-CoV-2 spike. A crystal structure of 2526 Fab bound to mannose revealed the presence of a glycan-binding pocket on the light chain. Antibody 2526 cross-reacted with antigens from multiple pathogens and displayed no signs of autoreactivity. These features distinguish antibody 2526 from previously described glycan-reactive antibodies. Further study of this antibody class may aid in the selection and engineering of broadly reactive antibody therapeutics and can inform the development of effective vaccines with exceptional breadth of pathogen coverage., Competing Interests: M.J.V., A.R.S., and I.S.G. are listed as inventors on patents filed describing the antibodies discovered here. I.S.G. is listed as an inventor on the patent applications for the LIBRA-seq technology. I.S.G. is a co-founder of AbSeek Bio. I.S.G. has served as a consultant for Sanofi. The Georgiev laboratory at VUMC has received unrelated funding from Merck and Takeda Pharmaceuticals. D.J.S has served as a consultant for AstraZeneca AB., (Copyright: © 2024 Vukovich et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Nucleoside-modified mRNA technology has revolutionized vaccine development with the success of mRNA COVID-19 vaccines. We used modified mRNA technology for the design of envelopes (Env) to induce HIV-1 broadly neutralizing antibodies (bnAbs). However, unlike SARS-CoV-2 neutralizing antibodies that are readily made, HIV-1 bnAb induction is disfavored by the immune system because of the rarity of bnAb B cell precursors and the cross-reactivity of bnAbs targeting certain Env epitopes with host molecules, thus requiring optimized immunogen design. The use of protein nanoparticles (NPs) has been reported to enhance B cell germinal center responses to HIV-1 Env. Here, we report our experience with the expression of Env-ferritin NPs compared with membrane-bound Env gp160 when encoded by modified mRNA. We found that well-folded Env-ferritin NPs were a minority of the protein expressed by an mRNA design and were immunogenic at 20 µg but minimally immunogenic in mice at 1 µg dose in vivo and were not expressed well in draining lymph nodes (LNs) following intramuscular immunization. In contrast, mRNA encoding gp160 was more immunogenic than mRNA encoding Env-NP at 1 µg dose and was expressed well in draining LN following intramuscular immunization. Thus, analysis of mRNA expression in vitro and immunogenicity at low doses in vivo are critical for the evaluation of mRNA designs for optimal immunogenicity of HIV-1 immunogens.IMPORTANCEAn effective HIV-1 vaccine that induces protective antibody responses remains elusive. We have used mRNA technology for designs of HIV-1 immunogens in the forms of membrane-bound full-length envelope gp160 and envelope ferritin nanoparticle. Here, we demonstrated in a mouse model that the membrane-bound form induced a better response than envelope ferritin nanoparticle because of higher in vivo protein expression. The significance of our research is in highlighting the importance of analysis of mRNA design expression and low-dose immunogenicity studies for HIV-1 immunogens before moving to vaccine clinical trials., Competing Interests: D.W., K.O.S., and B.F.H. are inventors on U.S. patent number 11,318,197 and U.S. application numbers 17/703,332 and 16/977,408 (Stabilization of Human Immunodeficiency Virus [HIV] Envelopes). B.F.H. and K.O.S. are inventors on international patent application number PCT/US2019/020436 (Compositions and Methods for Inducing HIV-1 Antibodies). M.T. is a contract employee for 3M Healthcare. All other authors declare no conflicts of interest.

The genes encoding ribosomal RNA are highly conserved across life and in almost all eukaryotes are present in large tandem repeat arrays called the rDNA. rDNA repeat unit size is conserved across most eukaryotes but has expanded dramatically in mammals, principally through the expansion of the intergenic spacer region that separates adjacent rRNA coding regions. Here, we used long-read sequence data from representatives of the major amniote lineages to determine where in amniote evolution rDNA unit size increased. We find that amniote rDNA unit sizes fall into two narrow size classes: "normal" (∼11-20 kb) in all amniotes except monotreme, marsupial, and eutherian mammals, which have "large" (∼35-45 kb) sizes. We confirm that increases in intergenic spacer length explain much of this mammalian size increase. However, in stark contrast to the uniformity of mammalian rDNA unit size, mammalian intergenic spacers differ greatly in sequence. These results suggest a large increase in intergenic spacer size occurred in a mammalian ancestor and has been maintained despite substantial sequence changes over the course of mammalian evolution. This points to a previously unrecognized constraint on the length of the intergenic spacer, a region that was thought to be largely neutral. We finish by speculating on possible causes of this constraint., Competing Interests: Conflicts of interest: The author(s) declare no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Genetics Society of America.)

