Vertebrate Classes Research Articles

Influence of landscape and seasonality on roadkill of wild vertebrates in the surroundings of a protected area of the high-altitude Atlantic Forest

Roadkill is one of the main threats associated with highways, directly contributing to the depletion of natural populations. Here we establish the effect of landscape, seasonality and climatic variables on roadkill of wild vertebrates on two highways associated with Pedra Azul State Park (PEPAZ), state of Espírito Santo, southeastern Brazil. The highways BR-262 and ES-164 (20 km stretch in each road) were sampled monthly, between January and December 2015, totaling 60 days sampled/stretch. A total of 355 roadkilled vertebrates (Amphibia = 10; Reptilia = 40; Aves = 155; Mammalia = 149; undetermined = 1) distributed among at least 82 taxa were recorded (Amphibia = 4; Reptilia = 11; Aves = 47; Mammalia = 20). The roadkill rate was equivalent between highways, but birds were the most affected group on the ES-164 and mammals on the BR-262. A greater number of records were obtained during the rainy season for both highways. Temperature had a positive influence on the monthly roadkill rate, but no influence was observed from precipitation. The distance from water bodies and the type of land use and occupation influenced the roadkill records distribution. Roadkill of mammals was associated with areas of overgrown vegetation; birds with agricultural crops and built-up areas; and reptiles marginally with pasture areas. The effect of the highways was complementary because they affected the vertebrate classes differently. This could have severe impacts on biodiversity, highlighting that PEPAZ is part of an important ecological corridor of the Atlantic Forest in Espírito Santo. Speed control and installation of warning signs and wildlife crossing mechanisms are recommended to promote the long-term conservation of the regional biota.

Determinants of vertebrate species identification skills: A cross‐age study

AbstractVertebrate species knowledge is one of the predictors of pupils’ understanding of biodiversity. This study will describe vertebrate species identification skills of pupils from the Czech Republic. Altogether, the research tool included 30 vertebrate species, out of which five were fish, three were amphibians, three were reptiles, nine were birds, and 10 were mammals. The research tool consisted of 22 pictures, three footprints, two silhouettes, and three sounds. In addition, we evaluated the influence of variable factors on vertebrate species knowledge, which the research tool also contained. The paper will describe the percentage success rate of vertebrate species knowledge of 1537 respondents. On average pupils could identify nearly 15 species. The results showed that differences in species knowledge were statistically significant mostly by pupils’ expectations (self‐efficacy) or their results and educational level. In general, younger students identified animals worse than students of higher levels of education. Moreover, significant differences were confirmed between the five classes of vertebrates. Mammals were the best‐identified class, followed by amphibians and fish; reptiles and birds were the least correctly identified. While educational level played a significant role in identification skills, the results revealed that the pupils’ hometown did not play a significant role.

Cross‐scale scaling‐law analyses for the heterogeneity and diversity of animal gut microbiomes from community to landscape

Diversity and heterogeneity often are conflated but are fundamentally different. An aphorism proposed by Shavit and Ellison (2021; J. Phil. 118: 525–548) for distinguishing them is that ‘a zoo is diverse whereas an ecosystem is heterogeneous.' That is, a zookeeper measuring diversity simply enumerates the different types of animals; interactions are not expected to occur between animals separated by fences or other barriers. In contrast, measures of heterogeneity ought to include both interspecific interactions and relationships between species and their heterogeneous habitats. Here, we use cross‐scale, dual scaling‐law analyses of heterogeneity and diversity of animal gut microbiomes (AGMs) to address three objectives: 1) estimate the spatial heterogeneity and diversity of animal‐gut microbiomes; 2) analyze influences of phylogeny and diets on scaling of diversity and heterogeneity; 3) explore mechanistic differences between diversity and heterogeneity in AGMs. From 4903 AGM samples collected from 318 animal species covering all six classes of vertebrates and four major classes of invertebrates, we estimated that ≈640 000 operational taxonomic units (OTUs or ‘species') make up the pool of microbial species that could inhabit animal guts, among which ≈8000 are relatively common and ≈800 are dominant. The gut of any single animal, however, includes only 0.01–0.5% of the total species pool. We applied Ma's diversity‐area relationship for scaling diversity, and extend Taylor's power law and Luna et al.'s (2020; Diversity 12: 86) interaction diversity for scaling heterogeneity. At the community scale, phylogeny significantly influenced heterogeneity, but diets did not. Phylogeny and diets had limited influence on diversity at both community and landscape scales. We demonstrated that diversity and heterogeneity measure two different properties. Further, differences in scaling of diversity and heterogeneity are a result of heterogeneity being primarily the result of evolved dispersal behavior and interspecific interactions, whereas diversity results from abundances controlled on ecological time scales.

