Non-mammalian Species Research Articles

Endocannabinoid System and Metabolism: The Influences of Sex

The endocannabinoid system (ECS) is a lipid signaling system involved in numerous physiological processes, such as endocrine homeostasis, appetite control, energy balance, and metabolism. The ECS comprises endocannabinoids, their cognate receptors, and the enzymatic machinery that tightly regulates their levels within tissues. This system has been identified in various organs, including the brain and liver, in multiple mammalian and non-mammalian species. However, information regarding the sex-specific regulation of the ECS remains limited, even though increasing evidence suggests that interactions between sex steroid hormones and the ECS may ultimately modulate hepatic metabolism and energy homeostasis. Within this framework, we will review the sexual dimorphism of the ECS in various animal models, providing evidence of the crosstalk between endocannabinoids and sex hormones via different metabolic pathways. Additionally, we will underscore the importance of understanding how endocrine-disrupting chemicals and exogenous cannabinoids influence ECS-dependent metabolic pathways in a sex-specific manner.

Hepatic enzyme induction and its potential effect on thyroid hormone metabolism in the metamorphosing tadpole of Xenopus laevis (African clawed frog).

Hepatic enzyme induction, an inherent defense system against xenobiotics, is known to simultaneously affect endocrine system functions in mammals under specific conditions, particularly thyroid hormone (TH) regulation. While this phenomenon has been studied extensively, the pathway leading to this indirect thyroid effect in mammals has unclear applicability to amphibians, despite the importance of amphibian species in assessing thyroid-disruptive chemicals. Here, we investigated the effects of three well-known mammalian enzyme inducers-β-naphthoflavone (BNF), pregnenolone carbonitrile (PCN), and sodium phenobarbital (NaPB)-on the gene expression of phase-I and phase-II metabolizing enzymes in Xenopus laevis tadpoles. Waterborne exposure to BNF and PCN significantly induced the expression of both phase-I (cytochrome P450, CYP) and phase-II enzymes (UDP-glucuronosyltransferase, UGT and sulfotransferase, SULT), but in different patterns, while NaPB exposure induced CYP2B expression without affecting phase-II enzymes in tadpoles, in contrast to mammals. Furthermore, an ex vivo hepatic enzyme activity assay confirmed that BNF treatment significantly increased phase-II metabolic activity (glucuronidation and sulfation) toward TH. These results suggest the potential for certain mammalian enzyme inducers to influence TH clearance in X. laevis tadpoles. Our findings provide insights into the profiles of xenosensing activity and enzyme induction in amphibians, which can facilitate a better understanding of the mechanisms of indirect effects on the thyroid system via hepatic enzyme induction in nonmammalian species.

Modeling Trophic Cascades to Identify Key Mammalian Species for Ecosystem Stability

The role of keystone species in maintaining ecosystem stability is a crucial aspect of ecology. Identifying key mammalian species within an ecosystem requires a systematic approach, utilizing criteria and indicators derived from species characteristic variables. This study presents a framework to identify key mammalian species based on various ecological, structural, and functional factors. By developing a mechanistic model of energy flow in food webs and trophic levels, the model aims to pinpoint each species’ role in the stability and sustainability of biomass flow within the ecosystem. Known as KVT version 1.0, the model explains the role of each characteristic variable of mammalian species, predicts population growth, elucidates species interactions at trophic levels, and assesses species-specific dietary compositions, including food requirements, reproduction, and activity. Factor analysis of model outputs has produced equations to determine the value of keystone species (Kv), indicating the role of mammalian species in the stability and sustainability of biomass flow in the ecosystem. Keystone species, as identified by this model, are primarily small mammals of the families Muridae, Sciuridae, Tupaiidae, Ptilocercidae, Hystricidae, Viverridae, and Herpestidae, demonstrating omnivorous and herbivorous trophic levels. This model can serve as a valuable framework for conservation management of biodiversity in an ecosystem, with potential for expansion to include characteristics of non-mammalian species in future research.

