Search Results (34)

Ericoid mycorrhizal fungi (EMF) enhance plant fitness and metabolic regulations in nutrient-poor soils, though the mechanisms diving these interactions require further elucidation. This study investigated the physiological and metabolic responses of blueberry seedlings following 2- and 3-weeks inoculation with Oidiodendron maius H14. The results indicated that EMF could significantly increases plant biomass, improve the accumulation of osmoregulatory substances in leaves. Additionally, the colonization rate of EMF are 26.18% and 30.22% after 2- and 3-weeks, respectively. The Metabolomics analysis identified 758 (593 up- and 165 down-regulated) and 805 (577 up- and 228 down-regulated) differential metabolites in roots at 2- and 3-weeks inoculation with O. maius H14, respectively. KEGG pathway annotation revealed that O. maius H14 triggered various amino acid metabolism pathways, including tryptophan metabolism and arginine and proline metabolism. These findings suggested that O. maius H14 stimulated root-specific biosynthesis of growth-promoting compounds and antimicrobial compounds. Concomitant downregulation of stress-associated genes and upregulation of glutamine synthetase suggest EMF modulates host defense responses to facilitate symbiosis. Thus, our results demonstrated that O. maius H14 orchestrates a metabolic reprogramming in blueberry roots, enhancing growth and stress tolerance through coordinated changes in primary and specialized metabolism, which could inform strategies for improving symbiosis and metabolic engineering in horticultural practices. Full article

Among marine organisms, baleen whale species like the humpback whale (Megaptera novaeangliae) are a case for which individual-based models are necessary to study population changes because individual trait variabilities predominate over average demographic rates to govern population dynamics. These models require quantification of individual organisms’ dynamics with respect to local conditions, which implies optimal strategy frameworks cannot be used. Instead, to quantify how individuals perform according to the environmental conditions they encounter, we formulated a model linking individual mechanical characteristics of swimming and diving with their aerobic metabolism and behavior. The model simulates the dynamics of swimming and diving for the reported range of whale sizes (1000 to 50,000 kg). Additional processes simulate foraging events including rapid accelerations and water engulfment, which modifies whale shape, weight and drag. Simulations show how the energy cost of swimming at equilibrium increases geometrically with velocity and linearly with mass. The duration and distance covered under apnea vary monotonically with mass but not with velocity; hence, there is a positive mass-dependent optimal velocity that maximizes the distance and duration of apnea. The dive limit was explored with a combination of the physiological state, mechanical force produced and distance to return to surface. This combination is imposed as an inequality constraint on the whale individual. The inequality constraint, transformed as a multi-layer perceptron, which continuously processes information about oxygen, depth and relative velocity, provides the whale individual with autonomous decision-making about whether or not to continue the dive. The results also highlight where missing metabolic information is needed to simulate the dynamics of a population of autonomous individuals at the scale of the Global Ocean. Full article

The Atlanto-Mediterranean sea cucumber Holothuria tubulosa is a species of great ecological and commercial importance, making it a primary target for collection in the Mediterranean region. This study investigated the reproductive biology of H. tubulosa (Gmelin, 1793) in a coastal area of the Central Aegean Sea (Eastern Mediterranean) over a one-year period, from June 2021 to May 2022. Monthly sampling was conducted via dives at depths up to 10 m, alongside the recording of environmental and biometric data. Histological analysis revealed a synchronous annual reproductive cycle, with gonadal maturation beginning in April and peak sexual maturity observed in July and August, followed by a single spawning event from August to September. The sex ratio was 1:1.31 (male: female), and the size at first maturity was 255.3 mm. These findings provide essential insights into the reproductive physiology of H. tubulosa and further contribute to the development of sustainable stock management strategies for sea cucumbers in the Hellenic Seas. Full article

We investigated the genetic and environmental variables determining the glucosinolate (GSL) content of cruciferous vegetables and the implications for cancer prevention. The enzyme myrosinase hydrolyzes GSLs, which are sulfur-containing chemicals found mostly in cruciferous vegetables, producing isothiocyanates (ITCs), which are physiologically active molecules. GSL breakdown products have considerable anti-carcinogenic, antioxidant, and anti-inflammatory capabilities, making them vital to human health. The review dives into genetic heterogeneity among cruciferous species, the importance of individual genes in GSL manufacturing, and breeding techniques for increasing GSL content. It also examines how environmental variables like soil type, pH, plant, nutrient availability, and temperature affect GSL levels. This report also covers the function of GSLs in plant defense, their bioavailability in humans, and their mechanisms in cancer prevention, emphasizing the chemicals’ potential for lowering cancer risk through cruciferous vegetable consumption. The findings highlight the necessity of optimizing both genetic and environmental variables required to increase the nutritional content and medicinal potential of cruciferous vegetables. Full article

