Biology subjects

Prakash, A.

Publications and source records attributed to Prakash, A..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Class switching is differentially regulated in RBC alloimmunization and vaccination

BackgroundStudies of human patients have shown that most anti-RBC alloantibodies are IgG1 or IgG3 subclasses, though it is unclear why transfused RBCs preferentially drive these subclasses over others. Though mouse models allow for the mechanistic exploration of class-switching, previous studies of RBC alloimmunization in mice have focused more on the total IgG response than the relative distribution, abundance, or mechanism of IgG subclass generation. Given this major gap, we compared the IgG subclass distribution generated in response to transfused RBCs relative to protein in alum vaccination, and determined the role of STAT6 in their generation. Study Design and MethodsWT mice were either immunized with Alum/HEL-OVA or transfused with HOD RBCs and levels of anti-HEL IgG subtypes were measured using end-point dilution ELISAs. To study the role of STAT6 in IgG class-switching, we first generated and validated novel STAT6 KO mice using CRISPR/cas9 gene editing. STAT6 KO mice were then transfused with HOD RBCs or immunized with Alum/HEL-OVA, and IgG subclasses were quantified by ELISA. ResultsWhen compared to antibody responses to Alum/HEL-OVA, transfusion of HOD RBCs induced lower levels of IgG1, IgG2b and IgG2c but similar levels of IgG3. Class switching to most IgG subtypes remained largely unaffected in STAT6 deficient mice in response to HOD RBC transfusion, with the one exception being IgG2b. In contrast, STAT6 deficient mice showed altered levels of all IgG subtypes following Alum vaccination. DiscussionOur results show that anti-RBC class-switching occurs via alternate mechanisms when compared to the well-studied immunogen alum vaccination.

immunology↗

bioRxiv2022

Disruption of flour beetle microbiota limits experimentally evolved immune priming response, but not pathogen resistance

Host-associated microbiota play a fundamental role in the training and induction of different forms of immunity, including inducible as well as constitutive components. However, direct experiments analysing the relative importance of microbiota during evolution of different immune functions are missing. We addressed this gap by using experimentally evolved lines of Tribolium castaneum that either produced inducible immune memory-like responses (immune priming) or constitutively expressed basal resistance (without priming), as mutually exclusive strategies against Bacillus thuringiensis infection. We disrupted the microbial communities in these evolved lines and estimated the impact on the beetles ability to mount a priming response vs basal resistance. Populations that had evolved immune priming lost the ability to mount a priming response upon microbiota disruption. Microbiota manipulation also caused a drastic reduction in their reproductive output and post-infection longevity. In contrast, in pathogen-resistant beetles, microbiota manipulation did not affect post-infection survival or reproduction. The divergent evolution of immune responses across beetle lineages was thus associated with divergent reliance on the microbiome. Whether the latter is a direct outcome of differential pathogen exposure during selection or reflects evolved immune functions remains unclear. We hope that our results will motivate further experiments to understand the mechanistic basis of these complex evolutionary associations between microbiota, host immune strategies, and fitness outcomes.

evolutionary biology↗

bioRxiv2022

Lepidopteran prolegs are novel traits, not leg homologs

Lepidopteran larvae have both thoracic legs and abdominal prolegs, yet it is unclear whether these are serial homologs. We examined the role of three Hox genes in proleg development in Bicyclus anynana butterflies using CRISPR-Cas9 and discovered that under a partial segment abdominal-A (abd-A) knockout, both types of appendages can develop in the same segment, arguing for prolegs being a novel trait, not a leg serial homolog. We also discover that specificity protein (sp) genes do not co-localize with Distal-less (Dll) in prolegs, as they do in legs, and that the proleg gene-regulatory network (GRN) mostly resembles the head-horn GRN, another novel trait in the lepidoptera. We propose that larval prolegs evolved from the co-option of a partial limb GRN into novel embryonic coordinates in the abdomen. One-Sentence SummaryThe chubby legs of caterpillars are evolutionary innovations

evolutionary biology↗

bioRxiv2022

Ageing leads to nonspecific antimicrobial peptide responses in Drosophila melanogaster

