Periodicity thresholds and optimal control in a negative chemotaxis system with cell death

Trypanosomosis is a serious constraint to livestock productivity in Ethiopia, affecting a wide range of hosts. A cross-sectional study was conducted from October 2023 to December 2023 to determine the prevalence of trypanosomosis in small ruminants and its associated risk factors in the Abe Dongoro district, Oromia Regional State, western Ethiopia. A multi-stage sampling approach was employed for this study. A total of 390 blood samples (308 sheep and 82 goats) were collected from the ear vein using a random sampling method, considering various agro-ecological kebeles, body condition, age, and sex. The wet blood film examination and buffy coat technique were employed to determine the prevalence of trypanosomosis, and Giemsa-stained thin smears were used for species identification. Logistic regression analysis was used to assess associations between parasitic infection and risk factors. The overall prevalence of trypanosomosis in small ruminants was 17.69% (69/390), with 15.9% (49/308) in sheep and 24.39% (20/82) in goats. The dominant species of Trypanosoma identified were T. congolense (6.66%), T. vivax (4.87%), and T. brucei (1.02%), with mixed infections accounting for 5.13%. The difference in prevalence among parasite species was not statistically significant ( P > 0.05). The study indicated that infection prevalence varied significantly across kebeles, body condition scores, and sex categories ( P < 0.05). However, there was no statistically significant difference between age categories of animals ( P > 0.05). The mean Packed Cell Volume (PCV) analysis recorded values of 20.76 ± 2.675 in parasitemic sheep and goats, compared to 26.78 ± 2.551 in aparasitemic individuals, revealing a significant statistical difference between the two groups ( P < 0.05). The study concluded that trypanosomosis is prevalent in sheep and goats, with significant anemia and poor body condition in infected animals representing substantial productivity losses for smallholder farmers. The identification of kebele, sex, and body condition as independent risk factors enables targeted interventions. These findings underscore the urgent need for integrated control strategies combining vector control in high-risk areas, strategic trypanocidal drug use, and community education on animal husbandry practices to mitigate disease impact and improve livestock productivity in the region. • Trypanosomosis prevalence is 17.69% in small ruminants in Abe Dongoro, Ethiopia. • T. congolense is the dominant Trypanosoma species in infected animals. • Parasite infection significantly lowers packed cell volume (PCV). • Prevalence varies significantly with body condition and agroecology.

The Biological Species Criterion in Practice: Distinguishing Fern Species from their Sterile Hybrids Using Quantitative Spore Characters

