Reduced Body Size Research Articles

Diet Affects the Temperature–Size Relationship in the Blowfly Aldrichina grahami

In warmer environments, most ectotherms exhibit a plastic reduction in body size (the temperature–size rule, TSR). However, in such environments, growth is usually accelerated and would be expected to result in maturation at a larger body size, leading to increases in fecundity, survival, and mating success, compared to maturation at a smaller size (the ‘life-history puzzle’). To explore these mechanisms, we reared Aldrichina grahami at 20 °C, 25 °C, and 30 °C, and added a nutritional challenge by using dilutions of pork liver paste to provide diets that ranged in quality from high (undiluted) to moderate (1/8), low (1/16), and poor (1/24). Larvae were randomly sampled for weighing from hatching. Growth curves were fitted to the relationships between growth rate and weight for the third instar larvae. Our results showed that body size was affected by an interaction between temperature and diet, and that following or not following the TSR can vary depending on underfeeding. Moreover, when the TSR was followed as temperature increased, there was a cross-over point that divided the two growth curves into early and later stages, which could be used to help understand the life-history puzzle in warmer temperatures, with the instantaneous growth rate being faster in the early stages of development and then slower in later stages. This study reminds us that animals have evolved to cope with multiple simultaneous environmental changes, and it has thus offered a better understanding of life-history puzzles.

Notes on Chisosa (Araneae, Pholcidae), with the description of a new species from Mexico.

The genus Chisosa Huber, 2000 previously included only three species of small to tiny North American and Caribbean spiders that are rare in collections and poorly studied. Originally placed in the subfamily Ninetinae, Chisosa is currently considered a representative of Arteminae, close to the North American genus Physocyclus Simon, 1893. This placement has been suggested by molecular data, and it affects the interpretation of morphological characters that were originally thought to support the monophyly of Chisosa: they are shared with Physocyclus and thus plesiomorphic for Chisosa. Here we describe a new species from Mexico, C. calapa sp. nov., and restudy in detail the morphology (incl. ultrastructure) of the type species C. diluta (Gertsch & Mulaik, 1940) and of C. caquetio Huber, 2019, based on newly collected material. We document further similarities with Physocyclus but find only weak morphological support for the monophyly of Chisosa (body size reduction and short legs). In addition, we document surprisingly large genetic distances among C. caquetio specimens from Curaao (>14% CO1 K2P distances), possibly indicating species limits. Finally, we propose that the Dominican amber genus Serratochorus Wunderlich, 1988, based on a single male specimen, is also phylogenetically close to Chisosa and should be included in future studies on these enigmatic spiders.

Intestinal Mg2+ accumulation induced by cnnm mutations decreases the body size by suppressing TORC2 signaling in Caenorhabditis elegans

Mg2+ is a vital ion involved in diverse cellular functions by forming complexes with ATP. Intracellular Mg2+ levels are tightly regulated by the coordinated actions of multiple Mg2+ transporters, such as the Mg2+ efflux transporter, cyclin M (CNNM). Caenorhabditis elegans (C. elegans) worms with mutations in both cnnm-1 and cnnm-3 exhibit excessive Mg2+ accumulation in intestinal cells, leading to various phenotypic abnormalities. In this study, we investigated the mechanism underlying the reduction in body size in cnnm-1; cnnm-3 mutant worms. RNA interference (RNAi) of gtl-1, which encodes a Mg2+-intake channel in intestinal cells, restored the worm body size, confirming that this phenotype is due to excessive Mg2+ accumulation. Moreover, RNAi experiments targeting body size-related genes and analyses of mutant worms revealed that the suppression of the target of rapamycin complex 2 (TORC2) signaling pathway was involved in body size reduction, resulting in downregulated DAF-7 expression in head ASI neurons. As the DAF-7 signaling pathway suppresses dauer formation under stress, cnnm-1; cnnm-3 mutant worms exhibited a greater tendency to form dauer upon induction. Collectively, our results revealed that excessive accumulation of Mg2+ repressed the TORC2 signaling pathway in C. elegans worms and suggest the novel role of the DAF-7 signaling pathway in the regulation of their body size.