Inhibiting p38α and β MAPK affects testis development in the marsupial tammar wallaby.

The MAPK genes are critical for gonadal differentiation in eutherian mammals but their role in marsupial mammals is unknown. Characterisation and phylogenetic analyses of the tammar wallaby MAPK genes shows these genes are highly conserved with their orthologues in mammalian and non-mammalian species. We cultured sexually indifferent tammar gonads in the presence of p38α and β MAPK inhibitor, SB202190. SB202190 downregulated SOX9 and AMH levels in XY treated gonads when compared to controls, similar to the effects of oestrogen on the MAPK pathway in males. In contrast, XX gonads treated with the SB202190 inhibitor showed no change in mRNA expression between the control and treated gonads for any of the markers tested. This study confirms that components of the MAPK pathway drive testis differentiation via the key downstream genes SOX9 and AMH in marsupials as is observed in eutherian mammals.

Monoallelic de novo variants in DDX17 cause a neurodevelopmental disorder.

DDX17 is an RNA helicase shown to be involved in critical processes during the early phases of neuronal differentiation. Globally, we compiled a case-series of 11 patients with neurodevelopmental phenotypes harbouring de novo monoallelic variants in DDX17. All 11 patients in our case series had a neurodevelopmental phenotype, whereby intellectual disability, delayed speech and language, and motor delay predominated. We performed in utero cortical electroporation in the brain of developing mice, assessing axon complexity and outgrowth of electroporated neurons, comparing wild-type and Ddx17 knockdown. We then undertook ex vivo cortical electroporation on neuronal progenitors to quantitatively assess axonal development at a single cell resolution. Mosaic ddx17 crispants and heterozygous knockouts in Xenopus tropicalis were generated for assessment of morphology, behavioural assays, and neuronal outgrowth measurements. We further undertook transcriptomic analysis of neuroblastoma SH-SY5Y cells, to identify differentially expressed genes in DDX17-KD cells compared to controls. Knockdown of Ddx17 in electroporated mouse neurons in vivo showed delayed neuronal migration as well as decreased cortical axon complexity. Mouse primary cortical neurons revealed reduced axon outgrowth upon knockdown of Ddx17 in vitro. The axon outgrowth phenotype was replicated in crispant ddx17 tadpoles and in heterozygotes. Heterozygous tadpoles had clear neurodevelopmental defects and showed an impaired neurobehavioral phenotype. Transcriptomic analysis identified a statistically significant number of differentially expressed genes involved in neurodevelopmental processes in DDX17-KD cells compared to control cells. We have identified potential neurodevelopment disease-causing variants in a gene not previously associated with genetic disease, DDX17. We provide evidence for the role of the gene in neurodevelopment in both mammalian and non-mammalian species and in controlling the expression of key neurodevelopment genes.

Neuroinflammation as a cause of differential Müller cell regenerative responses to retinal injury.

Unlike mammals, some nonmammalian species recruit Müller glia for retinal regeneration after injury. Identifying the underlying mechanisms may help to foresee regenerative medicine strategies. Using a Xenopus model of retinitis pigmentosa, we found that Müller cells actively proliferate upon photoreceptor degeneration in old tadpoles but not in younger ones. Differences in the inflammatory microenvironment emerged as an explanation for such stage dependency. Functional analyses revealed that enhancing neuroinflammation is sufficient to trigger Müller cell proliferation, not only in young tadpoles but also in mice. In addition, we showed that microglia are absolutely required for the response of mouse Müller cells to mitogenic factors while negatively affecting their neurogenic potential. However, both cell cycle reentry and neurogenic gene expression are allowed when applying sequential pro- and anti-inflammatory treatments. This reveals that inflammation benefits Müller glia proliferation in both regenerative and nonregenerative vertebrates and highlights the importance of sequential inflammatory modulation to create a regenerative permissive microenvironment.