Introduction. Chronic stress and paracetamol exposure are among the most relevant factors affecting neurochemical and molecular processes in the brain in modern humans. Excessive activation of inflammatory and oxidative pathways during chronic psychosocial stress can lead to a decrease in the expression of neuroprotective and antioxidant genes, exacerbating the neurotoxic effects of drugs such as paracetamol.Objective. To assess the effect of chronic unpredictable stress and oral administration of paracetamol, as well as their combined effect on the morphological state of the brain and on the expression of genes of the antioxidant system and neurotrophic factor in the hippocampus in rats.Materials and methods. The experiment was conducted on forty eight rats (males and females in equal numbers), divided into four groups: control, chronic stress, paracetamol, combined exposure to stress and paracetamol. A complex of various stressors was used to model chronic stress. Paracetamol was administered orally at a dose of 1000 mg/kg. The morphological state of the hippocampus was assessed histologically, gene expression - by quantitative real-time PCR. Statistical analysis included bootstrapping and correction for multiple comparisons using the Holm-Bonferroni method.Results. Macroscopic and histological examination of the rat brain showed the preservation of the normal anatomical structure and integrity of the hippocampal tissues in all groups. Statistical analysis of gene expression showed animals treated with paracetamol (groups III and IV) to show a significant decrease in the mRNA levels in the Sod1 and Bdnf genes in the hippocampus compared to the control and the group exposed to stress only (group II). The expression level of Sod1 and Bdnf was significantly lower in both males and females in these groups (p = 0.001). For the Hmox1 gene, a significant decrease in expression was found only in males in the paracetamol-treated group, while no changes were noted in females.Limitations. Laboratory animals of the same biological species were used for the experiment, and the toxicant was used in only one concentration.Conclusion. Thus, paracetamol, both in isolated use and in combination with chronic stress, has a more pronounced inhibitory effect on the expression of key genes of antioxidant protection and neurotrophic support than stress alone.Compliance with ethical standards. Date of the meeting of the bioethics commission of theUfa Research Institute of Occupational Medicine and Human Ecology dated 02/08/2024 No. 01–02. Throughout the study, the animals were kept in standard conditions with 12-hour artificial lighting during the daytime, a relatively constant level of humidity (30–70%) and an air temperature of 20–25 °C. All animal manipulations were carried out in strict compliance with the rules prescribed in the basic regulatory documents, including the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (Strasbourg, 1986) and the Helsinki Declaration on the Humane Treatment of Animals.Contributions: Gizatullina A.A. – concept and study design, material collection and processing, statistical analysis, manuscript writing; Valova Ya.V. – material collection and processing, statistical analysis; Mukhamadieva G.F. – editing; Karimov D.O. – concept and study design, statistical analysis; Karimov D.D. – material collection and processing; Ryabova Yu.V. – material collection and processing; Khusnutdinova N.Yu. – material collection and processing; Khmel A.O. – material collection and processing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. Industry research program of Rospotrebnadzor for 2021–2025 “Scientific substantiation of the national system for ensuring sanitary and epidemiological welfare, managing health risks and improving the quality of life of the population of Russia”, on the topic: 6.9.1.2 “Study of the impact of chemical production factors under conditions of chronic stress” No. NIOKTR I124021200153-3.Received: April 30, 2025 / Revised: July 9, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Three-dimensional genome organization controls cell-type-specific gene expression through chromatin interactions, yet systematic analysis across diverse cellular contexts remains limited by experimental constraints. Here we present Hi-Compass, a depth-aware deep learning framework that predicts cell-type-specific chromatin organization using only chromatin accessibility data as cell-type-specific input. By dynamically accommodating variability in sequencing depth, Hi-Compass enables robust predictions across the full spectrum of data scales, from sparse single-cell to high-coverage bulk profiles. Benchmarking shows that Hi-Compass achieves superior concordance with experimental Hi-C data compared to existing methods, with particularly strong recovery of high-confidence chromatin loops. Applied to peripheral blood and embryonic heart datasets, Hi-Compass resolves cell-type-specific chromatin interactions and systematically links disease-associated variants to putative target genes. The framework further enables spatially resolved chromatin interaction prediction in hippocampal tissue and demonstrates cross-species applicability through fine-tuning to mouse systems. Hi-Compass expands the capacity to study three-dimensional genome regulation across biological scales and species.

"What is an avatar?" The popular imagery of the 2009 film of the same name by James Cameron and its two sequels has significantly influenced the public's conception of the term "avatar." Although the term is derived from Sanskrit and refers to the incarnation of a divine being in human or animal form, popular culture instinctively associates it with the blue mythical creatures that inhabit the planet Pandora in Cameron's films and are called Na'vi. In the film's mythological narrative, the Na'vi—the indigenous inhabitants of the planet—are depicted as both natural beings and subjects of biotechnological experimentation. Their DNA can be engineered in a laboratory setting to be controlled by a human via a neural interface. As suggested by the name, the Na'vi are "natives" as an original biological species. However, as biotechnological clones, they assume the role of navigators ("Navi" in the abbreviation), who can also be controlled and moved by humans who, like the protagonist Jake Sully in Avatar, are paraplegic. In order to visually distinguish Sully as the film's hero from the mass of other Na'vi, his face is designed to be somewhat more anthropomorphic. However, there are no visual markers that would indicate an ontological difference between the original and the avatar.