Smaller body size under warming is not due to gill-oxygen limitation in a cold-water salmonid.

Declining body size in fishes and other aquatic ectotherms associated with anthropogenic climate warming has significant implications for future fisheries yields, stock assessments and aquatic ecosystem stability. One proposed mechanism seeking to explain such body-size reductions, known as the gill oxygen limitation (GOL) hypothesis, has recently been used to model future impacts of climate warming on fisheries but has not been robustly empirically tested. We used brook trout (Salvelinus fontinalis), a fast-growing, cold-water salmonid species of broad economic, conservation and ecological value, to examine the GOL hypothesis in a long-term experiment quantifying effects of temperature on growth, resting metabolic rate (RMR), maximum metabolic rate (MMR) and gill surface area (GSA). Despite significantly reduced growth and body size at an elevated temperature, allometric slopes of GSA were not significantly different than 1.0 and were above those for RMR and MMR at both temperature treatments (15°C and 20°C), contrary to GOL expectations. We also found that the effect of temperature on RMR was time-dependent, contradicting the prediction that heightened temperatures increase metabolic rates and reinforcing the importance of longer-term exposures (e.g. >6 months) to fully understand the influence of acclimation on temperature-metabolic rate relationships. Our results indicate that although oxygen limitation may be important in some aspects of temperature-body size relationships and constraints on metabolic supply may contribute to reduced growth in some cases, it is unlikely that GOL is a universal mechanism explaining temperature-body size relationships in aquatic ectotherms. We suggest future research focus on alternative mechanisms underlying temperature-body size relationships, and that projections of climate change impacts on fisheries yields using models based on GOL assumptions be interpreted with caution.

Influences of ink-bottle effect evolution on water retention hysteresis of unsaturated soils: An experimental investigation

The ink-bottle effect, resulting from the non-uniformity of pore structure, plays a significant role in the hydraulic behaviour of soils. In this paper, a series of laboratory tests including standard mercury intrusion porosimetry (MIP), intrusion-extrusion cyclic MIP (IEC-MIP), and scanning electron microscopy (SEM) were conducted on two soils (a Nanyang expansive clay and a Kaolin mixture) to examine the evolution pattern of ink-bottle effect in soils with different initial void ratios. To evaluate the impact of such evolution on the soil-water retention behaviour, the axis translation and vapour equilibrium techniques were utilised to measure the water retention curve of the tested soils (SWRC). A key part of the analysis involved a separation between pore bodies (or ink-bottle pores) and pore throats to facilitate a more thorough examination of the pore structure. The test results indicated that the reduction in soil volume during compression is mainly attributed to the reduction in pore body size, whereas the pore throat size remains relatively constant. Therefore, the ink-bottle effect would weaken with a decreasing initial void ratio, which will reduce the hysteresis potential of soils, manifesting as a contraction of the SWRC hysteresis loop. Additionally, under a fixed void ratio but with decreasing pore size, the ink-bottle effect will also weaken, which will reduce the distance between the drying and wetting curves with increasing matric suction. Finally, the mechanisms regarding how the evolution of ink-bottle effect during soil deformation influences water retention hysteresis were addressed.

Toxicity assessment of a tebuconazole-based fungicide on the embryo-larval development of the common south American toad Rhinella arenarum.

