Comparative Physiological Studies Research Articles

Codonopsis pilosula seedling drought- responsive key genes and pathways revealed by comparative transcriptome.

Codonopsis pilosula (Campanulaceae) is a traditional herbal plant that is widely used in China, and the drought stress during the seedling stage directly affects the quality, ultimately impacting its yield. However, the molecular mechanisms underlying the drought resistance of C. pilosula seedlings remain unclear. Herein, we conducted extensive comparative transcriptome and physiological studies on two distinct C. pilosula cultivar (G1 and W1) seedlings subjected to a 4-day drought treatment. Our findings revealed that cultivar G1 exhibited enhanced retention of proline and chlorophyll, alongside a marked elevation in peroxidase activity, coupled with diminished levels of malondialdehyde and reduced leaf relative electrolyte leakage compared with cultivar W1. This suggested that cultivar G1 had relatively higher protective enzyme activity and ROS quenching capacity. We discerned a total of 21,535 expressed genes and identified 4,192 differentially expressed genes (DEGs) by RNA sequencing (RNA-seq). Our analysis revealed that 1,764 DEGs unique to G1 underwent thorough annotation and functional categorization utilizing diverse databases. Under drought conditions, the DEGs in G1 were predominantly linked to starch and sucrose metabolic pathways, plant hormone signaling, and glutathione metabolism. Notably, the drought-responsive genes in G1 were heavily implicated in hormonal modulation, such as ABA receptor3-like gene (PYL9), regulation by transcription factors (KAN4, BHLH80, ERF1B), and orchestration of drought-responsive gene expression. These results suggest that cultivar G1 possesses stronger stress tolerance and can better adapt to drought growing conditions. The congruence between qRT-PCR validation and RNA-seq data for 15 DEGs further substantiated our findings. Our research provides novel insights into the physiological adaptations of C. pilosula to arid conditions and lays the groundwork for the development of new, drought-tolerant C. pilosula cultivars.

Ethylene and epoxyethane metabolism in methanotrophic bacteria: comparative genomics and physiological studies using Methylohalobius crimeensis.

The genome of the methanotrophic bacterium Methylohalobius crimeensis strain 10Ki contains a gene cluster that encodes a putative coenzyme-M (CoM)-dependent pathway for oxidation of epoxyethane, based on homology to genes in bacteria that grow on ethylene and propylene as sole substrates. An alkene monooxygenase was not detected in the M. crimeensis genome, so epoxyethane is likely produced from co-oxidation of ethylene by the methane monooxygenase enzyme. Similar gene clusters were detected in about 10% of available genomes from aerobic methanotrophic bacteria, primarily strains grown from rice paddies and other wetlands. The sparse occurrence of the gene cluster across distant phylogenetic groups suggests that multiple lateral gene transfer events have occurred in methanotrophs. In support of this, the gene cluster in M. crimeensis was detected within a large genomic island predicted using multiple methods. Growth studies, reverse transcription-quantitative PCR (RT-qPCR) and proteomics were performed to examine the expression of these genes in M. crimeensis. Growth and methane oxidation activity were completely inhibited by the addition of >0.5% (v/v) ethylene to the headspace of cultures, but at 0.125% and below, the inhibition was only partial, and ethylene was gradually oxidized. The etnE gene encoding epoxyalkane:CoM transferase was strongly upregulated in ethylene-exposed cells based on RT-qPCR. Proteomics analysis confirmed that EtnE and nine other proteins encoded in the same gene cluster became much more predominant after cells were exposed to ethylene. The results suggest that ethylene is strongly inhibitory to M. crimeensis, but the bacterium responds to ethylene exposure by expressing an epoxide oxidation system similar to that used by bacteria that grow on alkenes. In the obligate methanotroph M. crimeensis, this system does not facilitate growth on ethylene but likely alleviates toxicity of epoxyethane formed through ethylene co-oxidation by particulate methane monooxygenase. The presence of predicted epoxide detoxification systems in several other wetland methanotrophs suggests that co-oxidation of ambient ethylene presents a stress for methanotrophic bacteria in these environments and that epoxyethane removal has adaptive value.