Homeotic and nonhomeotic patterns in the tetrapod vertebral formula

Vertebrate development and phylogeny are intimately connected through the vertebral formula, the numerical distribution of vertebrae along the body axis into different categories such as neck and chest. A key window into this relationship is through the conserved Hox gene clusters. Hox gene expression boundaries align with vertebral boundaries, and their manipulation in model organisms often results in the transformation of one vertebral type into its neighbor, a homeotic transformation. If the variety in the vertebrate body plan is produced by homeotic shifts, then the number of adjacent vertebrae will be inversely related when making interspecies comparisons since the gain in one vertebra is due to the loss in its neighbor. To date, such a pattern across species consistent with homeotic transitions has only been found in the thoracolumbar vertebral count of mammals. To further investigate potential homeotic relationships in other vertebrate classes and along the entire body axis, we compiled a comprehensive dataset of complete tetrapod vertebral formulas and systematically searched for patterns by analyzing combinations of vertebrae. We uncovered mammalian homeotic patterns and found balances between distal vertebrae not anticipated by a Hox-vertebral homeotic relationship, including one that emerged during the progression from theropods to birds. We also identified correlations between vertebral counts and intergenic distances in the HoxB gene cluster which do not align with the common picture of a colinear relationship between Hox expression and vertebral categories. This quantitative approach revises our expectations for the diversity of a Hox-mediated vertebrate body plan.

The Janus (dual) model of immunoglobulin isotype evolution: Conservation and plasticity are the defining paradigms.

The study of antibodies in jawed vertebrates (gnathostomes) provides every immunologist with a bird's eye view of how human immunoglobulins (Igs) came into existence and subsequently evolved into their present forms. It is a fascinating Darwinian history of conservation on the one hand and flexibility on the other, exemplified by the Ig heavy chain (H) isotypes IgM and IgD/W, respectively. The cartilaginous fish (e.g., sharks) Igs provide a glimpse of "how everything got off the ground," while the amphibians (e.g., the model Xenopus) reveal how the adaptive immune system made an about face with the emergence of Ig isotype switching and IgG-like structure/function. The evolution of mucosal Igs is a captivating account of malleability, convergence, and conservation, and a call to arms for future study! In between there are spellbinding chronicles of antibody evolution in each class of vertebrates and rather incredible stories of how antibodies can adapt to occupy niches, for example, single-domain variable regions, cold-adapted Igs, convergent mechanisms to dampen antibody function, provision of mucosal defense, and many more. The purpose here is not to provide an encyclopedic examination of antibody evolution, but rather to hit the high points and entice readers to appreciate how things "came to be."