Agrochemicals cause diverse effects on aquatic communities, and amphibian species are particularly threatened due the high susceptibility to contamination. Present study evaluates the toxicity of a widely used fungicide tebuconazole (Trigal®) by the assessment of mortality and developmental alterations at acute, subchronic, and chronic exposure during the embryo-larval development of the South American toad Rhinella arenarum. Also, the sensitivity of the different embryonic stages was evaluated with 24-h pulse exposure treatments. The results demonstrated that larvae were more sensitive than embryos at acute exposure (LC50-24 and 96 h = 74.62, 31.92 mg/L and 24.27, 16.81 mg/L for embryos and larvae, respectively). Nevertheless, embryos toxicity increased significantly achieving a sensitivity very similar to larvae at chronic exposure (LC50-168 and 504 h = 13.31, 4.35 mg/L and 14.47, 6.83 mg/L for embryos and larvae, respectively). Embryos exhibited several sublethal effects from 5 mg/L at 96 h onwards, such as delayed development, reduce body size, edemas, tail/axial flexures, weakness, and absence of movements. The teratogenic index at 96 h was 10.13, indicating the severe teratogenic potential of the fungicide. 24-h pulse exposure treatments showed an increased sensitivity in intermediate stages as S.11, S.18, S20, and S.23 (NOEC-96 h = 100, 200, 75, and 20 mg/L, respectively), while stage S.25 was the most sensitive to the fungicide (NOEC-96 h = 5 mg/L). About metamorphic process, tebuconazole caused an acceleration of metamorphosis at the lowest concentration (0.001 mg/L), but also an increase in mortality and in addition, significant differences in the weight in all treatments. The results obtained throughout this work indicate that tebuconazole cause several adverse effects in Rhinella arenarum embryo-larval development.

Activation of immune defences against parasitoid wasps does not underlie the cost of infection.

Parasites reduce the fitness of their hosts, and different causes of this damage have fundamentally different consequences for the evolution of immune defences. Damage to the host may result from the parasite directly harming its host, often due to the production of virulence factors that manipulate host physiology. Alternatively, the host may be harmed by the activation of its own immune defences, as these can be energetically demanding or cause self-harm. A well-studied model of the cost of infection is Drosophila melanogaster and its common natural enemy, parasitoid wasps. Infected Drosophila larvae rely on humoral and cellular immune mechanisms to form a capsule around the parasitoid egg and kill it. Infection results in a developmental delay and reduced adult body size. To disentangle the effects of virulence factors and immune defences on these costs, we artificially activated anti-parasitoid immune defences in the absence of virulence factors. Despite immune activation triggering extensive differentiation and proliferation of immune cells together with hyperglycaemia, it did not result in a developmental delay or reduced body size. We conclude that the costs of infection do not result from these aspects of the immune response and may instead result from the parasite directly damaging the host.

Urbanisation reduced body size but potentially improved flight performance in bees and wasps

Urbanisation is a main driver of land-use change, leading to rising in temperatures and fragmentation and reduction of green areas. Bees and wasps, which are important insect groups due to the ecosystem services they provide, may respond to this disturbance via changes in morphological traits which are functionally relevant. To date, studies focusing on this aspect only investigated few social bee species, and often gave contrasting results even at intra-generic level. Here, we studied how body size, wing loading, wing aspect ratio and wing fluctuating asymmetry vary in a social ground-nesting bee (Halictus scabiosae), a solitary hole-nesting bee (Osmia cornuta) and a social paper wasp (Polistes dominula) along an urbanisation gradient within Milan (Italy). By assessing the effects of temperature, green areas fragmentation and vegetation productivity on the above-listed functional traits, we found the three species to variably respond to increasing urbanisation, albeit the driving environmental parameters differed among species. More specifically, smaller individuals were sampled in warmer (for bees) and in less productive (for wasps) areas along the urbanisation gradient. Furthermore, greater wing aspect ratio values were recorded at warmer locations for H. scabiosae, lower wing loading was recorded at more fragmented sites for O. cornuta, and greater wing loading was recorded at locations with greater productivity for P. dominula. H. scabiosae and P. dominula showed greater wing fluctuating asymmetry at more fragmented sites. Although distinct species seemed sensitive to different driving factors, our results point toward a consistent response: smaller body but potentially improved flight performance in more urbanised environments.

Disruption of Leishmania flagellum attachment zone architecture causes flagellum loss.

