Search Results (538)

Regulatory T cells (Tregs), particularly their phenotypically distinct subpopulations, are critical for the establishment of maternal immune tolerance during embryo implantation. Despite advances in assisted reproductive technologies, implantation failure remains a frequent and often unexplained clinical challenge. Variations in Treg frequency and phenotype have been proposed to influence implantation success, particularly under differing hormonal conditions. This study aimed to investigate peripheral blood Treg levels and their subpopulations on the day of blastocyst transfer in both stimulated in vitro fertilization (IVF/ICSI) cycles involving controlled ovarian hyperstimulation (COH) and true natural cycles with frozen embryo transfer (FET), and to examine their associations with systemic hormone levels and anti-Müllerian hormone (AMH). A prospective observational study was conducted including women undergoing IVF/ICSI with fresh embryo transfer (ET) and women undergoing natural cycle FET. Peripheral blood samples were collected on the day of ET and analyzed using 13-colour flow cytometry, enabling detailed subdivision of Tregs into multiple subpopulations based on the expression of differentiation and chemokine markers, including CXCR5. In addition, because common $\gamma$-chain cytokines may influence pregnancy success by modulating the balance between suppressive Treg and non-Treg subsets, intracellular STAT5 signaling was assessed using phospho-specific flow cytometry. Serum estradiol, progesterone, FSH, LH, and AMH levels were measured in parallel. Significant differences were observed in Treg subpopulation distributions between women who conceived and those who did not. Higher frequencies of naïve CXCR5⁻ Tregs were associated with clinical pregnancy, independent of age, and correlated with serum progesterone levels. Moreover, both naïve Treg frequency and enhanced IL-7-dependent STAT5 signaling in naïve Tregs from women undergoing COH were associated with AMH levels, suggesting a link between ovarian reserve and Treg homeostasis mediated by signal transducer and activator of transcription 5 (STAT5) signaling. In conclusion, Treg subpopulations, particularly CXCR5⁻ naïve Tregs, appear to play a central role in implantation success following ET. Their distribution differs between stimulated and natural cycles and is influenced by systemic progesterone levels and STAT5 signaling. These findings suggest that peripheral Treg profiling may represent a potential biomarker of implantation competence and could inform personalized approaches in assisted reproduction. Full article

The post-implantation phase of mammalian development is crucial yet challenging to study due to ethical and technical constraints, particularly in humans. Recent revolutionary advances in extended in vitro culture systems for mammalian embryos now offer unprecedented windows into this developmental “black box”. This review synthesizes how these platforms, alongside stem cell-derived embryo models, are transforming our ability to model early human development in a dish. We detail the technological evolution from two-dimensional (2D) to three-dimensional (3D) cultures that support mouse, non-human primate, and human embryos through key stages of implantation and gastrulation, recapitulating events like lineage specification and axial patterning. Furthermore, we explore how these models serve as powerful tools for investigating the etiology of early pregnancy failure, screening for developmental toxicity of pharmaceuticals, and deciphering the molecular pathogenesis of birth defects. By bridging fundamental embryology with clinical and pharmacological applications, these innovative models herald a new era in biomedical research, holding significant promise for advancing reproductive medicine and regenerative strategies. Full article

This study characterizes the chemical defense system of the invasive longhorn beetle Aromia bungii, a destructive pest of Prunus trees, addressing the limited understanding of chemical defensive mechanisms in Cerambycidae. High-speed cameras, environmental scanning electron microscopy (ESEM), dissection, and micro-CT imaging were used to investigate defensive behavior, and the structure of the defense system, in this beetle. Both sexes of A. bungii possess a pair of triangular, sac-like defensive glands symmetrically located in the metathorax, attached to the metasternum. Upon mechanical stimulation, white liquid defensive substances are rapidly ejected through a pair of slit-shaped openings (~200 µm) at the metasternum corners, without gland eversion, reaching over 50 cm. The average weight of substances ejected in first sprays was 7.95 ± 0.79 mg for females and 8.62 ± 2.13 mg for males (mean ± se), with no significant difference between sexes. However, the weight in second sprays after 10 days was significantly lower, at 2.93 ± 0.54 mg for females and 2.22 ± 0.40 mg for males (mean ± se), suggesting that the beetles cannot re-synthesize the substances soon after spray. The weight of ejected substances had no correlation with beetle body weight. Our findings represent the first detailed morphological and functional description of a chemical defense system in Cerambycidae, revealing a specialized metasternal gland and spray mechanism. The substantial but likely non-renewable defensive substances reflect an adaptive trade-off in energy allocation between reproduction and defense in this species that exhibits high fecundity but a short lifespan at the adult stage. Full article