Over the past decade, the tourism sector in the karst region of Gunung Kidul has experienced substantial growth, contributing significantly to local revenue generation and expanding employment opportunities for surrounding communities. Nevertheless, the rapid development of tourism infrastructure, land-use conversion, and intensive exploitation of karst landscapes have generated constitutional concerns related to the State’s obligation to safeguard environmental sustainability. Karst ecosystems perform essential ecological functions, including groundwater storage, hydrological regulation, and providing habitats for diverse biological species. Consequently, environmental degradation in these areas may result in long-term ecological consequences. This study aims to examine the tension between tourism-driven economic development and the protection of karst environments from the perspective of Article 33 of the 1945 Constitution of the Republic of Indonesia, as well as the principles of sustainable development. The research employs a socio-legal approach, combining normative analysis of statutory regulations with conceptual examination of the green constitution doctrine and sustainable development framework. The findings indicate that Article 33 of the 1945 Constitution not only emphasizes state control over natural resources for the prosperity of the people but also implicitly incorporates principles of environmental sustainability and ecological responsibility. Accordingly, tourism policies that disregard environmental carrying capacity and ecological limits within karst regions risk contradicting constitutional mandates. The integration of sustainable development principles into spatial planning policies and licensing mechanisms is therefore essential to ensure a balanced relationship between economic advancement and environmental preservation.

Butyrylcholinesterase (BChE) is closely associated with Alzheimer's disease (AD), with its expression significantly elevated in the brains of AD patients. This enzyme has emerged as a potential biomarker for monitoring AD progression. Therefore, developing a reliable chemical tool to detect BChE both in vitro and in vivo is of considerable interest. In this study, we rationally designed a series of environmentally sensitive fluorescent probes targeting BChE, based on a highly potent, selective, and reversible BChE inhibitor. Among these, the most promising probe ESP4 demonstrated an ultrafast response to BChE with exceptional sensitivity (LOD = 1.81 nM), enabling high-precision detection of BChE. Additionally, ESP4 maintained robust inhibitory activity against BChE in the low nanomolar range (IC50 = 71.78 ± 1.90 nM). Notably, ESP4 exhibited excellent selectivity for BChE, showing no interference from other biological species, including acetylcholinesterase (AChE). The probe also accurately measured the IC50 of tacrine (7.83 nM), a standard BChE inhibitor, demonstrating its reliability in evaluating BChE inhibition. Due to its high sensitivity, rapid response, and superior selectivity, ESP4 enabled real-time imaging of BChE in biological systems such as cells, zebrafish, and AD mouse models. Collectively, these findings highlighted ESP4 as a valuable tool for BChE detection, contributing to a deeper understanding of the physiological role of BChE in health and disease.

Studies on the effects of γ-radiation on nonhuman primate (NHP) brains are limited, despite the critical need to understand the impact of radiation exposure on the brain from various sources like radiotherapy equipment, space travel, and potential nuclear events. We investigated molecular and neuropathological changes in rhesus macaque brains after a single 5.8 Gy total-body γ-radiation exposure. We analyzed samples dissected from frontal cortex (FCtx), hippocampus (Hippo), and cerebellum (CRB) of irradiated (RAD) vs. unirradiated/control (CTRL) animals. Western blotting and digital PCR (dPCR) analyses were used to measure different phosphorylated-Tau (pTau) forms and neurodegeneration markers (i.e., amyloid protein precursor [APP], neurofilament-light chain [NFL], glial fibrillary acidic protein [GFAP], ionized calcium-binding adapter molecule 1 [IBA1/AIF1], and myelin basic protein [MBP]). We detected lower levels of different forms of soluble pTau species (pTau181, and pTau217, among others) in RAD vs. CTRL animals across all three examined brain regions. While APP and GFAP levels were unchanged in the FCtx, increased IBA1 and NFL levels were detected alongside decreased MBP levels. Moreover, dPCR data identified decreased expression of GFAP and MBP in the FCtx. Importantly, the molecular changes observed were not accompanied by overt signs of neurodegeneration or cellular abnormalities upon neuropathological assessment. These findings in irradiated NHPs' brains are novel and indicate that a single total-body γ-radiation exposure significantly alters soluble pTau levels after a few weeks from irradiation without causing obvious neurohistological damage. These results open intriguing new possibilities of exploring γ-radiation-based strategies to modulate the progression of tauopathies, including Alzheimer's disease.