Leishmania are flagellated eukaryotic parasites that cause leishmaniasis and are closely related to the other kinetoplastid parasites such as Trypanosoma brucei. In all these parasites there is a cell membrane invagination at the base of the flagellum called the flagellar pocket, which is tightly associated with and sculpted by cytoskeletal structures including the flagellum attachment zone (FAZ). The FAZ is a complex interconnected structure linking the flagellum to the cell body and has critical roles in cell morphogenesis, function and pathogenicity. However, this structure varies dramatically in size and organisation between these different parasites, suggesting changes in protein localisation and function. Here, we screened the localisation and function of the Leishmania orthologues of T. brucei FAZ proteins identified in the genome-wide protein tagging project TrypTag. We identified 27 FAZ proteins and our deletion analysis showed that deletion of two FAZ proteins in the flagellum, FAZ27 and FAZ34 resulted in a reduction in cell body size, and flagellum loss in some cells. Furthermore, after null mutant generation, we observed distinct and reproducible changes to cell shape, demonstrating the ability of the parasite to adapt to morphological perturbations resulting from gene deletion. This process of adaptation has important implications for the study of Leishmania mutants.

Disentangling the drivers of decadal body size decline in an insect population.

While climate warming is widely predicted to reduce body size of ectotherms, evidence for this trend is mixed. Body size depends not only on temperature but also on other factors, such as food quality and intraspecific competition. Because temperature trends or other long-term environmental factors may affect population size and food sources, attributing trends in average body size to temperature requires the separation of potentially confounding effects. We evaluated trends in the body size of the midge Tanytarsus gracilentus and potential drivers (water temperature, population size, and food quality) between 1977 and 2015 at Lake Mývatn, Iceland. Although temperatures increased at Mývatn over this period, there was only a slight (non-significant) decrease in midge adult body size, contrary to theoretical expectations. Using a state-space model including multiple predictors, body size was negatively associated with both water temperature and midge population abundance, and it was positively associated with 13 C enrichment of midges (an indicator of favorable food conditions). The magnitude of these effects were similar, such that simultaneous changes in temperature, abundance, and carbon stable isotopic signature could counteract each other in the long-term body size trend. Our results illustrate how multiple factors, all of which could be influenced by global change, interact to affect average ectotherm body size.

Rib remodelling changes with body size in fossil hippopotamuses from Cyprus and Greece

Large species that are isolated for thousands of years on islands often evolve extreme degrees of dwarfism. Very little is known about physiological processes that accompany such extreme transitions in extinct dwarf species. We tested whether physiological cycles of bone maintenance (remodelling) in dwarf adult hippopotamuses correlate with insularity-driven body mass shifts that may occur due to variables such as ecological release from predation pressure and change in access to resources. We hypothesised that hippopotamuses with the smallest body size should show higher values of osteocyte lacunae, proxies for osteoblast proliferation during cycles of remodelling, when compared to relatively larger dwarf forms, as well as much larger mainland common hippopotamuses. We examined 20 ribs from three extinct Pleistocene Hippopotamus species spanning a gradient in body size: H. minor (~132 kg, Cyprus), H. creutzburgi (~398 kg, Crete), and H. antiquus (~3200 kg, mainland Greece). Ribs were selected because they reflect bone metabolic rates that are not completely clouded by factors such as biomechanics. Densities of osteocyte lacunae (Ot.Dn) were examined in 864 individual secondary osteons observed in histology sections. We found the highest average Ot.Dn in the H. minor ribs, intermediate Ot.Dn in the H. creutzburgi ribs, and the lowest Ot.Dn in the H. antiquus ribs. It appears that Ot.Dn distinctly separated these three species, possibly signifying a gradient in bone remodelling such that bone tissue optimises maintenance in the face of insularity-driven reduction of body size. We discuss hippopotamus rib bone microstructure and the utility of Ot.Dn in palaeontological analyses for elucidating intricate biological processes occurring in bone of insular fossil mammals.

Two zebrafish cacna1s loss-of-function variants provide models of mild and severe CACNA1S-related myopathy.