Photoneuroendocrine, circadian and seasonal systems: from photoneuroendocrinology to circadian biology and medicine.

This contribution highlights the scientific development of two intertwined disciplines, photoneuroendocrinology and circadian biology. Photoneuroendocrinology has focused on nonvisual photoreceptors that translate light stimuli into neuroendocrine signals and serve rhythm entrainment. Nonvisual photoreceptors first described in the pineal complex and brain of nonmammalian species are luminance detectors. In the pineal, they control the formation of melatonin, the highly conserved hormone of darkness which is synthesized night by night. Pinealocytes endowed with both photoreceptive and neuroendocrine capacities function as "photoneuroendocrine cells." In adult mammals, nonvisual photoreceptors controlling pineal melatonin biosynthesis and pupillary reflexes are absent from the pineal and brain and occur only in the inner layer of the retina. Encephalic photoreceptors regulate seasonal rhythms, such as the reproductive cycle. They are concentrated in circumventricular organs, the lateral septal organ and the paraventricular organ, and represent cerebrospinal fluid contacting neurons. Nonvisual photoreceptors employ different photopigments such as melanopsin, pinopsin, parapinopsin, neuropsin, and vertebrate ancient opsin. After identification of clock genes and molecular clockwork, circadian biology became cutting-edge research with a focus on rhythm generation. Molecular clockworks tick in every nucleated cell and, as shown in mammals, they drive the expression of more than 3000 genes and are of overall importance for regulation of cell proliferation and metabolism. The mammalian circadian system is hierarchically organized; the central rhythm generator is located in the suprachiasmatic nuclei which entrain peripheral circadian oscillators via multiple neuronal and neuroendocrine pathways. Disrupted molecular clockworks may cause various diseases, and investigations of this interplay will establish a new discipline: circadian medicine.

Proteome asymmetry in mouse and human embryos before fate specification.

Pre-patterning of the embryo, driven by spatially localized factors, is a common feature across several non-mammalian species 1-4 . However, mammals display regulative development and thus it was thought that blastomeres of the embryo do not show such pre-patterning, contributing randomly to the three lineages of the blastocyst: the epiblast, primitive endoderm and trophectoderm that will generate the new organism, the yolk sac and placenta respectively 4-6 . Unexpectedly, early blastomeres of mouse and human embryos have been reported to have distinct developmental fates, potential and heterogeneous abundance of certain transcripts 7-12 . Nevertheless, the extent of the earliest intra-embryo differences remains unclear and controversial. Here, by utilizing multiplexed and label-free single-cell proteomics by mass-spectrometry 13 , we show that 2-cell mouse and human embryos contain an alpha and a beta blastomere as defined by differential abundance of hundreds of proteins exhibiting strong functional enrichment for protein synthesis, transport, and degradation. Such asymmetrically distributed proteins include Gps1 and Nedd8, depletion or overexpression of which in one blastomere of the 2-cell embryo impacts lineage segregation. These protein asymmetries increase at 4-cell stage. Intriguingly, halved mouse zygotes display asymmetric protein abundance that resembles alpha and beta blastomeres, suggesting differential proteome localization already within zygotes. We find that beta blastomeres give rise to a blastocyst with a higher proportion of epiblast cells than alpha blastomeres and that vegetal blastomeres, which are known to have a reduced developmental potential, are more likely to be alpha. Human 2-cell blastomeres also partition into two clusters sharing strong concordance with clusters found in mouse, in terms of differentially abundant proteins and functional enrichment. To our knowledge, this is the first demonstration of intra-zygotic and inter-blastomere proteomic asymmetry in mammals that has a role in lineage segregation.

Playtime for Cephalopods: Understanding the Significance of Play Behavior in Octopus bimaculoides.