A recombinant lineage of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant, named XBB, appeared in late 2022 and evolved descendants that successively swept local and global populations. XBB lineage members were noted for their improved immune evasion and transmissibility. Here, we determine cryoelectron microscopy (cryo-EM) structures of XBB.1.5, XBB.1.16, EG.5, and EG.5.1 spike (S) ectodomains to reveal reinforced 3-receptor binding domain (RBD)-down receptor-inaccessible closed states mediated by interprotomer RBD interactions previously observed in BA.1 and BA.2. Improved XBB.1.5 and XBB.1.16 RBD stability compensated for stability loss caused by early Omicron mutations, while the F456L substitution reduced EG.5 RBD stability. S1 subunit mutations had long-range impacts on conformation and epitope presentation in the S2 subunit. Our results reveal continued S protein evolution via simultaneous optimization of multiple parameters, including stability, receptor binding, and immune evasion, and the dramatic effects of relatively few residue substitutions in altering the S protein conformational landscape., Competing Interests: Declaration of interests B.F.H., K.O.S., R.J.E., S.G., and P.A. are named in patents submitted on the SARS-CoV-2 monoclonal antibodies studied in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

HIV-1, Hepatitis B and HTLV-1 have similar risk factors and shared routes of transmission and MSM are disproportionately affected by HIV. The aim of the study was to determine the prevalence of HTLV-1 and HBsAg positivity at initial enrolment among MSM attending a large HIV Clinic in Trinidad. Chart reviews were conducted between 2 and 15 January 2024, among self-identified MSM and a comparative group of randomly selected self-identified heterosexual males where sociodemographic, clinical and laboratory data were collected and analysed using SPSS Version 25. During the period April 2002-31 October 2023, in total there were 10,424 patients registered at the clinic, of whom 1255 (12.0%) were self-identified MSM, with an age range of 19-85 years and a median age of 40 years. There were 1822 randomly selected heterosexual males, with an age range of 18-94 years old and a median age of 52 years. Among the MSM, there were 21 (1.67%) patients who were HIV-1/HTLV-1-coinfected, 64 (5.10%) who were HIV-1/HBsAg-coinfected and two (0.16%) who were coinfected with all three viruses (HIV-1/HTLV-1/HBsAg) as compared to 47 ((2.58%) HIV-1/HTLV-1-coinfected ( p = 0.12), 69 (3.79%) HIV-1/HBsAg-coinfected ( p = 0.10) and three (0.16%) patients coinfected with all three viruses among the heterosexual males. There were no patients with HTLV-1-related diseases among the HIV-1/HTLV-1-coinfected patients and there were no deaths from chronic liver disease in patients coinfected with HIV-1/HBsAg. Despite the availability of an efficacious vaccine, there is a prevalence of hepatitis B of 5.1% among MSM attending the HIV Clinic in Trinidad; therefore, programmes to increase health literacy, screening and immunization are urgently needed.

Ultraconserved elements were discovered two decades ago, arbitrarily defined as sequences that are identical over a length ≥ 200 bp in the human, mouse, and rat genomes. The definition was subsequently extended to sequences ≥ 100 bp identical in at least three of five mammalian genomes (including dog and cow), and shown to have undergone rapid expansion from ancestors in fish and strong negative selection in birds and mammals. Since then, many more genomes have become available, allowing better definition and more thorough examination of ultraconserved element distribution and evolutionary history. We developed a fast and flexible analytical pipeline for identifying ultraconserved elements in multiple genomes, dedUCE, which allows manipulation of minimum length, sequence identity, and number of species with a detectable ultraconserved element according to specified parameters. We suggest an updated definition of ultraconserved elements as sequences ≥ 100 bp and ≥97% sequence identity in ≥50% of placental mammal orders (12,813 ultraconserved elements). By mapping ultraconserved elements to ∼200 species, we find that placental ultraconserved elements appeared early in vertebrate evolution, well before land colonization, suggesting that the evolutionary pressures driving ultraconserved element selection were present in aquatic environments in the Cambrian-Devonian periods. Most (>90%) ultraconserved elements likely appeared after the divergence of gnathostomes from jawless predecessors, were largely established in sequence identity by early Sarcopterygii evolution-before the divergence of lobe-finned fishes from tetrapods-and became near fixed in the amniotes. Ultraconserved elements are mainly located in the introns of protein-coding and noncoding genes involved in neurological and skeletomuscular development, enriched in regulatory elements, and dynamically expressed throughout embryonic development., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