CACNA1S-related myopathy, due to pathogenic variants in the CACNA1S gene, is a recently described congenital muscle disease. Disease associated variants result in loss of gene expression and/or reduction of Cav1.1 protein stability. There is an incomplete understanding of the underlying disease pathomechanisms and no effective therapies are currently available. A barrier to the study of this myopathy is the lack of a suitable animal model that phenocopies key aspects of the disease. To address this barrier, we generated knockouts of the two zebrafish CACNA1S paralogs, cacna1sa and cacna1sb. Double knockout fish exhibit severe weakness and early death, and are characterized by the absence of Cav1.1 α1 subunit expression, abnormal triad structure, and impaired excitation-contraction coupling, thus mirroring the severe form of human CACNA1S-related myopathy. A double mutant (cacna1sa homozygous, cacna1sb heterozygote) exhibits normal development, but displays reduced body size, abnormal facial structure, and cores on muscle pathologic examination, thus phenocopying the mild form of human CACNA1S-related myopathy. In summary, we generated and characterized the first cacna1s zebrafish loss-of-function mutants, and show them to be faithful models of severe and mild forms of human CACNA1S-related myopathy suitable for future mechanistic studies and therapy development.

A toxin-antidote selfish element increases fitness of its host.

Selfish genetic elements can promote their transmission at the expense of individual survival, creating conflict between the element and the rest of the genome. Recently, a large number of toxin-antidote (TA) post-segregation distorters have been identified in non-obligate outcrossing nematodes. Their origin and the evolutionary forces that keep them at intermediate population frequencies are poorly understood. Here, we study a TA element in Caenorhabditis elegans called zeel-1;peel-1. Two major haplotypes of this locus, with and without the selfish element, segregate in C. elegans. We evaluate the fitness consequences of the zeel-1;peel-1 element outside of its role in gene drive in non-outcrossing animals and demonstrate that loss of the toxin peel-1 decreased fitness of hermaphrodites and resulted in reductions in fecundity and body size. These findings suggest a biological role for peel-1 beyond toxin lethality. This work demonstrates that a TA element can provide a fitness benefit to its hosts either during their initial evolution or by being co-opted by the animals following their selfish spread. These findings guide our understanding on how TA elements can remain in a population where gene drive is minimized, helping resolve the mystery of prevalent TA elements in selfing animals.

The effectiveness of ichthyochoric dispersal in forested wetlands of the Amazon depends on the species of fish and its size

The interaction between fish and plants in Amazon floodplain is fundamental for the maintenance of frugivorous fish and tree communities. The viability of seeds after passing through the digestive tract of fish is a central factor for seed dispersal since it can influence colonization and regeneration of these environments. Our study investigated the seed dispersal by frugivorous fish in a flooded forest in the Central Amazon. We also evaluated the seed germination speed after passage of the digestive tract of fish and how the size of fish and the seeds can influence the dispersion of tree seeds in floodplains. A total of 5,012 seeds from 49 plant species were found in the digestive tracts of 11 frugivorous fish species. The length and weight of the frugivorous fish were positively related to the size of seeds in the digestive tract. The germination of the seeds removed from the fish varied between species. The passage of the seeds of the different plant species through the digestive tracts of the fish did not significantly increase the germination speed. Considering the anthropogenic pressures present in these environments, we can expect that a reduction in body size for some species of fish, due to overexploitation, may have negative consequences for some tree species that are dispersed mainly via ichthyochory.

Land-use-associated stressors interact to reduce bumblebee health at the individual and colony level.

In agricultural landscapes, bees face a variety of stressors, including insecticides and poor-quality food. Although both stressors individually have been shown to affect bumblebee health negatively, few studies have focused on stressor interactions, a scenario expected in intensively used agricultural landscapes. Using the bumblebee Bombus terrestris, a key pollinator in agricultural landscapes, we conducted a fully factorial laboratory experiment starting at nest initiation. We assessed the effects of food quality and insecticides, alone and in interaction, on health traits at various levels, some of which have been rarely studied. Pollen with a diluted nutrient content (low quality) reduced ovary size and delayed colony development. Wing asymmetry, indicating developmental stress, was increased during insecticide exposure and interactions with poor food, whereas both stressors reduced body size. Both stressors and their interaction changed the workers' chemical profile and reduced worker interactions and the immune response. Our findings suggest that insecticides combined with nutritional stress reduce bumblebee health at the individual and colony levels, thus possibly affecting colony performance, such as development and reproduction, and the stability of plant-pollinator networks. The synergistic effects highlight the need of combining stressors in risk assessments and when studying the complex effects of anthropogenic stressors on health outcomes.