Play is considered to be an essential part of development that supports learning, memory, and the development of flexible behavioral strategies. An increasing amount of non-mammalian species have been discovered to engage in play behavior, but there has been little research into play behavior in cephalopods specifically. Here we studied play behavior of wild-caught, laboratory-housed California Two-Spot Octopuses, Octopus bimaculoides. The behavior observed in these animals is consistent with established criteria of play behavior in animals. The evidence of play in O. bimaculoides provides further insight into the evolutionary development of play behavior as a whole, the characteristics of play in an under-studied species, and also has the potential to be used as a factor in determining the welfare state of octopuses to improve their management in captivity.

Turbinal bones are still one of the last frontiers of the tetrapod skull: hypotheses, challenges and perspectives.

Turbinals are bony or cartilaginous structures that are present in the nasal cavity of most tetrapods. They are involved in key functions such as olfaction, heat, and moisture conservation, as well as protection of the respiratory tract. Despite recent studies that challenged long-standing hypotheses about their physiological and genomic correlation, turbinals remain largely unexplored, particularly for non-mammalian species. Herein, we review and synthesise the current knowledge of turbinals using an integrative approach that includes comparative anatomy, physiology, histology and genomics. In addition, we provide synonyms and correspondences of tetrapod turbinals from about 80 publications. This work represents a first step towards drawing hypotheses of homology for the whole clade, and provides a strong basis to develop new research avenues.

Activin Signaling Pathway Specialization During Embryonic and Skeletal Muscle Development in Rainbow Trout (Oncorhynchus mykiss).

Activin signaling is essential for proper embryonic, skeletal muscle, and reproductive development. Duplication of the pathway in teleost fish has enabled diversification of gene function across the pathway but how gene duplication influences the function of activin signaling in non-mammalian species is poorly understood. Full characterization of activin receptor signaling pathway expression was performed across embryonic development and during early skeletal muscle growth in rainbow trout (RBT, Oncorhynchus mykiss). Rainbow trout are a model salmonid species that have undergone two additional rounds of whole genome duplication. A small number of genes were expressed early in development and most genes increased expression throughout development. There was limited expression of activin Ab in RBT embryos despite these genes exhibiting significantly elevated expression in post-hatch skeletal muscle. CRISPR editing of the activin Aa1 ohnolog and subsequent production of meiotic gynogenetic offspring revealed that biallelic disruption of activin Aa1 did not result in developmental defects, as occurs with knockout of activin A in mammals. The majority of gynogenetic offspring exhibited homozygous activin Aa1 genotypes (wild type, in-frame, or frameshift) derived from the mosaic founder female. The research identifies mechanisms of specialization among the duplicated activin ohnologs across embryonic development and during periods of high muscle growth in larval and juvenile fish. The knowledge gained provides insights into potential viable gene-targeting approaches for engineering the activin receptor signaling pathway and establishes the feasibility of employing meiotic gynogenesis as a tool for producing homozygous F1 genome-edited fish for species with long-generation times, such as salmonids.

Assessment of visual acuity in Python regius using optokinetic response.

Snakes are known for their unique abilities including infrared reception and their heavy reliance on heat sensors and vibrations. Infrared reception of snakes has gone under immense investigation; however, there have been very few studies that elaborate on their capacity to see. The goal of this study is to determine visual acuity of ball pythons (Python regius) by observing their optokinetic response (OKR). The OKR is a series of rapid saccadic and smooth pursuit movements of the eyes. It has been used for decades to determine visual acuity in multiple species such as humans, rats, and other nonmammalian species such as zebrafish and box turtles. Past studies have discovered that birds, reptiles, and amphibians achieve gaze stabilization by head and body movements, whereas in mammals and fish, gaze stabilization is conducted by eye movements. In this study, ball pythons were placed in a clear tube in a dark room, and a spinning black and white grating was projected in front of them. The size, direction, and velocity of the grating was manipulated which allowed their visual acuity to be determined. Our hypothesis is that P. regius would have a poor OKR response with low visual acuity due to their heavy reliance on other senses. Results show that P. regius does respond to visual stimuli, shows ocular saccadic movement in the direction of their stimuli, and has a relatively poor visual acuity when compared to other previously studied reptiles.