Ninu (greater bilby, Macrotis lagotis) are desert-dwelling, culturally and ecologically important marsupials. In collaboration with Indigenous rangers and conservation managers, we generated the Ninu chromosome-level genome assembly (3.66 Gbp) and genome sequences for the extinct Yallara (lesser bilby, Macrotis leucura). We developed and tested a scat single-nucleotide polymorphism panel to inform current and future conservation actions, undertake ecological assessments and improve our understanding of Ninu genetic diversity in managed and wild populations. We also assessed the beneficial impact of translocations in the metapopulation (N = 363 Ninu). Resequenced genomes (temperate Ninu, 6; semi-arid Ninu, 6; and Yallara, 4) revealed two major population crashes during global cooling events for both species and differences in Ninu genes involved in anatomical and metabolic pathways. Despite their 45-year captive history, Ninu have fewer long runs of homozygosity than other larger mammals, which may be attributable to their boom-bust life history. Here we investigated the unique Ninu biology using 12 tissue transcriptomes revealing expression of all 115 conserved eutherian chorioallantoic placentation genes in the uterus, an XY 1 Y 2 sex chromosome system and olfactory receptor gene expansions. Together, we demonstrate the holistic value of genomics in improving key conservation actions, understanding unique biological traits and developing tools for Indigenous rangers to monitor remote wild populations., (© 2024. The Author(s).)

Antibodies perform both neutralizing and non-neutralizing effector functions that protect against certain pathogen-induced diseases. A human antibody directed at the SARS-CoV-2 Spike N-terminal domain (NTD), DH1052, was recently shown to be non-neutralizing, yet it protected mice and cynomolgus macaques from severe disease. The mechanisms of NTD non-neutralizing antibody-mediated protection are unknown. Here we show that Fc effector functions mediate NTD non-neutralizing antibody (non-nAb) protection against SARS-CoV-2 MA10 viral challenge in mice. Though non-nAb prophylactic infusion did not suppress infectious viral titers in the lung as potently as neutralizing antibody (nAb) infusion, disease markers including gross lung discoloration were similar in nAb and non-nAb groups. Fc functional knockout substitutions abolished non-nAb protection and increased viral titers in the nAb group. Fc enhancement increased non-nAb protection relative to WT, supporting a positive association between Fc functionality and degree of protection from SARS-CoV-2 infection. For therapeutic administration of antibodies, non-nAb effector functions contributed to virus suppression and lessening of lung discoloration, but the presence of neutralization was required for optimal protection from disease. This study demonstrates that non-nAbs can utilize Fc-mediated mechanisms to lower viral load and prevent lung damage due to coronavirus infection., Competing Interests: KOS, DL, and BFH have patents related to the antibodies described in this manuscript., (Copyright: © 2024 Pierre et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