Characterization of Immune Aging in the Japanese Medaka (Oryzias latipes)

The prevalence of chronic inflammation increases with age and may be aggravated by environmental exposures. Similarly, during immune aging, inflammatory disease incidence increases as protective immunity decreases. To better understand disease and exposure risks, an immune aging model outlining key changes in immune function is crucial. Utilizing the lowest possible vertebrate class, we propose the Japanese medaka (Oryzias latipes) as a model to investigate sex-specific immune aging including changes in immune gene expression, leukocyte profiles, and organismal level immune response. Evaluating the expression of immune initiators (CRP, TLR5-s, TLR5-m, TCRb, and MHCII), immune mediators (MYD88, Nf-kß, C3, and IL1b), and immune effectors (LYZ and C8) in concomitance with alterations in leukocyte populations and host resistance to pathogens will inform about immune competence across ages. The data presented here demonstrate a critical decrease in the expression of immune initiators (CRP, TLR5-soluble, TCRb, and MHCII), mediators (MYD88, Nf-kß, C3, and IL1b), and effector (LYZ) in both females and males after 11 months post hatching (mph). Interestingly, both sexes displayed an upregulation for the immune effector, C8, during this older life stage (11–13 mph). Gene expression profiles for both sexes at the most elderly age (20 or 23 mph) appear to revert to a younger profile of expression indicating a second change in immune function during aging rather than a steady decline. Significant changes in leukocyte populations were observed in both male and female medaka after peaking sexual maturation at 3 mph. Organismal level immune competence data revealed male medaka at the elderly age to be more vulnerable than their female and younger male counterparts while no differences were observed in females based on age. Together, these data provide a holistic profile for immune aging in medaka, a useful tool for future immunological studies considering age as a factor influencing disease susceptibility.

Retraction: Comparative study of the ciliary body and iris morphology in the anterior eye chamber of five different vertebrate classes.

A.A. Seleem, and A.H. Badr, 'Comparative Study of The Ciliary Body and Iris Morphology In The Anterior Eye Chamber of Five Different Vertebrate Classes', Anatomia Histologia Embryologia 53, no. 3 (2024): e13052, https://doi.org/10.1111/ahe.13052. The above article, published online on 12 May 2024 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the journal Editor-in-Chief, Fred Sinowatz; and Wiley-VCH GmbH, Published by John Wiley & Sons Ltd. The retraction has been agreed after an investigation found that this article was the resubmitted version of a manuscript which had been rejected a month previously, primarily due to concerns about compliance with animal ethical best practices concerning killing. Upon submission of the second manuscript, there was no clearly identifiable indication that it was a resubmission, as required by the journal during the submission process. Without knowledge that the new manuscript was the resubmission of a rejected manuscript, the new handling editors could not benefit from the peer review history. Because of this, they did not appreciate the necessity to confirm whether the ethical concerns raised in the rejected version had been addressed in the resubmitted version. Had the handling editors seen the peer review history, they would have rejected the second manuscript prior to peer review. Additionally, the second manuscript had been edited to omit mention of the unethical practice and investigators were therefore unable to verify which methods were used in the published study, nor could they evaluate them against the accepted ethical practices for handling animals. The authors responded to our inquiry but could not provide either adequate raw data or explanations for our concerns. Therefore, the article must be retracted. The authors have been informed of the retraction and Dr. Seleem, on behalf of both authors, disagrees with this decision.

Disentangling drivers of vertebrate roadkill in a protected area in the Amazon rainforest

AbstractVertebrates' roadkill impacts many species in natural areas. However, data on this topic in the Amazon domain are still scarce, especially within protected areas. In this study, we analysed data from 2 years of monitoring amphibians, reptiles, mammals and birds' roadkill on five types of terrestrial transport infrastructure in a protected area in the Brazilian Amazon. We tested which vertebrate classes and feeding guilds were most recorded, the influence of seasonality and the spatial pattern of roadkill. In the studied area, 2795 roadkills were recorded, with amphibians suffering the most casualties. Most of the roadkills occurred during the rainy season (57%). Correcting the roadkill data using observer efficiency and carcass persistence time data, we concluded that mortality rates might be underestimated by up to 40 times when compared to raw data. There was no significant difference between feeding guilds concerning the number of fatalities, and rainfall and temperature significantly affected the roadkill pattern of all vertebrate classes. The spatial pattern of roadkill varied between traffic routes and vertebrate class types. The results indicate that amphibians are the most common victims of roadkill, although they are neglected in many roadkill monitoring. Consequently, mitigation strategies should prioritize periods with the highest mortality rates, as rainfall and temperature influence the frequency of these accidents. In addition, different classes of vertebrates have different patterns of impact concentration along traffic routes, which makes mitigation planning more complex. Therefore, planning to reduce vertebrate deaths from roadkill must consider each taxon's particularity and seasonality.