Microplastics (MPs) are considered to be dominant agents responsible for serious contamination in environmental and biological systems. Despite a huge increase in research on these contaminants, there are still considerable uncertainties and progress to be made on the exposure pathways of biological systems, modes of detection, and toxicity assessments. Therefore, developing a critical review of MPs is crucial due to growing evidence of their harmful effects on human health. In the current review, we aim to emphasize the potential toxic effects of MPs on different biological systems in humans, the mechanisms of their toxic effects, and gaps in our knowledge on risk assessment. Importantly, we focus on the risks posed by MPs for fetuses and child health. To ensure methodological rigor, the current review follows the PRISMA guidelines, explicitly detailing the literature search strategy and inclusion/exclusion criteria. The present review summarizes potential sources of MP generation, exposure pathways, quantitative analyses of dietary exposure, estimated daily intake, particle/leachate toxicity evidence, detection in different human organs, and potential toxic effects. MPs cause toxicity in several biological systems in humans, such as the gastrointestinal, nervous, hepatic, endocrine, respiratory, and reproductive systems. In addition, these particles are known to cause oxidative stress, alter metabolism, and affect gut microflora and gastrointestinal functions. Importantly, the current review also discusses the challenges encountered in conducting risk assessments for MPs and the approaches for counteracting these challenges. Finally, the review concludes by recommending future research directions in terms of counteracting the toxic effects of MPs on human health. Full article

Intraspecific brood parasitism (IBP), where one female lays eggs in another’s nest, is considered rare in raptors, including typically monogamous and solitary or semi-colonial falcons. The Lesser Kestrel (Falco naumanni) is a colonial falcon with a usual clutch size of one to five eggs, yet two independent cases of anomalously large clutches consistent with suspected IBP are described from long-term studies in Greece and Israel. In central Greece (Armenio; 39°29′ N, 22°41′ E), a nest box colony monitored since 1998 produced a clutch of eight unhatched eggs in 2017; egg volumes formed two statistically distinct groups (V₁ = 850.74 ± 27.72 vs. V₂ = 926.78 ± 18.87 mm³; t = 4.146, p = 0.006), suggestive of contributions from two females. In Israel (Alona District; 32°35′ N, 35°05′ E), a nest under an asbestos roof contained a mixed clutch of eight eggs laid over two seasons (2003–2004), with four new eggs added to four unhatched eggs from the previous year; only one egg hatched and the chick was subsequently predated by a Little Owl (Athene noctua). Given the species’ typical clutch size and the occurrence of double clutches, these cases are interpreted as rare instances of parasitic egg-laying. Their extreme rarity—only one event over more than 20 years of monitoring ~120 pairs annually in Greece—underscores how uncommon IBP appears to be in Lesser Kestrels and how easily such events may be overlooked without intensive, long-term monitoring. The results emphasize the need to combine detailed field observations with molecular parentage analyses, quantify IBP frequency, and clarify the ecological and evolutionary relevance of alternative reproductive strategies in this and other colonial raptors. Full article

We examine a Szász–Mirakyan–Durrmeyer type operator that reproduces the functions 1 and $e^{2ax}$ for a fixed parameter $a>0.$ While its exponential reproduction property has been described in the classical literature, the effect of exponential weights on its approximation behavior has not been studied. In this work, we provide a detailed analysis of the operator in weighted spaces and show that combining exponential reproduction with weighted norms improves the approximation behavior for exponentially growing functions. We also prove that the corresponding sequence of operator norms remains uniformly bounded for a family of exponential weights, ensuring the stability of the operators in the weighted framework. Moreover, we establish new Korovkin-type approximation theorems involving weighted convergence and obtain sharp uniform error estimates in the presence of exponential weights. These results extend the classical theory to weighted exponential settings and highlight several quantitative features that do not arise in the classical case. Full article

Reintroductions are essential in wildlife conservation, but their success depends not only on demographic outcomes such as survival and reproduction, but also on behavioral adjustments that determine integration into the wild. The Grey Crowned Crane (Balearica regulorum), an endangered species, has suffered dramatic declines due to habitat loss, disturbance, and illegal capture. In Rwanda, a large-scale amnesty rescued 242 cranes from captivity, with 166 rehabilitated and released into Akagera National Park. This study used GPS-GSM telemetry to investigate post-release movement of reintroduced captive-rescued cranes in comparison with wild individuals. Twenty-one cranes (10 reintroduced, 11 wild) were tracked for 5–1118 days, with 15 individuals meeting criteria for detailed analyses. Reintroduced cranes exhibited reduced dispersal, with only 2 of 7 dispersing compared to 7 of 9 wild cranes, and typically after much longer residence at the release site. Reintroduced cranes also had smaller maximum displacements (median 8.4 km) and smaller home ranges (median 3.3 km²) relative to those of wild cranes (median 24.0 km and median 22.6 km², respectively). These findings suggest that supplemental feeding and extended captivity (2 days to 10 years) of reintroduced cranes strongly influenced their high site fidelity and movement patterns. While limited dispersal may benefit short-term survival, long-term monitoring of survival, reproduction, and demographic trends is critical for assessing whether reintroduction achieves population recovery. Full article