Evolutionary theory predicts a late-life decline in the force of natural selection, possibly leading to late-life deregulations of the immune system. A potential outcome of such immune-deregulation is the inability to produce specific immunity against target pathogens. We tested this possibility by infecting multiple Drosophila melanogaster lines (with bacterial pathogens) across age-groups, where either individual or different combinations of Imd- and Toll-inducible antimicrobial peptides (AMPs) were deleted using CRISPR gene editing. We show a high degree of non-redundancy and pathogen-specificity of AMPs in young flies: in some cases, even a single AMP could confer complete resistance. In contrast, ageing led to a complete loss of such specificity, warranting the action of multiple AMPs across Imd- and Toll-pathways during infections. Moreover, use of diverse AMPs either had no survival benefits, or even accompanied survival costs post-infection. These features were also sexually dimorphic: females expressed a larger repertoire of AMPs than males, but extracted equivalent survival benefits. Finally, age-specific expansion of the AMP-pool was associated with downregulation of negative-regulators of the Imd-pathway and a potential damage to renal function, as features of poorly-regulated immunity, Overall, we could establish ageing as an important driver of nonspecific AMP responses, across sexes and bacterial infections.

immunology↗

bioRxiv2022

Adverse PFAS effects on mouse oocyte in vitro maturation are associated with carbon-chain length and inclusion of a sulfonate group

Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that are used in products such as non-stick cookware, stain-resistant coating, and food packaging. PFAS are characterized by their fluorinated carbon chains that make them hard to degrade and bioaccumulate in human and animals. Toxicological studies have shown PFAS toxic effects: cytotoxicity, immunotoxicity, neurotoxicity, and reproductive toxicity. Two major categories of PFAS are perfluoroalkyl carboxylic acid (PFCA) and perfluoroalkyl sulfonic acid (PFSA). In this study, we used a mouse-oocyte-in-vitro-maturation (IVM) system to study how the structures of PFAS, such as carbon-chain length and functional groups, determine their reproductive toxicity. We found the toxicity of PFAS is elevated with increasing carbon-chain length and the inclusion of the sulfonate group. Specifically, at 600 {micro}M, perfluorohexanesulfonic acid (PFHxS) and perfluorooctanesulfonic acid (PFOS) reduced the rates of both germinal vesicle breakdown (GVBD) and polar body extrusion (PBE) as well as induced the formation of relatively large polar bodies. However, the shorter PFSA, perfluorobutanesulfonic acid (PFBS), and all PFCA did not show similar adverse cytotoxicity. We further examined mitochondria and cytoskeleton, two essential factors for cell division, in PFOS- and PFHxS-treated oocytes. We found that 600 {micro}M PFHxS and PFOS exposure induced excess reactive oxygen species (ROS) and decreased mitochondrial membrane potential (MMP). Cytoskeleton analysis revealed that PFHxS and PFOS exposure induced chromosome misalignment, abnormal F-actin organization, elongated the spindle formation, and symmetric division in the treated oocytes. Together, our study provides new information on the structure-toxicity relationship of PFAS. SynopsisReproductive toxicity of PFAS, a group of persistent organic pollutants, is determined by their chemical structures.

pharmacology and toxicology↗

bioRxiv2022

Centrosome Amplification promotes cell invasion via cell-cell contact disruption and Rap-1 activation