Host Jump of an Exotic Fish Rhabdovirus into a New Class of Animals Poses a Disease Threat to Amphibians.

Spring viremia of carp virus (SVCV) is a rhabdovirus that primarily infects cyprinid finfishes and causes a disease notifiable to the World Organization for Animal Health. Amphibians, which are sympatric with cyprinids in freshwater ecosystems, are considered non-permissive hosts of rhabdoviruses. The potential host range expansion of SVCV in an atypical host species was evaluated by testing the susceptibility of amphibians native to the Pacific Northwest. Larval long-toed salamanders Ambystoma macrodactylum and Pacific tree frog Pseudacris regilla tadpoles were exposed to SVCV strains from genotypes Ia, Ib, Ic, or Id by either intraperitoneal injection, immersion, or cohabitation with virus-infected koi Cyprinus rubrofuscus. Cumulative mortality was 100% for salamanders injected with SVCV, 98-100% for tadpoles exposed to virus via immersion, and 0-100% for tadpoles cohabited with SVCV-infected koi. Many of the animals that died exhibited clinical signs of disease and SVCV RNA was found by in situ hybridization in tissue sections of immersion-exposed tadpoles, particularly in the cells of the gastrointestinal tract and liver. SVCV was also detected by plaque assay and RT-qPCR testing in both amphibian species regardless of the virus exposure method, and viable virus was detected up to 28 days after initial exposure. Recovery of infectious virus from naïve tadpoles cohabited with SVCV-infected koi further demonstrated that SVCV transmission can occur between classes of ectothermic vertebrates. Collectively, these results indicated that SVCV, a fish rhabdovirus, can be transmitted to and cause lethal disease in two amphibian species. Therefore, members of all five of the major vertebrate groups (mammals, birds, reptiles, fish, and amphibians) appear to be vulnerable to rhabdovirus infections. Future research studying potential spillover and spillback infections of aquatic rhabdoviruses between foreign and domestic amphibian and fish species will provide insights into the stressors driving novel interclass virus transmission events.

Crustacean endocrinology: Sexual differentiation and potential application for aquaculture

Crustaceans, which represent a significant subset of arthropods, are classified into three major classes: Ostracoda, Malacostraca, and Branchiopoda. Among them, sex manipulation in decapod species from the Malacostraca class has been extensively researched for aquaculture purposes and to study reproductive physiology and sexual plasticity. Some decapods exhibit sexual dimorphism that influences their biological and economic value. Monosex culture, in which only one sex is cultivated, increases production yields while reducing the risk of invasiveness, as genetic leakage into natural waters is less likely to occur. Differences in yield are also observed when cultivating different sexes, with all-male cultures of Macrobrachium rosenbergii being more profitable than both mixed and all-female cultures. Research on decapod sexual differentiation has led to a better understanding of sex determination and sexual differentiation processes in arthropods. Similar to most mammals and other vertebrate classes, Malacostraca crustaceans, including decapods, exhibit a cell-non-autonomous mode of sexual development. Genetic factors (e.g., sex chromosomes) and endocrine factors (e.g., insulin-like androgenic gland factor and crustacean female sex hormone) play pivotal roles in the development of sexually dimorphic traits. This review synthesizes the existing understanding of sex determination mechanisms and the role of sex hormones in decapod species. Additionally, it provides an overview of the methyl farnesoate, which has been suggested to be involved in male sex differentiation in some crab species, as well as the phenomenon of male-to-female sex reversal in host decapods caused by parasitic crustaceans.