Controlled environment agriculture technologies are traditionally applied to higher plants to enhance growth and cultivation periods, but such a concept has seldom been applied to seaweed aquaculture. A new dimension has been opened, wherein preliminary investigations in Ulva ohnoi revealed that continuous exposure (24 h) of light modulates chlorophyll-a fluorescence, carbohydrate content, and biochemical composition affecting the daily growth rate. DGR (daily growth rate) increased 2.6 times under continuous illumination for 24 h compared to the 12 h L/D photoperiod. Mg and carbohydrate contents were raised by 1.1 and 1.2 times, respectively, under continuous illumination. DGR formed a strong positive correlation with carbohydrate, protein, carotenoid, chlorophyll-a fluorescence, C, H, and Mg levels. A short cultivation cycle (15 days) was proposed to enable a consistent, continuous high growth and to avoid the induction of reproduction. The feedstock demand for bio-products, aquaculture feed, biomaterials, functional food, and food additives is registering unprecedented feedstock demand for Ulva. However, further detailed studies are desired to understand the seasonality and economic viability of scaling up this technique for commercial implementation. Full article

The paper assesses brown seaweed diversity following the catastrophic events of the 2010 Deepwater Horizon (DWH) oil spill in offshore deep bank habitats at 45–90 m depth in the northwestern Gulf of Mexico, and their potential regeneration and recovery in the region. Innovative approaches to expeditionary and exploratory research resulted in the discovery, identification, and classification of brown seaweed diversity associated with rhodoliths (free-living carbonate nodules predominantly accreted by crustose coralline algae). Whereas the rhodoliths collected in situ at our research sites pre-DWH were teeming with brown algae growing on their surface, post-DWH they looked dead, bare, and bleached. These post-DWH impacts appear long-lasting, with little macroalgal growth recovery in the field. However, these apparent “dead” rhodoliths collected post-DWH at banks offshore Louisiana showed macroalgal regeneration starting within three weeks when placed in microcosms in the laboratory, with 19 brown algal species emerging from the bare rhodoliths’ surface. Some taxa corresponded to new records for the GMx (genus Cutleria and Dictyota cymatophila). Padina vickersiae is resurrected from synonymy with P. gymnospora. Reproductive sori evidence is presented for Lobophora declerckii. A detailed nomenclatural list, morphological plates, and phylogenetic/barcoding trees of brown seaweed that emerged from rhodoliths’ surfaces in laboratory microcosms are provided. These findings provide key molecular and morphological insights that reinforce species boundaries and highlight the significance of mesophotic rhodolith beds as previously overlooked reservoirs of cryptic brown algal diversity. Full article

Classical branching-process theory, developed by Galton and Watson in the nineteenth century and later refined by Fisher and Haldane, provides the formal framework for quantifying the fate of new mutants, new viral and bacterial pathogens, new colonization of invasive species, etc. It is a powerful tool to quantify and predict the effect of differential reproductive success on the speciation potential of evolutionary lineages. Here, I revisit the conceptual framework of the branching process, detail its mathematical development over time, tie up a few historical loose strings, illustrate the calculation of the exact extinction probability for the Poisson-distributed reproductive success with the Lambert function (which is often missing in the ecological and evolutionary literature), and highlight the potential applications of the branching process in modern ecology and evolutionary biology, especially in deriving the extinction probability and extinction time. I also highlight a few misconceptions about human demography in the US that can be readily dismissed by applying probability tools such as branching processes. Full article

Ovulation is a critical event in mammalian reproduction, a complex process that involves the release of a mature oocyte from the ovaries for fertilization. Hormonal shifts are the driving force of the ovulation cycle; however, several other factors are able to fine-tune the occurrence of follicular rupture. Prior to the follicular rupture, the pre-ovulatory luteinizing hormone (LH) surge triggers a self-generating local inflammatory and redox cascade, which is responsible for the release of several inflammatory and redox signaling mediators. Eicosanoids are one of the key regulators of the initiation of the local inflammation within the follicle, while the balance of reactive oxygen species and antioxidants is fundamental to maintaining the physiologically coordinated redox state during the ovulation process. In this review, we aim to provide a summary of the human menstrual and rat estrus cycles and demonstrate the LH-induced inflammatory and redox cascade involved in follicle rupture through the details of lipid-derived and redox signaling mediators. Full article