Centrosome amplification (CA) is a prominent feature of human cancers linked to genomic instability and tumourigenesis in vivo. CA is observed as early as pre-malignant metaplasia, with CA incidence increasing as the disease progresses from dysplasia to neoplasia. However, the mechanistic contributions of CA to tumourigenesis (tumour architecture and remodelling) are poorly understood. Using non-tumourigenic breast cells (MCF10A), we demonstrate that CA induction (by CDK1 inhibition or PLK4 overexpression) alone increased both cell migration, invasion and Extracellular Matrix (ECM) remodeling. Mechanistically, CA induction activated small GTPase Rap-1. We demonstrated the key role of Rap-1 mediated signalling in CA induced tumourigenesis through Rap-1 inhibition (using GGTI-298) which blocked CA-induced migration, invasion and ECM attachment. CA induction in a long-term MCF10A cell culture system disrupted epithelial cell-cell junction integrity, via dysregulation of expression and subcellular localisation of cell junction proteins (ZO-1, Occludin, JAM-A & {beta}-catenin). At the ultrastructural level, CA significantly inhibited apical junctional complex formation, as visualized by transmission electron microscopy. CA induction in the luminal A breast cancer cell line MCF7 revealed similar trends in cell junction disruption. Furthermore, CA induction in MCF10A elevated expression of integrin {beta}-3, matrix metalloprotease MMP1 and MMP13 facilitating the observed ECM attachment, degradation and cell invasion phenotype. In vivo validation using a Chicken Embryo xenograft model, showed CA positive (CA+) MCF10A cells invaded into the chicken mesodermal layer, characterised by inflammatory cell infiltration and a marked focal reaction between chorioallantoic membrane and cell graft. This reaction was inhibited by pre-treatment of CA+ MCF10A cells with GGTI-298. Interestingly, in metastatic breast cancer cells with high levels of endogenous CA (triple negative cell line MDA-MB-231) inhibition of this CA-signalling pathway (using PLK4 inhibitor Centrinone B) abrogated their metastatic capacity in vitro. This demonstrates dual roles for CA signalling, for initiating and maintaining the CA-induced metastatic phenotype. Here, we demonstrated that CA induction in normal non-tumourigenic cells acts through Rap-1-dependent signaling to confer early pro-tumourigenic changes promoting tumour progression, mediated by ECM disruption, and altered cell-cell contacts. These insights reveal that in normal cells, CA induction alone (without additional pro-tumorigenic alterations) is sufficient to induce tumourigenesis and CA-mediated signaling supports a metastatic phenotype. StatementCentrosome amplification alone drives early tumourigenic change in normal breast epithelial cells

cell biology↗

bioRxiv2022

Genome-wide analysis of PTR/POT transporters in Candida species and their functional characterization in the newly emerged pathogen Candida auris

The PTR or proton-dependent oligopeptide transporter (POT) family exploits the inwardly directed proton motive force to facilitate the cellular uptake of di- and tripeptides. Interestingly, representatives from the family have shown efficacy in delivering peptide-based antifungal derivatives in certain Candida species. Given the increased incidences of fungal infections by Candida species and the associated escalating orders of resistance against frontline antifungals, peptide derivatives are attractive therapeutic options. In that direction, the identification and characterization of PTR transporters serve as an essential first step in the translation of peptide-based antifungals as next-gen therapeutics. Herein, we present a genome-wide inventory of the PTR transporters in five prominent Candida species. Our study identifies 2 PTR transporters each in C. albicans and C. dubliniensis, 1 in C. glabrata, 4 in C. parapsilosis, and 3 in C. auris. Notably, despite all representatives retaining the conserved features seen in the PTR family, there exist two distinct classes of PTR transporters that differ in terms of their sequence identities and membrane topology. Further, we also evaluated the contribution of each PTR protein of the newly emerged multidrug-resistant C. auris in di-/tripeptide uptake. Notably, deletion of the PTR transporters encoded by BNJ08_003830 and BNJ08_005124 led to a marked reduction in the transport capabilities of several tested di-/tripeptides. Besides, BNJ08_005124 deletion also resulted in increased resistance towards the peptide-nucleoside drug Nikkomycin Z, pointing towards its predominant role in the uptake mechanism. Altogether, the study provides an important template for future structure-function investigations of PTR transporters in Candida species.

microbiology↗

bioRxiv2022

Genomic landscape of the DHA1 family in the newly emerged pathogen Candida auris and mapping substrate repertoire of the prominent member CauMdr1

The last decade has witnessed the rise of extremely threatening healthcare-associated multidrug resistant non-albicans Candida (NAC) species, Candida auris. Thus, understanding the molecular basis of antifungal resistance has emerged as the single most important goal amongst the research community. Since besides target alterations, efflux mechanisms contribute maximally to antifungal resistance, it is imperative to investigate their contributions in this pathogen. Of note, within the Major Facilitator Superfamily (MFS) of efflux pumps, Drug/H+ antiporter family 1 (DHA1) has been established as a predominant contributor towards xenobiotic efflux. Our study provides a complete landscape of DHA1 transporters encoded in the genome of C. auris. This study identifies 14 DHA1 transporters encoded in the genome of the pathogen. We also construct deletion and heterologous overexpression strains for the most important DHA1 drug transporter, viz., CauMdr1 to map the spectrum of its substrates. While the knockout strain did not show any significant changes in the resistance patterns against the majority of the tested substrates, the ortholog when overexpressed in a minimal background S. cerevisiae strain, AD1-8u-, showed significant enhancement in the Minimum inhibitory concentrations (MICs) against a large panel of antifungal molecules. Altogether, the present study provides a comprehensive template for investigating the role of DHA1 members of C. auris in antifungal resistance mechanisms.