Genetic Adaptations of Soybean to Cold Stress Reveal Key Insights Through Transcriptomic Analysis

Low temperatures greatly restrict the development, growth, and productivity of soybeans, with their effects differing across various cultivars. The present work investigated the transcriptome and physiological reactions of two soybean cultivars, namely “KD52” exhibiting cold tolerance and “DS17” displaying cold sensitivity, to cold stress across a precisely defined period. The soybean plants were subjected to cold treatment at 6 °C for durations of 0, 2, 4, and 8 h. A comparative physiological marker study revealed distinct reactions to cold stress in the two cultivars. The findings showed that increased malondialdehyde levels provided evidence of DS17’s heightened vulnerability to lipid peroxidation and membrane degradation. In contrast, the KD52 cultivar exhibited increased activities of antioxidant enzymes, including peroxidase and superoxide dismutase, in response to cold exposure, suggesting a strong antioxidant defense system against oxidative stress. The transcriptomic analysis revealed dynamic responses, mapping 54,532 genes. Within this group, a total of 234 differentially expressed genes (DEGs) were found to be consistently changed at several time intervals, showing unique expression patterns across the two cultivars. Analysis of the association between these important DEGs and the physiological indicators revealed candidate genes that may be involved in controlling oxidative damage and antioxidant defenses. Some key genes showed a progressive rise in expression over time in both cultivars, with a more significant acceleration in KD52, and are probably involved in promoting adaptation processes during extended periods of cold exposure. The identification of improved defense mechanisms in KD52, together with the identification of crucial genes, offers great prospects for enhancing the cold stress resilience of soybean.

The role of NAADP in maintaining spontaneous heart contractions: comparative physiological studies

The goal of the work was to study the role of the second messenger NAADP (Nicotinic Acid Adenine Dinucleotide Phosphate), which causes the release of Ca2+ ions from lysosomes and endosomes, in the regulation of heart contractions. Isolated hearts of the grape snail Helix pomatia and a chicken embryo were used as models. Using the membrane-permeable acetooxymethyl ester NAADP-AM, we showed that NAADP at nanomolar concentrations increases the frequency and amplitude of spontaneous cardiac contractions in H. pomatia. The NAADP antagonist NED19, without affecting the amplitude of contractions, dose-dependently reduces their frequency, completely blocking spontaneous contractions of the mollusk heart at a concentration of 5 μM. The V-type H+-ATPase inhibitor bafilomycin A1 suppresses the accumulation of calcium ions in lysosomes and acidic endosomes. We have shown that bafilomycin A1 causes attenuation of spontaneous contractions and cardiac arrest in H. pomatia. Serotonin increases the amplitude of contractions of the H. pomatia heart without affecting heart rate. NED19 at saturating concentrations (10 μM) reduces the frequency of contractions when the snail heart is activated by serotonin, but only partially reduces their amplitude. In experiments with the isolated chick embryo heart, we showed that NED19 reduces the frequency of spontaneous contractions without affecting the amplitude of contractions. Based on the data obtained, a hypothesis was put forward that the release of calcium ions from lysosomes and endosomes under the influence of endogenous NAADP ensures the maintenance of spontaneous contractions of the heart.

Mobilome impacts on physiology in the widely used non-toxic mutant Microcystis aeruginosa PCC 7806 ΔmcyB and toxic wildtype

The Microcystis mobilome is a well-known but understudied component of this bloom-forming cyanobacterium. Through genomic and transcriptomic comparisons, we found five families of transposases that altered the expression of genes in the well-studied toxigenic type-strain, Microcystis aeruginosa PCC 7086, and a non-toxigenic genetic mutant, Microcystis aeruginosa PCC 7806 ΔmcyB. Since its creation in 1997, the ΔmcyB strain has been used in comparative physiology studies against the wildtype strain by research labs throughout the world. Some differences in gene expression between what were thought to be otherwise genetically identical strains have appeared due to insertion events in both intra- and intergenic regions. In our ΔmcyB isolate, a sulfate transporter gene cluster (sbp-cysTWA) showed differential expression from the wildtype, which may have been caused by the insertion of a miniature inverted repeat transposable element (MITE) in the sulfate-binding protein gene (sbp). Differences in growth in sulfate-limited media also were also observed between the two isolates. This paper highlights how Microcystis strains continue to “evolve” in lab conditions and illustrates the importance of insertion sequences / transposable elements in shaping genomic and physiological differences between Microcystis strains thought otherwise identical. This study forces the necessity of knowing the complete genetic background of isolates in comparative physiological experiments, to facilitate the correct conclusions (and caveats) from experiments.