This narrative review aims to summarize, synthesize, and organize current knowledge on the adaptation of sheep and goats to stressful environments and to discuss how these adaptations contribute to food security in vulnerable communities. A structured search of Web of Science, Scopus, PubMed, and Google Scholar was conducted using combinations of terms related to sheep and goats, harsh environments (e.g., arid and semi-arid regions, heat stress, water restriction, poor-quality forage), and adaptation or resilience, combined with Boolean operators. A total of 1718 research publications were found, of which 86 were retained as the most relevant because they provided direct and detailed evidence on anatomical, physiological, digestive–microbiome, behavioral, and genomic adaptations of sheep and goats to stressful environments. The selected studies describe a wide range of phenotypic and integumentary traits, thermoregulatory and endocrine responses, digestive and microbial adjustments, behavioral strategies, and genomic signatures that, together, allow small ruminants to maintain basic functions, reproduction, and production under conditions of climatic and nutritional stress. Evidence from these studies also highlights how adaptive traits support herd productivity, economic stability of households, and the sustainable use of natural resources in regions where climatic variability and resource scarcity are common. Overall, the synthesis presented here underscores the importance of conserving and strategically using locally adapted sheep and goat breeds, incorporating resilience-related traits into breeding and management programs, and prioritizing further research on genomic, microbiome, and epigenetic mechanisms that underpin adaptation to harsh environments. Full article

Rainfall simulators are crucial devices in erosion research, enabling the controlled reproduction of precipitation characteristics for both laboratory and field investigations. This study presents a comprehensive characterization of a rainfall simulator originally designed to assess the erosive effects of precipitation on heritage surfaces. The simulator, installed at the University of León, was evaluated using volumetric methods and disdrometric techniques, employing a Parsivel² optical disdrometer. Simulations were conducted with a falling height of 10 m and high-intensity rainfalls. Spatial uniformity was assessed through thematic mapping and the Christiansen Uniformity (CU) coefficient, revealing limited uniformity across the full wetted area, but an improved performance within the central zone (CU up to 80%). Disdrometric data provided detailed insights into drop size and velocity distributions, enabling the estimation of rainfall intensity, kinetic energy, and momentum, as well as the spatial uniformity of the energetic parameters. Empirical models to estimate the raindrop’s fall velocity were tested against disdrometric measurements, confirming the simulator’s ability to generate rainfall with velocity characteristics comparable to those of natural precipitation. Moreover, the findings underscore the importance of integrating multiple measurement approaches to enhance the reliability and accuracy of rainfall simulator characterization. Full article

Spermatogenesis in passerine birds remains poorly characterized. Previous studies focused on the steps of spermiogenesis, while a detailed staging of the seminiferous epithelium cycle is still lacking for this order. In this study, we provide the first comprehensive histological characterization of spermatogenesis in a model passerine species, the zebra finch. We defined ten distinct steps of spermiogenesis based on acrosomal and nuclear morphology of spermatids in Periodic acid–Schiff-stained histological sections. Using this classification, we further defined seven stages of the seminiferous epithelium, encompassing cytological features associated with the programmed DNA elimination, which is unique to passerines. Our analysis revealed that seminiferous tubules of the zebra finch exhibit a mosaic organization typical of all birds examined so far. However, in this species, most stages were characterized by the presence of spermatids at three developmental steps, in contrast to the one to two steps typical of non-passerine birds. To facilitate future comparative studies, we developed a flowchart for determining the stages of the seminiferous epithelium cycle. This work establishes an essential histological framework for future research in reproductive biology of the zebra finch and other passerine species. Full article

The Cutting Development Chamber (CDC) design is presented as an innovative solution to crucial human challenges, such as food and plant medicinal production. Unlike conventional propagation chambers, the CDC is a much more comprehensive research tool, specifically designed to optimize plant reproduction from cuttings. It maintains precise control over humidity, temperature, and lighting, which are essential parameters for plant development, thus maximizing the success rate, even in difficult-to-propagate species. Its modular design is one of its main strengths, allowing users to adapt the chamber to their specific needs, whether for research studies or for larger-scale propagation. The most distinctive feature of this chamber is its ability to collect detailed, labeled data, such as images of plant growth and environmental parameters that can be used in artificial intelligence tasks, which differentiate it from chambers that are solely used for propagation. A study that validated and calibrated the chamber design using cuttings of various species demonstrated its effectiveness through descriptive statistics, confirming that CDC is a powerful tool for research and optimization of plant growth. In validation experiments (Aloysia citrodora and Stevia rebaudiana), the system generated 6579 labeled images and 67,919 environmental records, providing a robust dataset that confirmed stable control of temperature and humidity while documenting cutting development. Full article