In this study, a novel hybrid molecularly imprinted polymer (MIP)-based biomimetic sensor was fabricated, optimized, characterized, and applied for the electrochemical recognition of catalase (CAT), an antioxidant biomarker. A layer-by-layer approach was followed to prepare the hybrid sensor. First, silver nanoparticles (AgNPs) were deposited by chronoamperometry on a bare glassy carbon electrode (GCE) for 300s, followed by drop-casting of multi-walled carbon nanotubes (MWCNTs). The MIP was then produced by ten voltammetric electropolymerization cycles using ortho-aminophenol (OAP) as a functional monomer in the presence of catalase as a template on the MWCNT/AgNP/GCE surface at a potential range of -0.2V to 0.8V. The fabricated sensor exhibited a rapid response toward CAT within a linear range of 25-500U/mL and a limit of detection (LOD) of 3.59U/mL, with no cross-reactivity toward several tested possible biological species. CAT was also successfully detected in biological samples, with recovery percentages ranging from 95.73% to 101.60% and relative standard deviation (RSD) of 0.41-1.52%, which is comparable to the results for a commercial diagnostic reference kit, without the need for complicated sampling procedures. The sensor performance is dependent on catalase molecular recognition rather than reactivity towards its substrate. This feature, in addition to the sensor's low cost and portability, positions it as a promising candidate for use in point-of-care diagnostics in the medical field.

Biodiversity surveys require an appropriate sampling design for optimal performance and comparability across space and time and across studies. Based on PacBio and Illumina amplicon sequencing of animals, bacteria and fungi, we assessed and compared various soil sampling designs from widely used continental and global metabarcoding-based biodiversity projects. Sampling designs revealed up to 27-fold, 6-fold and 15-fold differences in biodiversity estimates for animals, bacteria and fungi, respectively. Taxonomic coverage depended mostly on the number of subsamples but not sampling area within the 347-1790 m2, 428-1924 m2, 327-1790 m2 plot size range for animals, bacteria and fungi, respectively. Additional sampling of subsoil did not add significantly to diversity estimates of animals and fungi, although there was a slight positive effect on bacteria. Both soil pooling (compositing subsamples before DNA extraction) and DNA pooling (combining DNA extracts prior to PCR) reduced differences between sampling designs by decreasing diversity estimates in designs with many subsamples while increasing them in designs with fewer subsamples. However, pooling did not eliminate the influence of sampling factors (soil depth, sampling area and sample size). DNA pooling outperformed soil pooling in inventorying animals and fungi but not bacteria. Pooling had no effect on recovering rare biological species or sequencing artefacts. Soil pooling saved from 79.5% to 98.3% of labour and analytical costs compared with no pooling, depending on the number of pooled subsamples. The remarkable impact of sampling design on community diversity and composition should be considered during data collection and meta-analyses compiling data from different sampling designs.