Assessing the Susceptibility and Tolerance of Oil Palm Cultivars to Leaf-Bending: A Comparative Physiological and Nutritional Balance Study

Selecting the best oil palm cultivars adapted to specific agro-climatic conditions helps ensure fruit and oil production success. Many biotic and abiotic problems can limit the productivity of the crop, some of which have not yet been described, as well as their symptoms and degree of impact. In oil palm, a disturbance known as leaf-bending occurs, in which the palms present a bending or breakage of the petiole in the leaves, representing a significant challenge for oil palm cultivation. Although leaf-bending in oil palm plantations is known, its effect on the palm’s performance and its possible causes are unknown. Thus, the objectives of the present work were to describe and propose a quantitative way to evaluate leaf-bending in different cultivars (Elaeis guineensis Jacq. and the interspecific O×G hybrid) and to evaluate the disturbance effect on the physiology and nutritional balance of the oil palm. The results showed that most leaves from leaf rings three and four of the palm phyllotaxis have the highest affectation, with 74% leaf-bending. The cultivars with a Deli × La Mé and Coarí × La Mé genetic background were the most tolerant; however, the Deli × AVROS and Deli × Yangambi genetic crosses were the most susceptible. The difference in the affectation between the groups was 60% to 70%. Leaf-bending affected physiological parameters such as photosynthesis, transpiration, and stomatal conductance. Thus, below the second ring of leaves, the affected plants’ physiological parameters decreased between 40% and 50%. The nutritional diagnosis showed that the most sensitive cultivars to leaf-bending were Deli × AVROS, which presented the highest average index of nutritional balance (IBNm), indicating that this genetic cross had the highest nutritional imbalance. On the contrary, the most tolerant cultivars were Deli × La Mé, which presented the lowest IBNm, associated with a better nutritional condition.

Salicylic Acid's impact on Sedum alfredii growth and cadmium tolerance: Comparative physiological, transcriptomic, and metabolomic study

With the acceleration of industrialization, Cd pollution has emerged as a major threat to soil ecosystem health and food safety. Hyperaccumulating plants like Sedum alfredii Hance are considered to be used as part of an effective strategy for the ecological remediation of Cd polluted soils. This study delved deeply into the physiological, transcriptomic, and metabolomic responses of S. alfredii under cadmium (Cd) stress when treated with exogenous salicylic acid (SA). We found that SA notably enhanced the growth of S. alfredii and thereby increased absorption and accumulation of Cd, effectively alleviating the oxidative stress caused by Cd through upregulation of the antioxidant system. Transcriptomic and metabolomic data further unveiled the influence of SA on photosynthesis, antioxidant defensive mechanisms, and metal absorption enrichment pathways. Notably, the interactions between SA and other plant hormones, especially IAA and JA, played a central role in these processes. These findings offer us a comprehensive perspective on understanding how to enhance the growth and heavy metal absorption capabilities of hyperaccumulator plants by regulating plant hormones, providing invaluable strategies for future environmental remediation efforts.

Comparative Physiological Study of Pancreas in Eurasian Collared Dove (Streptopelia Decaocto) and Buzzard (Beuteo Beuteo Vulpinus)

Comparative Physiological Study of Pancreas in Eurasian Collared Dove (Streptopelia Decaocto) and Buzzard (Beuteo Beuteo Vulpinus)

A proteome perspective on adaptive responses to physiological challenges in marine mammals

While most mammals decrease energy expenditure while fasting, marine mammals such as northern elephant seals fast for several months while undergoing energy-intensive life history stages (e.g., postnatal development, molting, reproduction). Energy for these functions is provided by mobilization of large energy stores in blubber, which is driven by elevation of stress hormone levels across the fast. We used a proteome approach to examine potential mechanisms regulating fasting metabolism and responses to experimental stress challenges in elephant seals. We compared five proteome datasets and identified proteins that were altered by both fasting and experimental stress challenges across multiple life history stages and tissues in seals. These included lipid and hormone transport proteins (e.g., apolipoproteins, corticosteroid-binding globulin, transthyretin), acute phase proteins (e.g., alpha-2-macroglobulin, haptoglobin), antioxidant enzymes (e.g., glutathione peroxidase 3, catalase), adipokines (e.g., mimecan), and metabolic enzymes (e.g., fatty acid synthase, long chain fatty acid CoA ligase), among others. We suggest that these proteins may function as part of a core adaptive responses to physiological challenges in marine mammals. However, our ability to identify components of these responses has been hindered by several practical and technical challenges, and we will discuss the limitations and considerations for using a proteome approach in comparative physiology studies based on our experience. This research was funded by University of the Pacific and Offce of Naval Research. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Erythroid anion transport, nitric oxide, and blood pressure.