microbiology↗

bioRxiv2021

Integrated view and comparative analysis of baseline protein expression in mouse and rat tissues

The increasingly large amount of proteomics data in the public domain enables, among other applications, the combined analyses of datasets to create comparative protein expression maps covering different organisms and different biological conditions. Here we have reanalysed public proteomics datasets from mouse and rat tissues (14 and 9 datasets, respectively), to assess baseline protein abundance. Overall, the aggregated dataset contained 23 individual datasets, including a total of 211 samples coming from 34 different tissues across 14 organs, comprising 9 mouse and 3 rat strains, respectively. In all cases, we studied the distribution of canonical proteins between the different organs. The number of canonical proteins per dataset ranged from 273 (tendon) and 9,715 (liver) in mouse, and from 101 (tendon) and 6,130 (kidney) in rat. Then, we studied how protein abundances compared across different datasets and organs for both species. As a key point we carried out a comparative analysis of protein expression between mouse, rat and human tissues. We observed a high level of correlation of protein expression among orthologs between all three species in brain, kidney, heart and liver samples, whereas the correlation of protein expression was generally slightly lower between organs within the same species. Protein expression results have been integrated into the resource Expression Atlas for widespread dissemination. Author summaryWe have reanalysed 23 baseline mass spectrometry-based public proteomics datasets stored in the PRIDE database. Overall, the aggregated dataset contained 211 samples, coming from 34 different tissues across 14 organs, comprising 9 mouse and 3 rat strains, respectively. We analysed the distribution of protein expression across organs in both species. We also studied how protein abundances compared across different datasets and organs for both species. Then we performed gene ontology and pathway enrichment analyses to identify enriched biological processes and pathways across organs. We also carried out a comparative analysis of baseline protein expression across mouse, rat and human tissues, observing a high level of expression correlation among orthologs in all three species, in brain, kidney, heart and liver samples. To disseminate these findings, we have integrated the protein expression results into the resource Expression Atlas.

bioinformatics↗

bioRxiv2021

A Method for Computationally Constructing Eukaryotic Synthetic Signal Peptide Sequences

We developed a computational method for constructing synthetic signal peptides from a base set of signal peptides (SPs) and non-SP sequences. A large number of structured "building blocks", represented as m-step ordered pairs of amino acids, are extracted from the base. Using a straightforward procedure, the building blocks enable the construction of a diverse set of synthetic SPs that could be utilized for industrial and therapeutic purposes. We have validated the proposed methodology using existing sequence prediction platforms such as Signal-BLAST and MULocDeep. In one experiment, 9,555 protein sequences were generated from a large randomly selected set of "building blocks". Signal-BLAST identified 8,444 (88%) of the sequences as signal peptides. In addition, the Signal-BLAST tool predicted that the generated synthetic sequences belonged to 854 distinct eukaryotic organisms. Here, we provide detailed descriptions and results from various experiments illustrating the potential usefulness of the methodology in generating signal peptide protein sequences.

bioinformatics↗

bioRxiv2021

Antennapedia regulates metallic silver wing scale development and cell shape in Bicyclus anynana butterflies

Butterfly wing scale cells can develop very intricate cuticular nanostructures that interact with light to produce structural colors including silvery hues, but the genetic basis of such nanostructures is mostly unexplored. Here, we first identified that optix is necessary for metallic scale development in the butterfly Bicyclus anynana. We then characterized different subtypes of wildtype metallic silver scales and addressed the function of five genes - apterous A, Ultrabithorax, doublesex, Antennapedia, and optix - in the differentiation of silver scales, at a single-cell resolution, by leveraging crispants that exhibited either ectopic gains or losses of silver scales. Wildtype silver scales were generally rounded and had low amounts of pigmentation, exhibiting a common ultrastructural modification for metallic broadband reflectance, i.e., an undulatory air layer enclosed by an upper and lower lamina. Our results indicated that the varying air layer thickness was the important parameter of the bilaminate scale for producing a broadband reflectance across visible wavelengths. While a single lamina of the appropriate thickness could also produce broadband colors, the bilaminate structure is advantageous as it increases the overall reflectivity. Crispant brown scales differed from wildtype silver scales via the loss of the continuous upper lamina, increased lower lamina thickness, and increased pigmentation. The reverse was seen when brown scales became silver. We identified Antennapedia and optix as high-level regulators in the network differentiating different silver scale subtypes and determining overall cell shape in both sexes. In addition, Antp exhibits a novel, post-embryonic role in the determination of ridge and crossrib orientation.