The article presents an interdisciplinary analysis of human settlements through the perspectives of ecology, biogeography, and ecosystem theory. Rural and urban settlements are interpreted not as socio-economic or infrastructural formations, but as distinct habitat ranges of the biological species Homo sapiens. This approach moves beyond dominant anthropocentric and technocratic frameworks in urban studies and reintroduces ecology as a fundamental analytical lens for understanding settlement systems. The methodological framework draws on the concepts of ecological niche, habitat range, ecotones, and historical contingency in species interactions. Humans are examined as a dominant ecosystem agent whose presence entails large-scale environmental transformation and intensive control over biotic and abiotic processes. The study demonstrates that spatial biodiversity patterns typical of natural ecosystems—lower diversity in core areas and higher diversity in peripheral and transitional zones—are also applicable to human settlements. Rural settlements are conceptualized as ecosystems of coexistence, formed within the resource capacity of local environments and characterized by a high degree of ecological delegation, in which essential ecosystem functions such as soil regeneration, biological regulation, microclimate maintenance, and resource renewal are performed by non-human agents. This configuration supports lower human energy expenditure, greater resilience, and multiple adaptive pathways. In contrast, cities are interpreted as anthropogenic ecosystems of control, where natural cycles are replaced by engineered systems, resources are externally supplied, and biodiversity is structurally limited. Reduced biodiversity is treated not as a side effect but as a functional condition of manageability and predictability. The article further examines global urbanization as a process generating ecosystems with a “bottleneck effect,” in which viability depends on the uninterrupted functioning of institutions, infrastructure, and technologies. Such systems exhibit limited adaptive capacity and weak internal self-regulation. The findings support the conclusion that Homo sapiens operates as a highly effective environmental engineer but a constrained manager of complex multispecies ecosystems due to excessive concentration of control and insufficient ecological delegation. Recognizing rural and urban settlements as fundamentally different ecosystem types is therefore essential for shaping sustainable spatial development strategies that account for biological limits alongside socio-economic objectives.

Recognition of biomolecular phenomena at interfaces is a key scientific challenge with fundamental and practical importance. In this work, we discover two structurally similar amino acids, glutamic acid (Glu) and aspartic acid (Asp), showing different biological functions, have a significant but distinct orientational coupling with liquid crystals (LCs). Combining experiments with density functional theory calculations, we reveal that Glu and Asp exhibit unique adsorption-desorption dynamics at the LC-aqueous interfaces, producing distinct macroscopic optical signals. These interfacial behaviors are specifically governed by pH condition of the aqueous solution because the pH variations cause significant changes in charge states of the amino acids and thus their intermolecular interactions with LCs. Additionally, the dynamics are also modulated by the presence of other biological molecules (e.g., bacterial byproducts of Salmonella lipopolysaccharide, Staphylococcus aureus lipoteichoic acid, and Escherichia coli lipopolysaccharide) forming complexes with the amino acids, which dramatically change the LC's optical response. Leveraging this specific recognition mechanism for the interfacial dynamics of biomolecules and their interactions with other biological species, we also demonstrate the practical LC systems that autonomously recognize and optically report Salmonella at trace concentrations (102 cfu/ml) within 1 min, significantly faster than the conventional methods (PCR and ELISA) requiring several hours.

Role of reactive oxygen species in polycystic ovary syndrome: signalling pathways, mechanisms, and traditional Chinese medicine treatment strategies.

Sex-based differences in toxicity after exposure to microplastics or nanoplastics in aquatic and terrestrial organisms: A systematic review.

Ratiometric detection of dopamine using NIR carbon dots and Alizarin red S-boronic acid complex: A competitive displacement approach.

Steccherinum and its allied genera represent a morphologically complex group of fungi within the Steccherinaceae. In this study, we investigated, through morphological and multigene phylogenetic analyses, the diversity of odontioid/hydnoid Steccherinum s.l. collected in Brazil. Culture studies were conducted to compare mycelial morphology and growth rates among species, and mating tests were performed to assess sexual compatibility among related taxa. In addition, divergence-time estimates for the Steccherinaceae were generated using a concatenated five-gene dataset to contextualize the evolutionary history of the group. Molecular data revealed eight well-defined neotropical lineages in Steccherinum, including S. larssonii, S. perparvulum, S. subochraceum, and five new species: S. bononiae, S. elegantissimum, S. molle, S. resinaceum, and S. undulatum. The five newly described taxa are morphologically very similar and differ only in subtle diagnostic traits. Two additional new species were identified in Cabalodontia: C. albofulva and C. brunnea. Furthermore, the new combinations C. lincangense and C. tenuissima are proposed based on the phylogenetic data. Phylogenetic analyses also demonstrated that S. perparvulum comprises a species complex with three distinct lineages. Mating tests between two of these lineages showed a lack of sexual compatibility, indicating that they represent separate biological species that cannot be distinguished morphologically. Mycelial culture studies also revealed generally similar morphology with variable growth rates among taxa. Divergence-time estimates indicate a crown age of approximately 86.4 Ma for the Steccherinaceae and a predominantly Cenozoic diversification, with Steccherinum originating in the Eocene. Our findings highlight significant cryptic diversity within Steccherinum in the Neotropics and provide new insights into the taxonomy and phylogeny of the genus.