O-171 Apicobasal RNA asymmetries regulate cell fate in the early mouse embryo

Abstract Assessing the morphological appearance of an embryo as it progresses from zygote to blastocyst is the primary method used by embryologists to evaluate embryo viability and developmental potential. Standard embryo grading techniques, using time-lapse microscopy, analyse morphological characteristics such as size, shape, number, and appearance of blastomeres. The aim of this study was to determine how individual cells of the embryo function on a subcellular level to build a healthy embryo. RNA localisation plays indispensable roles in establishing asymmetries and coordinating cell fate decisions during early embryogenesis across various non-mammalian species. To direct the spatiotemporal distribution of RNA within the cells of an embryo, the microtubule cytoskeleton provides highly sophisticated trafficking pathways. Yet, it remains unknown whether subcellular heterogeneities exist during mammalian preimplantation development and how they contribute to cell fate determination. Using advanced live imaging, we visualised global RNA transcripts at high spatiotemporal resolution from fertilisation to the blastocyst stage in living preimplantation mouse embryos. We discovered apicobasal RNA asymmetries specific to outer cells of the 16-cell stage mouse embryo, coinciding with cell fate decisions and the emergence of the pluripotent inner cell mass. Highly clustered RNAs accumulated proximal to the basal membrane, while more dispersed RNA foci were identified apically as the embryo reaches the late 16-cell stage. The targeted distribution of membrane-less RNA molecules was facilitated by the microtubule cytoskeleton, associated with lysosomes which serve as RNA transport vehicles. We discovered that apically located RNA foci were more dynamic and accompanied an enrichment of translation components. Furthermore, we uncovered that the established RNA asymmetries enhanced translation capacity in apical regions compared to basal regions. These spatiotemporal RNA heterogeneities were unevenly inherited by outer and inner daughter cells during subsequent cell divisions. Notably, embryos that were unable to establish RNA asymmetries failed to allocate cells to the trophectoderm and inner cell mass. Our study provides insights into a subcellular mechanism driving asymmetric RNA localisation and compartmentalised translational regulation in outer cells of the 16-cell stage embryo, which may contribute to cell fate decisions during mammalian preimplantation embryogenesis. We envision that when paired with classical morphological assessment criteria of the embryo, these findings may assist with selecting the embryo with the highest developmental potential.

Gene Expression Level and Immunohistochemical Localization of Cannabinoid and Cannabinoid-Related Receptors in The Small Intestine of Holstein Bulls (Bos Taurus Taurus)

Abstract The gastrointestinal tract plays a crucial role in nutrient absorption, secretion, and motility, ensuring proper digestion and overall homeostasis. Regulation of this complex system involves the coordination of various communication pathways, including neural and humoral mechanisms. One such mechanism is the endocannabinoid system (ECS), a signaling network comprising endogenous cannabinoids, receptors, and enzymes involved in the regulation of physiological processes in mammals and non-mammalian species. While extensive research has been conducted on the ECS in monogastric animals, limited information is available on its presence and distribution in cattle. This study aimed to investigate the distribution and localization patterns of cannabinoid receptors type 1 (CB1R) and type 2 (CB2R) and transient receptor potential vanilloid type 1 (TRPV1) in the bovine small intestine. The study included immunohistochemical analysis of intestinal tissue samples from Polish Holstein-Friesian breed bulls. Gene expression levels of CNR1, CNR2, and TRPV1 genes, encoding CB1R, CB2R, and TRPV1, respectively, were quantified using qPCR analysis. The results showed that all three receptors were expressed in the bovine small intestine, with TRPV1 exhibiting a significant upregulation in the jejunum compared to the duodenum and ileum. Immunoreactivity for CB1R and CB2R was predominantly observed in neurons of the enteric plexuses, while TRPV1 immunolabeling was detected in both enteric neurons and duodenal Brunner’s glands. These findings may establish an anatomical foundation for further investigations, lending support to the potential therapeutic efficacy of cannabinoid receptor agonists in alleviating gastrointestinal motility disorders associated with bovine enteropathies and optimizing milk production in dairy cattle.