Understanding the role of temperature in seasonal timing: Effects on behavioural, physiological and molecular phenotypes

AbstractOrganisms adapt to daily and seasonal environmental changes to maximise their metabolic and reproductive fitness. For seasonally breeding animals, photoperiod is considered the most robust cue to drive these changes. It, however, does not explain the interannual variations in different seasonal phenotypes. Several studies have repeatedly shown the influence of ambient temperature on the timing of different seasonal physiologies including the timing of migration, reproduction and its associated behaviours, etc. In the present review, we have discussed the effects of changes in ambient temperature on different seasonal events in endotherms with a focus on migratory birds as they have evolved to draw benefits from distinct but largely predictable seasonal patterns of natural resources. We have further discussed the physiological and molecular mechanisms by which temperature affects seasonal timings. The primary brain area involved in detecting temperature changes is the hypothalamic preoptic area. This area receives thermal inputs via sensory neurons in the peripheral ganglia that measure changes in thermoregulatory tissues such as the skin and spinal cord. For the input signals, several thermal sensory TRP (transient receptor potential ion channels) channels have been identified across different classes of vertebrates. These channels are activated at specific thermal ranges. Once perceived, this information should activate an effector function. However, the link between temperature sensation and the effector pathways is not properly understood yet. Here, we have summarised the available information that may help us understand how temperature information is translated into seasonal timing.

A SURVEY OF VERTEBRATES’ ROADKILL WITHIN A 10 KM RADIUS FROM THE CENTRE OF KUALA PILAH TOWN, NEGERI SEMBILAN

Assessing animal roadkill provides valuable insights into the diversity and abundance of different species within a particular area. This study has the potential to uncover factors influencing the occurrence of animal roadkill. However, there is a scarcity of studies focusing on animal roadkill in small, secluded areas such as the Kuala Pilah district, Negeri Sembilan. Thus, this study evaluates the composition and distribution of vertebrate roadkill within a 10 km radius from the centre of Kuala Pilah Town, with a focus on temporal (time of discovery), spatial (types of roads and types of surrounding areas), and environmental factors (the presence of streetlights). The road segments located within a 10 km radius from Kuala Pilah Town have been examined in ten weeks and the found carcasses were identified by their taxonomic groups and photographed. Further, their discovery location has been observed and marked with coordinates. A chi square test was then performed to evaluate the occurrence of animal roadkill with all recorded data. This study revealed 48 animal carcasses, with a taxonomic composition of 27.08% birds (13 individuals), 50% mammals (24 individuals), 18.75% reptiles (9 individuals), and 4.17% amphibians (2 individuals). The roadkill patterns showed that squirrels and cats as the most prevalent species found, with higher carcass rates found in plantation/forest areas and on state roads. Roadkill occurrences increased between 7 a.m. and 1 p.m., while streetlights had no noticeable impact on the numbers. Overall, mammals turned out to be the most frequent vertebrate class involved in roadkill with time being the only significant factor influencing the numbers. With a better understanding of the factors influencing vertebrate roadkill, mitigation strategies such as fencing, roadside vegetation clearance, and vehicle speed restrictions might be devised to minimize the adverse impacts of road infrastructure on local animal populations.

Recent advances in the therapeutic potential of cathelicidins.