developmental biology↗

bioRxiv2021

Mechanisms of damage prevention, signalling, and repair impact the ability of Drosophila to tolerate enteric bacterial infection

The insect gut is frequently exposed to pathogenic threats and must not only clear these potential infections, but also tolerate relatively high microbe loads. In contrast to the mechanisms that eliminate pathogens, we currently know less about the mechanisms of disease tolerance. We investigated how well-described mechanisms that either prevent, signal, control, or repair damage during infection contribute to the phenotype of disease tolerance. We established enteric infections with the bacterial pathogen Pseudomonas entomophila in transgenic lines of Drosophila melanogaster fruit flies affecting dcy (a major component of the peritrophic matrix), upd3 (a cytokine-like molecule), irc (a negative regulator of reactive oxygen species) and egfr1 (epithelial growth factor receptor). Flies lacking dcy experienced the highest susceptibility, while loss of function of either irc or upd3 reduced tolerance in both sexes. The disruption of egfr1 resulted in a severe loss in tolerance in male flies but had no substantial effect on the ability of female flies to tolerate P. entomophila infection, despite carrying greater microbe loads than males. Together, our findings provide evidence for the role of damage limitation mechanisms in disease tolerance and highlight how sex differences in these mechanisms could generate sexual dimorphism in disease tolerance.

evolutionary biology↗

bioRxiv2021

Negative regulation of IMD contributes to disease tolerance during systemic bacterial infection in Drosophila

Disease tolerance is an infection phenotype where hosts show relatively high health despite harbouring elevated pathogen loads. Variation in the ability to reduce immunopathology may explain why some hosts can tolerate higher pathogen burdens with reduced pathology. Negative immune regulation would therefore appear to be a clear candidate for a mechanism underlying disease tolerance. Here, we examined how the negative regulation of the immune deficiency (IMD) pathway affects disease tolerance in Drosophila melanogaster when infected with four doses of the gram-negative bacterial pathogen Pseudomonas entomophila. We find that while flies unable to regulate the IMD response exhibited higher expression of antimicrobial peptides and lower bacterial loads as expected, this was not accompanied by a proportional reduction in mortality. Instead, UAS-RNAi knockdown of negative regulators of IMD (pirk and caudal) substantially increased the per-pathogen-mortality in both males and females across all tested infectious doses. Our results therefore highlight that in addition to regulating an efficient pathogen clearance response, negative regulators of IMD also contribute to disease tolerance.

evolutionary biology↗

bioRxiv2021

The Jak/Stat pathway mediates disease tolerance during systemic bacterial infection in Drosophila

Disease tolerance describes an infected hosts ability to maintain health independently of the ability to clear microbe loads. The Jak/Stat pathway plays a pivotal role in humoral innate immunity by detecting tissue damage and triggering cellular renewal, making it a candidate tolerance mechanism. Here, we find that in Drosophila melanogaster infected with Pseudomonas entomophila disrupting ROS-producing dual oxidase (duox) or the negative regulator of Jak/Stat Socs36E, render male flies less tolerant. Another negative regulator of Jak/Stat, G9a - which has previously been associated with variable tolerance of viral infections - did not affect the rate of mortality with increasing microbe loads compared to flies with functional G9a, suggesting it does not affect tolerance of bacterial infection as in viral infection. Our findings highlight that ROS production and Jak/Stat signalling influence the ability of flies to tolerate bacterial infection sex-specifically and may therefore contribute to sexually dimorphic infection outcomes in Drosophila.