Origins of mammalian vertebral function revealed through digital bending experiments.

Unravelling the functional steps that underlie major transitions in the fossil record is a significant challenge for biologists owing to the difficulties of interpreting functional capabilities of extinct organisms. New computational modelling approaches provide exciting avenues for testing function in the fossil record. Here, we conduct digital bending experiments to reconstruct vertebral function in non-mammalian synapsids, the extinct forerunners of mammals, to provide insights into the functional underpinnings of the synapsid-mammal transition. We estimate range of motion and stiffness of intervertebral joints in eight non-mammalian synapsid species alongside a comparative sample of extant tetrapods, including salamanders, reptiles and mammals. We show that several key aspects of mammalian vertebral function evolved outside crown Mammalia. Compared to early diverging non-mammalian synapsids, cynodonts stabilized the posterior trunk against lateroflexion, while evolving axial rotation in the anterior trunk. This was later accompanied by posterior sagittal bending in crown mammals, and perhaps even therians specifically. Our data also support the prior hypothesis that functional diversification of the mammalian trunk occurred via co-option of existing morphological regions in response to changing selective demands. Thus, multiple functional and evolutionary steps underlie the origin of remarkable complexity in the mammalian backbone.

Prostate Cancer-Specific Lysine 53 Acetylation of Cytochrome c Drives Metabolic Reprogramming and Protects from Apoptosis in Intact Cells.

Cytochrome c (Cytc) is important for both mitochondrial respiration and apoptosis, both of which are altered in cancer cells that switch to Warburg metabolism and manage to evade apoptosis. We earlier reported that lysine 53 (K53) of Cytc is acetylated in prostate cancer. K53 is conserved in mammals that is known to be essential for binding to cytochrome c oxidase and apoptosis protease activating factor-1 (Apaf-1). Here we report the effects of this acetylation on the main functions of cytochrome c by expressing acetylmimetic K53Q in cytochrome c double knockout cells. Other cytochrome c variants analyzed were wild-type, K53R as a control that maintains the positive charge, and K53I, which is present in some non-mammalian species. Intact cells expressing K53Q cytochrome c showed 49% decreased mitochondrial respiration and a concomitant increase in glycolytic activity (Warburg effect). Furthermore, mitochondrial membrane potential was decreased, correlating with notably reduced basal mitochondrial superoxide levels and decreased cell death upon challenge with H2O2 or staurosporine. To test for markers of cancer aggressiveness and invasiveness, cells were grown in 3D spheroid culture. K53Q cytochrome c-expressing cells showed profoundly increased protrusions compared to WT, suggesting increased invasiveness. We propose that K53 acetylation of cytochrome c is an adaptive response that mediates prostate cancer metabolic reprogramming and evasion of apoptosis, which are two hallmarks of cancer, to better promote tumor survival and metastasis.

DEVELOPING A THROMBOELASTOGRAPHY ASSAY IN ELASMOBRANCHS.

Thromboelastography (TEG) is a hemostatic assay evaluating clot initiation time, kinetics, strength, and extent of fibrinolysis. Hemostatic assays in nonmammalian species have been less extensively studied because of lack of taxon-specific reagents and unique physiology. Hemostatic or hemorrhagic disease has been described postmortem in elasmobranchs, but antemortem detection of coagulopathies is limited in this taxon. The study aimed to establish an elasmobranch TEG protocol to improve hemostatic evaluation and facilitate advanced treatment options for animals under human care. Multiple clotting initiators were assessed for efficacy with frozen-thawed citrated plasma, fresh citrated plasma, and fresh whole citrated blood: RapidTEGTM, citrated kaolin, Reptilase®, and species brain-derived thromboplastin prepared by two different methods. Initial evaluation found plasma samples clot inconsistently, but TEG analyses using fresh whole blood consistently led to measurable TEG reactions using multiple clotting initiators. The most reliable elasmobranch TEG results were observed using citrated fresh whole blood and the RapidTEG clot initiation reagent.