Oxidative stress (OS) occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body’s antioxidant defenses, causing damage to lipids, proteins, and DNA. In marine mammals, physiological adaptation to aquatic life conditions, such as prolonged and repeated dives resulting in cycles of hypoxia followed by reperfusion, is associated with increased production of ROS. This study examines the relationship between oxidative stress, muscular stress, and metabolic damage in the blood serum of eleven captive bottlenose dolphins (Tursiops truncatus), six males and five females. This relationship is investigated using oxidative stress markers (d-ROMs, OXY, and Oxidative Stress index, OSi) and biochemical parameter measurements, including glucose (GLU), aspartate aminotransferase (AST), creatine kinase (CK), and lactate dehydrogenase (LDH). Pearson’s sex correlation was performed, and males exhibited significantly higher pro-oxidant levels than females, suggesting a potential protective role of female hormones. Also, a positive correlation between pro-oxidants and antioxidants has been observed in relation to age, as older dolphins produced more ROS but also exhibited higher antioxidant capacity, likely to compensate for oxidative damage. Results show no significant correlation between biochemical parameters and oxidative stress markers. However, a moderately positive correlation between LDH and antioxidant (OXY) capacity was observed (r = 0.458), suggesting a possible association between tissue turnover and antioxidant defenses. The results indicate that the biochemical markers analyzed are not strong predictors of oxidative stress in bottlenose dolphins. However, the correlation between LDH and antioxidant capacity suggests that tissue turnover may affect antioxidant defenses. This is a preliminary study, and further research is needed to clarify these relationships in order to better understand physiological adaptations in dolphins and their implications for management, health, and welfare. Full article

Bionic paddling robots, as a novel type of underwater robot, demonstrate significant potential in the fields of underwater exploration and development. However, current research on bionic paddling robots primarily focuses on the motion mechanisms of large organisms such as frogs, while the exploration of small and highly agile bionic propulsion robots remains relatively limited. Additionally, existing biomimetic designs often face challenges such as structural complexity and cumbersome control systems, which hinder their practical applications. To address these challenges, this study proposes a novel diving-beetle-inspired paddling robot, drawing inspiration from the low-resistance physiological structure and efficient paddling locomotion of diving beetles. Specifically, a passive bionic swimming foot and a periodic paddling propulsion mechanism were designed based on the leg movement patterns of diving beetles, achieving highly efficient propulsion performance. In the design process, a combination of incomplete gears and torsion springs was employed, significantly reducing the driving frequency of servos and simplifying control complexity. Through dynamic simulations and experimental validation, the robot demonstrated a maximum forward speed of 0.82 BL/s and a turning speed of 18°/s. The results indicate that this design not only significantly improves propulsion efficiency and swimming agility but also provides new design insights and technical references for the development of small bionic underwater robots. Full article

The glymphatic system, an analog of the peripheral lymphatic system in the brain, and the meningeal lymphatic system are critical to central nervous system health. The glymphatic system functions to distribute cerebrospinal fluid and important compounds throughout the brain and to remove metabolic waste. The flow of cerebrospinal fluid through this system is affected by changes in cerebral blood flow, intracranial pressure, and vascular tone. Cetaceans experience profound cardiorespiratory alterations while diving that can directly affect cerebrospinal fluid and blood flow and, thus, glymphatic function. Our goal was to investigate glymphatic and lymphatic system structures, including perivascular spaces, aquaporin-4 water channels, meningeal lymphatic, and dural venous sinus vessels in the common dolphin (Delphinus delphis), using immunofluorescent labeling, histochemical staining, and postmortem computed tomography (CT) angiography. We highlight perivascular spaces and aquaporin-4 water channels surrounding blood vessels in the parenchyma and demonstrate evidence of meningeal lymphatic vessels and associated dural venous sinuses. These results demonstrate that common dolphins possess the key anatomical structures required for functional glymphatic and meningeal lymphatic systems. Future studies can build upon these anatomical discoveries to study the function and role of these systems in brain health in this species. Full article