The alarming increase in antimicrobial resistance in the last decades has prompted the search for alternatives to control infectious diseases. Antimicrobial peptides (AMPs) represent a heterogeneous class of molecules with ample antibacterial, antiviral, and antifungal effects. They can be found in many organisms, including all classes of vertebrates, providing a valuable source of new antimicrobial agents. The unique properties of AMPs make it harder for microbes develop resistance, while their immunomodulatory properties and target diversity reinforce their translational use in multiple diseases, from autoimmune disorders to different types of cancer. The latest years have witnessed a vast number of studies evaluating the use of AMPs in therapy, with many progressing to clinical trials. The present review explores the recent developments in the medicinal properties of cathelicidins, a vast family of AMPs with potent antimicrobial and immunomodulatory effects. Cathelicidins from several organisms have been tested in disease models of viral and bacterial infections, inflammatory diseases, and tumors, with encouraging results. Combining nanomaterials with active, natural antimicrobial peptides, including LL-37 and synthetic analogs like ceragenins, leads to the creation of innovative nanoagents with significant clinical promise. However, there are still important limitations, such as the toxicity of many cathelicidins to healthy host cells and low stability in vivo. The recent advances in nanomaterials and synthetic biology may help overcome the current limitations, enabling the use of cathelicidins in future therapeutics. Furthermore, a better understanding of the mechanisms of cathelicidin action in vivo and their synergy with other host molecules will contribute to the development of safer, highly effective therapies.

The effects of play stimulation on cognitive capacities of chickens

Play is a widespread phenomenon in the animal kingdom with observations from all vertebrate classes. The adaptive value of this behaviour, however, remains unclear. In the past century, numerous theories have been put forward, ranging from releasing surplus energy to training species-specific behaviours. However, none of these theories can fully explain the functions of play. A recent neurocognitive theory suggests that play allows the brain to encounter many different and surprising situations that provide it with opportunities to learn about the environment and form predictions about it. This theory has, however, to our knowledge, previously not been experimentally tested. To start exploring the connection between play and cognition, we compared the cognitive capacities of White Leghorn chicks that were stimulated to play in the first five weeks of their lives with chicks that did not receive any play stimulation. More specifically, we wanted to test the connection between specific types of play and cognitive domains. To achieve this, we designed two play treatments: object players that were provided with a variety of toys during their treatment, and social players that were released into an arena with plenty of space and conspecifics, as this has previously been shown to trigger social play. Subsequently, all three treatments (control, object players, social players) were tested in a cognitive test battery consisting of two experiments targeting the social domain and two targeting the physical domain. We found no improvement of cognitive capacities in either play treatment group compared to control subjects, though the social play treatment appears to have affected some behavioural variables recorded during the cognitive tests. Chicks that had played socially were in general bolder, more explorative and had more access to resources in the tests. This might subsequently allow them to exploit their environment more efficiently, which could in turn affect their welfare as they might be more resilient to stress and have more access to resources. More studies will be needed to assess the long-term effects of play on cognitive capacities and welfare of chickens.

The Chromatin Organization Close to SNP rs12913832, Involved in Eye Color Variation, Is Evolutionary Conserved in Vertebrates.

The most significant genetic influence on eye color pigmentation is attributed to the intronic SNP rs12913832 in the HERC2 gene, which interacts with the promoter region of the contiguous OCA2 gene. This interaction, through the formation of a chromatin loop, modulates the transcriptional activity of OCA2, directly affecting eye color pigmentation. Recent advancements in technology have elucidated the precise spatial organization of the genome within the cell nucleus, with chromatin architecture playing a pivotal role in regulating various genome functions. In this study, we investigated the organization of the chromatin close to the HERC2/OCA2 locus in human lymphocyte nuclei using fluorescence in situ hybridization (FISH) and high-throughput chromosome conformation capture (Hi-C) data. The 3 Mb of genomic DNA that belonged to the chromosomal region 15q12-q13.1 revealed the presence of three contiguous chromatin loops, which exhibited a different level of compaction depending on the presence of the A or G allele in the SNP rs12913832. Moreover, the analysis of the genomic organization of the genes has demonstrated that this chromosomal region is evolutionarily highly conserved, as evidenced by the analysis of syntenic regions in species from other Vertebrate classes. Thus, the role of rs12913832 variant is relevant not only in determining the transcriptional activation of the OCA2 gene but also in the chromatin compaction of a larger region, underscoring the critical role of chromatin organization in the proper regulation of the involved genes. It is crucial to consider the broader implications of this finding, especially regarding the potential regulatory role of similar polymorphisms located within intronic regions, which do not influence the same gene by modulating the splicing process, but they regulate the expression of adjacent genes. Therefore, caution should be exercised when utilizing whole-exome sequencing for diagnostic purposes, as intron sequences may provide valuable gene regulation information on the region where they reside. Thus, future research efforts should also be directed towards gaining a deeper understanding of the precise mechanisms underlying the role and mode of action of intronic SNPs in chromatin loop organization and transcriptional regulation.