Thalamic activity-dependent specification of sensory input neurons in the developing chick entopallium.

During development, cell-intrinsic and cell-extrinsic factors play important roles in neuronal differentiation; however, the underlying mechanisms in nonmammalian species remain largely unknown. We here investigated the mechanisms responsible for the differentiation of sensory input neurons in the chick entopallium, which receives its primary visual input via the tectofugal pathway from the nucleus rotundus. The results obtained revealed that input neurons in the entopallium expressed Potassium Voltage-Gated Channel Subfamily H Member 5 (KCNH5/EAG2) mRNA from embryonic day (E) 11. On the other hand, the onset of protein expression was E20, which was 1 day before hatching. We confirm that entopallium input neurons in chicks were generated during early neurogenesis in the lateral and ventral ventricular zones. Notably, neurons derived from the lateral (LP) and ventral pallium (VP) exhibited a spatially distinct distribution along the rostro-caudal axis. We further demonstrated that the expression of EAG2 was directly regulated by input activity from thalamic axons. Collectively, the present results reveal that thalamic input activity is essential for specifying input neurons among LP- and VP-derived early-generated neurons in the developing chick entopallium.

Galf-Specific Neolectins: Towards Promising Diagnostic Tools.

In the absence of naturally available galactofuranose-specific lectin, we report herein the bioengineering of GalfNeoLect, from the first cloned wild-type galactofuranosidase (Streptomyces sp. strain JHA19), which recognises and binds a single monosaccharide that is only related to nonmammalian species, usually pathogenic microorganisms. We kinetically characterised the GalfNeoLect to confirm attenuation of hydrolytic activity and used competitive inhibition assay, with close structural analogues of Galf, to show that it conserved interaction with its original substrate. We synthetised the bovine serum albumin-based neoglycoprotein (GalfNGP), carrying the multivalent Galf units, as a suitable ligand and high-avidity system for the recognition of GalfNeoLect which we successfully tested directly with the galactomannan spores of Aspergillus brasiliensis (ATCC 16404). Altogether, our results indicate that GalfNeoLect has the necessary versatility and plasticity to be used in both research and diagnostic lectin-based applications.

Composition of encephalic arteries and origin of the basilar artery are different between vertebrates.

Intracranial arterial anatomy is lacking for most mammalian and non-mammalian model species, especially concerning the origin of the basilar artery (BA). Enhancing the knowledge of this anatomy can improve animal models and help understanding anatomical variations in humans. We have studied encephalic arteries in three different species of birds and eight different species of mammals using formalin-fixed brains injected with arterial red latex. Our results and literature analysis indicate that, for all vertebrates, the internal carotid artery (ICA) supplies the brain and divides into two branches: a cranial and a caudal branch. The difference between vertebrates lies in the caudal branch of the ICA. For non-mammalian, the caudal branch is the origin of the BA, and the vertebral artery (VA) is not involved in brain supply. For mammals, the VA supplies encephalic arteries in two different ways. In the first type of organization, mostly found in ungulates, the carotid rete mirabile supplies the encephalic arteries, the caudal branch is the origin of the BA, and the VA is indirectly involved in carotid rete mirabile blood supply. The second type of encephalic artery organization for mammals is the same as in humans. The caudal branch of the ICA serves as the posterior communicating artery, and the BA originates from both VAs. We believe that knowledge of comparative anatomy of encephalic arteries contributes to a better understanding of animal models applicable to surgical or radiological techniques. It improves the understanding of rare encephalic variations that may be present in humans.