Recent studies have shown that both facial immersion and head-out water immersion up to the chest (HOIC) positively influence cardiac vagal activity, as indexed non-invasively through vagally mediated heart rate variability (vmHRV). While facial immersion activates the diving reflex, HOIC induces effects via hydrostatic pressure, each engaging distinct physiological mechanisms. This study aims to investigate whether combining facial immersion with HOIC results in an additional increase in vmHRV. In total, the vmHRV [log10RMSSD] of 37 participants (14 females, M_age = 23.8; SD_age = 4.4 years) was assessed under two conditions, with resting and recovery measurements taken before and after each condition. The first condition involved HOIC alone (M = 1.97, SD = 0.27), followed by HOIC combined with facial immersion (M = 1.87, SD = 0.29). HOIC alone significantly increased RMSSD compared to baseline (p < 0.001); however, no additional increase was observed when facial immersion was added (p = 0.436). This suggests that, while HOIC effectively increases vmHRV, the addition of facial immersion does not provide any further enhancement under the conditions tested. Potential methodological limitations, such as the absence of breath holding, variability in immersion depth, and the use of thermoneutral water temperatures, may have influenced the outcomes and warrant further investigation. Full article

This letter addresses errors in the statistical analysis found in a paper addressing pulmonary diffusing capacity and decompression sickness. Our re-analysis could not confirm any of the significant statistical contrasts described for the bubble data, invalidating the speculation on the relationships between bubble scores and decompression sickness. Full article

SCUBA diving poses risks due to pressure changes during descent (compression) and ascent (decompression). Decompression sickness (DCS) occurs due to gas bubble formation as the pressure decreases, causing joint pain, numbness, dizziness, or even paralysis and death. Immediate treatment involves 100% oxygen to help eliminate inert gases and hyperbaric oxygen therapy (HBOT), which is essential to reduce gas emboli formation and inflammation, thus improving symptoms. We evaluated oxy-inflammation biomarkers in the saliva and urine of nine subjects pre- and post-technical dive on the Haven wreck (GE, Italy). A case of DCS occurred during the dive. The injured diver was treated immediately with O₂ and transported to the hyperbaric center of “ASST Ospedale Ca Granda” in Milan. He was treated following the U.S. Navy Treatment Table 5 at 2.8 ATA and the day after with Table 15 at 2.4 ATA. Venous blood and urine samples were collected before and after each HBO treatment. Our study shows that dive increased oxy-inflammation biomarkers (ROS +126%; lipid peroxidation +23%; interleukins-6 +81%, -1β +19%, and TNFα +84%) and nitric oxide metabolites levels (+36%). HBOT after a DCS episode reduced oxidative stress, lowering the very high marker of lipid peroxidation (8-iso-PGF2α), and inhibited inflammatory interleukins. Overall, HBOT improved physiological responses in the diver affected by DCS. Full article

This review examines the relationship between the physiological demands of diving and premature ventricular complexes (PVCs) in divers. In the general population, some individuals have a greater tendency to experience PVCs, often without awareness or a clear understanding of the triggering factors. With the increasing availability and popularity of both scuba and apnoea diving, more people, including those with a predisposition to PVCs, are engaging in these activities. The underwater environment, with its unique stressors, may increase the risk of arrhythmogenic events, particularly PVCs. Here, we review the prevalence, pathophysiology, and aggravating factors of PVCs in divers, emphasising the need for a comprehensive cardiovascular assessment. Evidence suggests a higher prevalence of PVCs in divers compared with the general population, influenced by factors such as age, dive depth, gas bubbles, cold water immersion, pre-existing cardiovascular diseases, and lifestyle factors. The change in environment during diving could potentially trigger an increased frequency of PVCs, especially in individuals with a pre-existing tendency. We discuss diagnostic strategies, management approaches, and preventive measures for divers with PVCs, noting that although guidelines for athletes can be adapted, individual assessment is crucial. Significant knowledge gaps are identified, highlighting the need for future research to develop evidence-based guidelines and understand the long-term significance of PVCs in divers. This work aims to evaluate potential contributing factors to PVCs in divers and identify individuals who may be at higher risk of experiencing major adverse cardiovascular events (MACEs). This work aims to improve diver safety by promoting collaboration between cardiologists and diving medicine specialists and by identifying key areas for future investigation in this field. This work aims to improve the safety and well-being of divers by understanding the cardiovascular challenges they face, including pressure changes, cold water immersion, and hypoxia. We seek to elucidate the relationship between these challenges and the occurrence of PVCs. By synthesising current evidence, identifying knowledge gaps, and proposing preliminary recommendations, we aim to encourage collaboration between cardiologists and diving medicine specialists to optimise the screening, management, and risk stratification of PVCs in the diving population. Full article