Fish body size influenced by multiple drivers

There is evidence that organisms have become smaller during the past periods of global warming. Global change has substantial effects on biodiversity, with body size reduction being the third most common response to global warming. Body size allometry in ectotherms needs to be explored further; the objectives of this study were to better understand the mechanisms regulating body size in fish by testing: 1) Bergmann's rule with temperature and elevation, 2) additional environmental drivers, 3) the role of isolation, 4) ecoevolutionary hypotheses comparing native and exotic species and 5) the role of migration propensity in comparing migratory and resident species. We analyzed an extensive dataset of Chilean fish composed of 75 198 records which included 25 species from 12 different families between latitudes −28.80 to −51.42 using linear mixed models to discern the best environmental variables contributing to body size changes, as well as incorporating factors related to dispersal capabilities, biogeographic isolation and levels of exotic/native interactions. Bergmann's rule is supported by changes in elevation, and our study shows that freshwater fish body size also increases with increasing environmental heterogeneity and productivity. In general, inland native fish tend to be smaller than coastal ones, supporting the island rule with evidence of gigantism or dwarfism in selected species. Ecological variables affecting fish body size do not differ between native and exotic fish unless other factors are considered, such as dispersal capacity (migrating vs resident fish) or mechanisms related to their isolation. Although temperature is not a direct driver of body size in Chilean fish, heterogeneity, productivity, geography, migratory ability and species origin may affect body size. A better understanding of the mechanisms driving body size in ectotherms will aid in determining management priorities in the face of global climate disruption.

Identification of side effects of COVID-19 drug candidates on embryogenesis using an integrated zebrafish screening platform

Drug repurposing is an important strategy in COVID-19 treatment, but many clinically approved compounds have not been extensively studied in the context of embryogenesis, thus limiting their administration during pregnancy. Here we used the zebrafish embryo model organism to test the effects of 162 marketed drugs on cardiovascular development. Among the compounds used in the clinic for COVD-19 treatment, we found that Remdesivir led to reduced body size and heart functionality at clinically relevant doses. Ritonavir and Baricitinib showed reduced heart functionality and Molnupiravir and Baricitinib showed effects on embryo activity. Sabizabulin was highly toxic at concentrations only 5 times higher than Cmax and led to a mean mortality of 20% at Cmax. Furthermore, we tested if zebrafish could be used as a model to study inflammatory response in response to spike protein treatment and found that Remdesivir, Ritonavir, Molnupiravir, Baricitinib as well as Sabizabulin counteracted the inflammatory response related gene expression upon SARS-CoV-2 spike protein treatment. Our results show that the zebrafish allows to study immune-modulating properties of COVID-19 compounds and highlights the need to rule out secondary defects of compound treatment on embryogenesis. All results are available on a user friendly web-interface https://share.streamlit.io/alernst/covasc_dataapp/main/CoVasc_DataApp.py that provides a comprehensive overview of all observed phenotypic effects and allows personalized search on specific compounds or group of compounds. Furthermore, the presented platform can be expanded for rapid detection of developmental side effects of new compounds for treatment of COVID-19 and further viral infectious diseases.