Impacts of Exposure to Ultraviolet Radiation and an Agricultural Pollutant on Morphology and Behavior of Tadpoles (Limnodynastes tasmaniensis).

Amphibians are the most threatened vertebrate class globally. Multiple factors have been implicated in their global decline, and it has been hypothesized that interactions between stressors may be a major cause. Increased ultraviolet (UV) radiation, as a result of ozone depletion, has been identified as one such stressor. Exposure to UV radiation has been shown to have detrimental effects on amphibians and can exacerbate the effects of other stressors, such as chemical pollutants. Chemical pollution has likewise been recognized as a major factor contributing to amphibian declines, particularly, endocrine-disrupting chemicals. In this regard, 17β-trenbolone is a potent anabolic steroid used in the agricultural industry to increase muscle mass in cattle and has been repeatedly detected in the environment where amphibians live and breed. At high concentrations, 17β-trenbolone has been shown to impact amphibian survival and gonadal development. In the present study, we investigated the effects of environmentally realistic UV radiation and 17β-trenbolone exposure, both in isolation and in combination, on the morphology and behavior of tadpoles (Limnodynastes tasmaniensis). We found that neither stressor in isolation affected tadpoles, nor did we find any interactive effects. The results from our 17β-trenbolone treatment are consistent with recent research suggesting that, at environmentally realistic concentrations, tadpoles may be less vulnerable to this pollutant compared to other vertebrate classes. The absence of UV radiation-induced effects found in the present study could be due to species-specific variation in susceptibility, as well as the dosage utilized. We suggest that future research should incorporate long-term studies with multiple stressors to accurately identify the threats to, and subsequent consequences for, amphibians under natural conditions. Environ Toxicol Chem 2024;43:1615-1626. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

In vitro assessment of thyroid peroxidase inhibition by chemical exposure: comparison of cell models and detection methods

Disruption of the thyroid hormone (TH) system is connected with diverse adverse health outcomes in wildlife and humans. It is crucial to develop and validate suitable in vitro assays capable of measuring the disruption of the thyroid hormone (TH) system. These assays are also essential to comply with the 3R principles, aiming to replace the ex vivo tests often utilised in the chemical assessment. We compared the two commonly used assays applicable for high throughput screening [Luminol and Amplex UltraRed (AUR)] for the assessment of inhibition of thyroid peroxidase (TPO, a crucial enzyme in TH synthesis) using several cell lines and 21 compounds from different use categories. As the investigated cell lines derived from human and rat thyroid showed low or undetectable TPO expression, we developed a series of novel cell lines overexpressing human TPO protein. The HEK-TPOA7 model was prioritised for further research based on the high and stable TPO gene and protein expression. Notably, the Luminol assay detected significant peroxidase activity and signal inhibition even in Nthy-ori 3-1 and HEK293T cell lines without TPO expression, revealing its lack of specificity. Conversely, the AUR assay was specific to TPO activity. Nevertheless, despite the different specificity, both assays identified similar peroxidation inhibitors. Over half of the tested chemicals with diverse structures and from different use groups caused TPO inhibition, including some widespread environmental contaminants suggesting a potential impact of environmental chemicals on TH synthesis. Furthermore, in silico SeqAPASS analysis confirmed the high similarity of human TPO across mammals and other vertebrate classes, suggesting the applicability of HEK-TPOA7 model findings to other vertebrates.