A comprehensive list of the currently (as of 17 November 2025) valid taxa of bark and ambrosia beetles of the world (Curculionidae: Scolytinae) is presented, including all tribes, genera, species (6516), and subspecies. The high diversity of scolytine species, their biosecurity significance, and the rapidly advancing understanding of their phylogenetic relationships has resulted in decentralized and often incorrect usage of names. The list represents species names accepted and used in compliance with the International Code of Zoological Nomenclature and a consensus of name usage by the community of active systematists. Species names listed here are bona fide hypotheses of biological species, but not always of confirmed biological entities; instead, the list aims to provide a foundation for the subsequent taxonomic, biological, and phylogenetic work on species resolution, and for biodiversity data management. The list is presented as a formatted checklist, as well as a Darwin-core format enabling interpolation into biodiversity information systems. Two replacement names were needed to resolve homonyms, Hylastes woodi Johnson, nom. nov. (= Hylastes niger Wood, 1974) and Taphrorychus krivolutskayae Johnson, nom. nov. (= Dryocoetes aceris Krivolutskaya, 1968).

Sea spray aerosols (SSA) influence cloud properties by acting as cloud condensation nuclei (CCN) and ice-nucleating particles (INP), yet the factors controlling their climate-relevant properties remain poorly constrained. Current models often oversimplify SSA composition while neglecting the potential impact of wind speed variability. Here, we present the first direct measurements of SSA chemical mixing state under controlled wind speeds (11–18 m/s) in the Scripps Ocean-Atmosphere Research Simulator (SOARS). These experiments isolate the impact of wind speed on SSA chemical mixing state while limiting biological variability. Increasing wind speed drives a transition toward more homogeneous, salt-enriched SSA, increasing from 46% at 11 m/s to 80% at 18 m/s. Simultaneously, aerosolized coastal water pollutants decline sharply, while organic-enriched and biologically influenced particles increase, consistent with wind-driven disruption of the sea surface microlayer. As the size of SSA particles approaches the CCN-relevant range, we observe enhanced organic fractions, largely associated with sea salt. Moreover, the rise in larger accumulation mode SSA (>700 nm) enriched with biological species at high wind speeds is consistent with observed increases in INP concentrations in parallel SOARS measurements. This study demonstrates how wind-driven changes alter SSA mixing state, underscoring the need to incorporate these effects when modeling SSA climate properties and aerosol–cloud interactions.

The delimitation of biological species, i.e., deciding which individuals belong to the same species and whether and how many different species are represented in a dataset, is key to the conservation of biodiversity. Much existing work uses only genetic data for species delimitation, often employing some kind of cluster analysis. This can be misleading, because geographically distant groups of individuals can be genetically quite different even if they belong to the same species. We investigate the problem of testing whether two potentially separated groups of individuals can belong to a single species or not, based on genetic and spatial data. Already existing methods such as the partial Mantel test and jackknife-based distance-distance regression are considered. New approaches, i.e., an adaptation of a mixed effects model, a bootstrap approach, and a jackknife version of partial Mantel, are proposed. All these methods address the issue that distance data violate the independence assumption for standard inference regarding correlation and regression. A standard linear regression is also considered. The approaches are compared on simulated meta-populations generated with the software packages SLiM and GSpace that can simulate spatially explicit genetic data at an individual level. Simulations show that the new jackknife version of the partial Mantel test provides a good compromise between power and respecting the nominal type I error rate. Mixed-effects models have larger power than jackknife-based methods, but in some situations they display type I error rates above the significance level. An application on brassy ringlets concludes the paper.