evolutionary biology↗

bioRxiv2021

An integrated view of baseline protein expression in human tissues

The availability of proteomics datasets in the public domain, and in the PRIDE database in particular, has increased dramatically in recent years. This unprecedented large-scale availability of data provides an opportunity for combined analyses of datasets to get organism-wide protein abundance data in a consistent manner. We have reanalysed 24 public proteomics datasets from healthy human individuals, to assess baseline protein abundance in 31 organs. We defined tissue as a distinct functional or structural region within an organ. Overall, the aggregated dataset contains 67 healthy tissues, corresponding to 3,119 mass spectrometry runs covering 498 samples, coming from 489 individuals. We compared protein abundances between the different organs and studied the distribution of proteins across organs. We also compared the results with data generated in analogous studies. We also performed gene ontology and pathway enrichment analyses to identify organ-specific enriched biological processes and pathways. As a key point, we have integrated the protein abundance results into the resource Expression Atlas, where it can be accessed and visualised either individually or together with gene expression data coming from transcriptomics datasets. We believe this is a good mechanism to make proteomics data more accessible for life scientists.

bioinformatics↗

bioRxiv2021

Free spermidine evokes superoxide radicals that manifest toxicity

Spermidine and other polyamines alleviate oxidative stress, yet excess spermidine seems toxic to Escherichia coli unless it is neutralized by SpeG, an enzyme for the spermidine N-acetyl transferase function. Besides, a specific mechanism of SpeG function conferring pathogenic fitness to Staphylococcus aureus USA300 strain is unknown. Here, we provide evidence that although spermidine mitigates oxidative stress by lowering hydroxyl radical and hydrogen peroxide levels, excess of it simultaneously triggers the production of superoxide radicals, thereby causing toxicity in the E. coli {Delta}speG strain as well as naturally SpeG-deficient S. aureus RN4220 strain. However, wild-type E. coli and S. aureus USA300 with a horizontally-acquired speG gene tolerate applied exogenous spermidine stress. Furthermore, we demonstrate that while RNA-bound spermidine inhibits iron oxidation, free spermidine interacts and oxidizes the iron to evoke superoxide radicals directly. Superoxide radicals thus generated, further affects redox balance and iron homeostasis. Since iron acquisition and metabolism in the host tissues is a challenging task for S. aureus, the current findings helped us explain that the evolutionary gain of SpeG function by S. aureus USA300 strain allows it to neutralize exogenous spermidine- and spermine-mediated toxicity towards iron metabolism inside the host tissues.

biochemistry↗

bioRxiv2021

Conserved roles of Distal-less and spalt in regulating butterfly melanic patterns

Two genes, Distal-less (Dll) and spalt (sal), are known to be involved in establishing nymphalid butterfly wing patterns. They function in several ways: in the differentiation of the eyespots central signaling cells, or foci; in the differentiation of the surrounding black disc; in overall scale melanisation (Dll); and in elaborating marginal patterns, such as parafocal elements. However, little is known about the functions of these genes in the development of wing patterns in other butterfly families. Here, we study the expression and function of Dll and sal in the development of spots and other melanic wing patterns of the Indian cabbage white, Pieris canidia, a pierid butterfly. In P. canidia, both Dll and Sal proteins are expressed in the scale-building cells at the wing tips, in chevron patterns along the pupal wing margins, and in areas of future scale melanisation. Additionally, Sal alone is expressed in the future black spots. CRISPR knockouts of Dll and sal showed that each gene is required for the development of melanic wing pattern elements, and repressing pteridine granule formation, in the areas where they are expressed. We conclude that both genes likely play ancestral roles in organising distal butterfly wing patterns, across pierid and nymphalid butterflies, but are unlikely to be differentiating signalling centers in pierids black spots. The genetic and developmental mechanisms that set up the location of spots and eyespots are likely distinct in each lineage.

evolutionary biology↗

bioRxiv2021

Captivity-induced behaviour and spatial learning abilities in an enigmatic, aquifer-dwelling blind eel, Rakthamichthys digressus

We investigated the impact of captive life on behaviour and learning abilities in an enigmatic, aquifer-dwelling blind eel, Rakthamichthys digressus. Of eight major behavioural traits related to exploration and activity in a novel arena, four were significantly altered by life in captivity. While the startle response upon introduction into the arena and overall swimming away from the walls increased after captivity, inactivity exhibited immediately after the startle and the reaction to an external disturbance decreased. We also observed behavioural syndromes between startle responses and horizontal wall following, and between overall activity and vertical wall following; however, these behavioural syndromes were not altered by maintenance in captivity. Interestingly, this blind-eel failed to learn a simple spatial task in a Y-maze apparatus. Captive-associated behavioural changes in R. digressus may influence their survival after reintroduction into natural habitats, and such changes must be taken into account while developing protocols for ex-situ conservation and subsequent release.

animal behavior and cognition↗