Morphofunctional characteristics оs penis of mammals

ABSTRACT The aim of this work was to analyze the issues of the morphofunctional organization of the baculum (os penis) of mammals. In many mammals, to give strength and density to the organ, bone tissue is present in the penis, which forms the bone of the penis (os penis or baculum). This structure is evolutionarily young; it is present only in representatives of the evolutionarily youngest class of vertebrates - the class of mammals. The baculum is present in the penis of both marsupials and representatives of the orders of placental mammals (many rodents, some chiropterans, pinnipeds, cetaceans, some predators, prosimians and some monkeys). Bone tissue is usually located in the anterior region of the penis between the cavernous and spongy bodies. The baculum is an unpaired bone of an elongated shape; it can have the shape of a rod or plate, straight or curved. In cross-section, in representatives of different species, the bone can be round, square, triangular, or flat. Most often, the baculum is a cylindrical rod, expanded at the base and apex; in the proximal and distal parts there are outgrowths of various shapes. The histogenesis of bone tissue during the formation of the os penis in embryogenesis occurs via indirect osteogenesis. At the site of the future os penis, a cartilaginous model is formed from the mesenchyme, in place of which bone tissue then develops. The basis of the baculum is formed by lamellar bone tissue, in which osteons are well expressed. In the superficial zones of the baculum, coarse fibrous (reticulofibrous) bone tissue, as well as fibrous cartilaginous tissue, was identified. The baculum has been found to increase the overall rigidity of the penis when flexing during copulation. It was revealed that larger baculums are present in mammals, which are characterized by a longer duration of copulation.

Comparative study of the ciliary body and iris morphology in the anterior eye chamber of five different vertebrate classes.

One crucial component of the optical system is the ciliary body (CB). This body secretes the aqueous humour, which is essential to maintain the internal eye pressure as well as the clearness of the lens and cornea. The histological study was designed to provide the morphological differences of CB and iris in the anterior eye chambers of the following vertebrate classes: fish (grass carp), amphibians (Arabian toad), reptiles (semiaquatic turtle, fan-footed gecko, ocellated skink, Egyptian spiny-tailed lizard, Arabian horned viper), birds (common pigeon, common quail, common kestrel), and mammals (BALB/c mouse, rabbit, golden hamster, desert hedgehog, lesser Egyptian jerboa, Egyptian fruit bat). The results showed distinct morphological appearances of the CB and iris in each species, ranging from fish to mammals. The present comparative study concluded that the morphological structure of the CB and iris is the adaptation of species to either their lifestyle or survival in specific habitats.

How They Eat: An Examination of Digestive Physiology of Sympatric Prickleback Fishes

How fishes thrive on different diets is not understood as well as for terrestrial animals. Thus, examining the flexibility of gut function in fishes with different diets provides insight into dietary specialization in the largest vertebrate class. In this study, we measured the amylolytic activities in the guts of closely related, sympatric species: Xiphister mucosus (herbivore), X. atropurpureus (omnivore), Phytichthys chirus (omnivore), and Anoplacharus purpurescens (carnivore). For all species, the amylase activity decreased moving distally along the intestine, but less so for the carnivorous A. purpurescens. Overall, our results—more elevated amylase activity in those fish eating more algae—agree with the Adaptive Modulation Hypothesis (AMH), which suggests that there should be a match between enzymatic activity and dietary substrate intake. Measurements of proteases and lipases are in progress, but we anticipate some support for AMH in other enzyme classes. Moreover, we are also measuring these same enzyme activities in these same species fed omnivorous or carnivorous diets in the laboratory. The flexibility of the intestines of the fish species to accommodate different food types provides insight into their roles in the ecosystems and how fixed the vertebrate digestive system can be. NSF IOS 1355224 Undergraduate Research Opportunity Program at University of California, Irvine. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.