A critical roadblock to HIV vaccine development is the inability to induce B cell lineages of broadly neutralizing antibodies (bnAbs) in humans. In people living with HIV-1, bnAbs take years to develop. The HVTN 133 clinical trial studied a peptide/liposome immunogen targeting B cell lineages of HIV-1 envelope (Env) membrane-proximal external region (MPER) bnAbs (NCT03934541). Here, we report MPER peptide-liposome induction of polyclonal HIV-1 B cell lineages of mature bnAbs and their precursors, the most potent of which neutralized 15% of global tier 2 HIV-1 strains and 35% of clade B strains with lineage initiation after the second immunization. Neutralization was enhanced by vaccine selection of improbable mutations that increased antibody binding to gp41 and lipids. This study demonstrates proof of concept for rapid vaccine induction of human B cell lineages with heterologous neutralizing activity and selection of antibody improbable mutations and outlines a path for successful HIV-1 vaccine development., Competing Interests: Declaration of interests B.F.H. and S.M.A. have US patents 9402917, 9402893, 9717789, and 10588960 and US patent application 63/540482. B.F.H., S.M.A., and B.K. have US patent 10076567. B.F.H. and K.O.S. have patent applications PCT/US2023/077677 and PCT/US2023/077686. C.B.F. has patents on PEGylated liposomes., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Plethysmography is employed in nonhuman primates (NHPs) to calculate respiratory minute volume and determine the exposure time required to deliver an aerosol at the target dose. Anesthetic drugs can impact breathing parameters like steady-state minute volume (SSMV) central to aerosol dosing. Alfaxalone-midazolam mixtures (AM) provide superior parameters for plethysmography in cynomolgus macaques. An obstacle to the use of AM is the volume required to anesthetize via intramuscular injection. A more concentrated formulation of alfaxalone will reduce injection volumes and refine AM protocols. The purpose of this study was to compare AM using the Indexed 10-mg/mL (AM10) formulation compared with an investigational 40-mg/mL (AM40) formulation for IM administration in cynomolgus macaques undergoing plethysmography. We hypothesized that AM10 and AM40 would show no difference in quality of anesthesia (QA), duration of anesthesia, SSMV, accumulated minute volume (AMV), and side effects. We also hypothesized that female macaques would have a longer duration of anesthesia compared with males using both formulations. The study used 15 cynomolgus macaques comprised of 8 females and 7 males. NHPs were compared between 2 separate and randomized anesthetic events no less than one week apart. Each animal served as its own control and animals were randomized by random number generation. Anesthetized NHPs were placed in a sealed plethysmography chamber, and minute volume measurements were calculated every 10 s to determine SSMV. Once SSMV was achieved for 20 min, the trial ended. There were no statistically significant differences between AM10 and AM40 for duration of anesthesia, SSMV, AMV, side effects, or QA. AM40 had a significantly smaller injection volume. Females did not show a significantly longer median duration of anesthesia using either of the alfaxalone formulations. Overall, AM40 offers a more humane anesthetic than AM10 for plethysmography in cynomolgus macaques.

Strategies to improve the scale-up of antiretroviral therapy (ART) for patients with HIV in Trinidad and Tobago, including the adoption of the "Test and Treat All" policy, have accompanied an increase in the number of patients with pretreatment HIV drug resistance (PDR) in the country. However, the scale of this public health problem is not well established. The objective of this study was to estimate the prevalence of PDR and evaluate its impact on viral suppression among patients with HIV receiving care at a large HIV treatment center in Trinidad and Tobago. We retrospectively analyzed data from the Medical Research Foundation of Trinidad and Tobago of patients newly diagnosed with HIV who had HIV genotyping performed. PDR was defined as having at least one drug-resistant mutation. We assessed the impact of PDR on achieving viral suppression within 12 months of ART initiation, using a Cox extended model. Among 99 patients, 31.3% had PDR to any drug, 29.3% to a non-nucleoside reverse transcriptase inhibitor (NNRTI), 3.0% to a nucleoside reverse transcriptase inhibitor, and 3.0% to a protease inhibitor. Overall, 67.1% of the patients who initiated ART ( n  = 82) and 66.7% (16/24) of patients with PDR achieved viral suppression within 12 months. We found no significant association between PDR status and achieving viral suppression within 12 months [adjusted hazard ratio: 1.08 (95% confidence interval: 0.57-2.04)]. There is a high prevalence of PDR in Trinidad and Tobago, specifically driven by NNRTI resistance. Although we found no difference in virologic suppression by PDR status, there is an urgent need for an effective HIV response to address the many drivers of virologic failure. Accelerating access to affordable, quality-assured generic dolutegravir and adopting it as the preferred first-line ART therapy are critical.

Many organisms can adjust their development according to environmental conditions, including the presence of conspecifics. Although this developmental plasticity is common in amphibians, its underlying molecular mechanisms remain largely unknown. Exposure during development to either 'cannibal cues' from older conspecifics, or 'alarm cues' from injured conspecifics, causes reduced growth and survival in cane toad ( Rhinella marina ) tadpoles. Epigenetic modifications, such as changes in DNA methylation patterns, are a plausible mechanism underlying these developmental plastic responses. Here we tested this hypothesis, and asked whether cannibal cues and alarm cues trigger the same DNA methylation changes in developing cane toads. We found that exposure to both cannibal cues and alarm cues was associated with local changes in DNA methylation patterns. These DNA methylation changes affected genes putatively involved in developmental processes, but in different genomic regions for different conspecific-derived cues. Genetic background explains most of the epigenetic variation among individuals. Overall, the molecular mechanisms triggered by exposure to cannibal cues seem to differ from those triggered by alarm cues. Studies linking epigenetic modifications to transcriptional activity are needed to clarify the proximate mechanisms that regulate developmental plasticity in cane toads., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)