Lower limb muscle fatigue is the main reason for withdrawal from diving. Therefore, this study aimed to determine the local muscle oxygen saturation and hemoglobin concentration in the vastus lateralis muscle during different freediving disciplines. One freediver participated in this study, and his chronological age was 40 years, body mass 75.0 kg, body height 184.0 cm, and body fat 13.7%. The participant has been practicing freediving for 6 years. The variables in this study included anthropometric indices, heart rate, and muscle oxygen dynamics parameters (SmO₂ (oxygen muscle saturation) and tHb (total hemoglobin)). The variables were measured during five diving disciplines: static apnea, bifin, dynamic no fins (DNF), monofin, and sneaking. Measurements were performed during intensive training/competition during the diving season in August 2023. The results of this study showed that when oxygen starts to decrease during the dive, the tHb increases. Furthermore, the times at which maximal tHb and minimal SmO₂ were achieved are also shown. These parameters occurred at almost the same time across all disciplines: static (SmO₂, 142; tHb, 150 s), bifin (SmO₂, 153; tHb, 148 s), DNF (SmO₂, 162; tHb, 178 s), monofin (SmO₂, 96; tHb, 94 s), and sneaking (SmO₂, 212; tHb, 228 s). Also, differences in tHb and SmO₂ were present between diving disciplines. In particular, the highest increase in tHb was present in bifin (0.0028 AU/s), whereas monofin showed a decrease (−0.0009 AU/s). On the other hand, the highest desaturation was seen in bifin (−0.87%/s) and the lowest in sneaking (−0.29%/s) These findings emphasize the physiological characteristics of freedivers engaging in different freediving disciplines that influence muscles during the dive. Such responses could be observed through a concurrent hypoxia/hypercapnia and a transient reduction in the Fahraeus effect. Full article

Time-series experiments are crucial for understanding the transient and dynamic nature of biological phenomena. These experiments, leveraging advanced classification and clustering algorithms, allow for a deep dive into the cellular processes. However, while these approaches effectively identify patterns and trends within data, they often need to improve in elucidating the causal mechanisms behind these changes. Building on this foundation, our study introduces a novel algorithm for temporal causal signaling modeling, integrating established knowledge networks with sequential gene expression data to elucidate signal transduction pathways over time. Focusing on Escherichia coli’s (E. coli) aerobic to anaerobic transition (AAT), this research marks a significant leap in understanding the organism’s metabolic shifts. By applying our algorithm to a comprehensive E. coli regulatory network and a time-series microarray dataset, we constructed the cross-time point core signaling and regulatory processes of E. coli’s AAT. Through gene expression analysis, we validated the primary regulatory interactions governing this process. We identified a novel regulatory scheme wherein environmentally responsive genes, soxR and oxyR, activate fur, modulating the nitrogen metabolism regulators fnr and nac. This regulatory cascade controls the stress regulators ompR and lrhA, ultimately affecting the cell motility gene flhD, unveiling a novel regulatory axis that elucidates the complex regulatory dynamics during the AAT process. Our approach, merging empirical data with prior knowledge, represents a significant advance in modeling cellular signaling processes, offering a deeper understanding of microbial physiology and its applications in biotechnology. Full article

Diver training improves physical and mental fitness, which can also benefit other sports. This study investigates the effect of eight weeks of static apnea training on maximum apnea time, and on the physiological parameters of runners, swimmers, and sedentary participants, such as forced vital capacity (FVC), minimum heart rate (HR), and oxygen saturation (SpO₂). The study followed 19 participants, including five runners, swimmers, sedentary participants, and four competitive divers for reference values. The minimum value of SpO₂, HR, maximum duration of apnea, and FVC were measured. Apnea training occurred four times weekly, consisting of six apneas with 60 s breathing pauses. Apnea duration was gradually increased by 30 s. The measurement started with a 30 s apnea and ended with maximal apnea. There was a change in SpO₂ decreased by 6.8%, maximum apnea length increased by 15.8%, HR decreased by 9.1%, and FVC increased by 12.4% for the groups (p < 0.05). There were intra-groups changes, but no significant inter-groups difference was observed. Eight weeks of apnea training improved the maximum duration of apnea, FVC values and reduced the minimum values of SpO₂ and HR in all groups. No differences were noted between groups after training. This training may benefit cardiorespiratory parameters in the population. Full article

Underwater activities are characterized by an imbalance between reactive oxygen/nitrogen species (RONS) and antioxidant mechanisms, which can be associated with an inflammatory response, depending on O₂ availability. This review explores the oxidative stress mechanisms and related inflammation status (Oxy-Inflammation) in underwater activities such as breath-hold (BH) diving, Self-Contained Underwater Breathing Apparatus (SCUBA) and Closed-Circuit Rebreather (CCR) diving, and saturation diving. Divers are exposed to hypoxic and hyperoxic conditions, amplified by environmental conditions, hyperbaric pressure, cold water, different types of breathing gases, and air/non-air mixtures. The “diving response”, including physiological adaptation, cardiovascular stress, increased arterial blood pressure, peripheral vasoconstriction, altered blood gas values, and risk of bubble formation during decompression, are reported. Full article