The molecular underpinnings of body size regulation: Transcriptional changes in foxo and mTor in Drosophila melanogaster selected for fast development

One of biology's most perplexing ideas is the biological control of an organism's size. Even if many questions remain unanswered, it can be logically implied that the size of an individual is clearly correlated with its cell number and cell size. Size regulation, which happens through the control of cell size and number, is crucial for the development of multicellular organisms. Long term selection of Drosophila melanogaster for fast development has led to reduction in body size. In this study, we compared three types of D. melanogaster populations- the first were selected for fast development and short effective lifespan (FEJs), second were selected for fast development and longer effective lifespan (FLJs) and the third were their ancestral control populations (JBs), and answered whether up-regulation of foxo (forkhead box, subgroup-o) and/or down regulation of mTor (mechanistic Target of rapamycin) is responsible for reduction in organismal size in fast developing D. melanogaster. Our results show that upregulation of foxo might be responsible for reduction in size in both FLJs and FEJs. Further, higher mTor in FEJs but no change in mTor in FLJs in comparison to JBs confirms that selection for fast development does not lead to starvation like phenotype or stress like conditions in D. melanogaster. Furthermore, this difference in mTor in FEJs and FLJs might be due to selection for short effective lifespan and long effective lifespan respectively, as suppression or blocking mTor expression has been reported to extend lifespan. These results suggest that potentially deleterious allele for late life is under positive selection in FEJs but not in FLJs.

MORPHOLOGICAL INDICATORS OF THE NARROW-CRUSTED VOLE OF THE ANTHROPOGENIC TERRITORY OF NORTH-EASTERN KAZAKHSTAN

This study delves into the intricate relationships between ecological factors, adaptation, and the effects of anthropogenic activities on small mammals in the Northeastern region of Kazakhstan. External traits, including body mass, length, tail length, ear height, and hind foot length, provide valuable insights into adaptive adjustments in response to various climatic and ecological conditions. Industrial areas reveal a reduction in average body mass, attributed to patchy vegetation and proximity to factories and roads. Size variations are closely tied to food availability, with a reduction in body size and growth rates observed in technogenic zones. Tail sizes differ by age and sex, while foot sizes tend to even out as animals mature. Notably, anthropogenic pollution has minimal impact on ear length. The heart index reflects an individual’s mobility and thermoregulation, while the liver index is influenced by food availability and energy resources. Notably, the analysis extends beyond average differences, considering the range of variability to identify increased diversity, even in ecologically challenging areas. Small mammals exhibit a high metabolic rate and limited physiological stress adaptability, yet the population demonstrates remarkable adaptation. Enlarged heart indices suggest increased locomotor activity associated with overcoming anthropogenic barriers, such as railways and highways. In addition to heart indices, liver mass calculations reflect the accumulation of energy reserves and materials for growth. The study highlights that the liver mass index of field mice in industrial zones exceeds that of the control group, indicating the impact of anthropogenic activities on these organisms. This research provides valuable insights into the intricate relationships between ecological factors, adaptation, and human influence on small mammal populations in the Northeastern region of Kazakhstan. Keywords: small mammals, narrow-crusted vole, morphophysiological indicators method, exterior signs, interior signs.

Effects of the major formaldehyde catalyzer ADH5 on phenotypes of fanconi anemia zebrafish model.

Fanconi anemia (FA) is a devastating hereditary disorder for which we desperately need a novel therapeutic strategy. It is caused by mutations in one of at least 22 genes in the FA pathway and is characterized by developmental abnormalities, bone marrow failure, and cancer predisposition. The FA pathway is required for the efficient repair of damaged DNA, including interstrand cross-links (ICL). Recent studies indicate formaldehyde as an ultimate endogenous cause of DNA damage in FA pathophysiology. Formaldehyde can form DNA adducts as well as ICLs by inducing covalent linkages between opposite strands of double-stranded DNA. In this study, we generated a disease model of FA in zebrafish by disrupting the ube2t or fancd2 gene, which resulted in a striking phenotype of female-to-male sex reversal. Since formaldehyde is detoxified from the body by alcohol dehydrogenase 5 (ADH5), we generated fancd2-/-/adh5-/- zebrafish. We observed a body size reduction and a lower number of mature spermatozoa than wild-type or single knockout zebrafish. To evaluate if increased activity in ADH5 can affect the FA phenotype, we overexpressed human ADH5 in fancd2-/- zebrafish. The progress of spermatogenesis seemed to be partially recovered due to ADH5 overexpression. Our results suggest potential utility of an ADH5 enzyme activator as a therapeutic measure for the clearance of formaldehyde and treatment of FA.