Glycophorin A and glycophorin B are structural membrane glycoproteins bound in the band 3 multiprotein complexes on human red blood cells (RBCs). Band 3 is an erythroid-specific anion exchanger (AE1). AE1-mediated HCO3 - transport provides the substrate for the enzyme-catalyzed conversion HCO3 - (aq) ⇌ CO2(g), which takes place inside the RBCs. Bicarbonate transport via AE1 supports intravascular acid-base homeostasis and respiratory excretion of CO2. In the past decade, we conducted several comparative physiology studies on Taiwanese people having the glycophorin variant GPMur RBC type (which accompanies greater AE1 expression). We found that increased anion transport across the erythrocyte membrane not only enhances gas exchange and lung functions but also elevates blood pressure (BP) and reduces nitric oxide (NO)-dependent vasodilation and exhaled NO fraction (FeNO) in healthy individuals with GP.Mur. Notably, in people carrying the GPMur blood type, the BP and NO-dependent, flow-mediated vasodilation (FMD) are both more strongly correlated with individual hemoglobin (Hb) levels. As blood NO and nitrite (NO2 -) are predominantly scavenged by intraerythrocytic Hb, and NO2 - primarily enters RBCs via AE1, could a more monoanion-permeable RBC membrane (i.e., GPMur/increased AE1) enhance NO2 -/NO3 - permeability and Hb scavenging of NO2 - and NO to affect blood pressure? In this perspective, a working model is proposed for the potential role of AE1 in intravascular NO availability, blood pressure, and clinical relevance.

A comparative physiological study of three red varieties in the Demarcated Douro Region

In certain regions, especially those with a Mediterranean climate, that are highly susceptible to climate change, viticulture is expected to become less suitable for the production of high-quality wines. From an evolutionary perspective, grapevine varieties have evolved genetic adaptations in the form of protective mechanisms to withstand summer stress, reflecting the climatic conditions in which grapevines were initially domesticated. The in-depth knowledge of the structural and functional characteristics of grapevines can aid in the identification and selection of varieties that are better suited to adverse environmental conditions and to the increasingly challenging conditions imposed by climate change. Following, this study aims to evaluate the extent to which the water status adjustment and the leaf biophysical and biochemical processes influence the respective photosynthetic performance of a currently neglected grapevine variety, Tinto Cão (TC) and two commonly used varieties in the Douro region, Touriga-Nacional (TN) and Tinta-Roriz (TR). The experiment was undertaken in the Baixo-Corgo sub-region of the Demarcated Douro Region in the north of Portugal. Grapevine water status, chlorophyll contents, leaf reflectance indices, chlorophyll a fluorescence (modulated and transient) and leaf gas exchange (including A/PPFD and A/Ci curves) were evaluated in three different phenological stages. The results indicate that, compared to TN and TR varieties, the TC minimizes the light-harvesting system while promoting thermal energy dissipation, which can be interpreted as photoprotective mechanisms at the photosynthetic apparatus level. These mechanisms imply the downregulation of the photochemical reactions but without significant losses of net productivity compared to TN, while TR remained increased. Despite the minor expression of Tinto-Cão nowadays, this variety can also have great adaptability for very hot and sunny wine-growing regions.

Effect of contaminated water on seed germination traits of crops

Lead (Pb) is one of the noxious trace metal element (TME) contaminants in the environment. In this work, we conducted a comparative physiological response study through some germination parameters between four cereals (Triticum durum, Triticum aestivum, Hordeum vulgare, and Zea mays) grown on a nutrient solution for 10 days and treated with three increasing levels of lead acetate (0.15, 0.3, and 0.6 g/L) in order to evaluate the impact of different lead concentrations on the germination capacity of these species. The results showed that lead has an abiotic stress effect on the four varieties examined at 0.3 g/L and 0.6 g/L. We recorded a significant to very highly significant effect in all the parameters studied. In the underground parts, in particular, a highly significant reduction in precocity of germination was recorded in Triticum durum, Triticum aestivum, Hordeum vulgare, and Zea mays. There was also a highly significant to very highly significant decrease in germination percentage in durum wheat, soft wheat, and maize. Under the most severe stress conditions (0.6 g/L), the barley variety showed stress tolerance with a germination rate of 92%. According to the findings of this study, the varieties examined can be grouped into two categories: variants that are susceptible to metal stress (Triticum durum, Triticum aestivum, and Zea mays) and varieties that are tolerant to lead exposure (Hordeum vulgare).

Comparative physiological study of sea cucumbers from eastern waters of United States.

Sea cucumbers, belonging to the phylum Echinodermata, are known to possess valuable bioactive compounds that have medicinal properties. In several countries, such as Korea, China, and Japan, they are cultured in the aquaculture industries for food and medicinal purposes. Research has shown that different species of sea cucumbers each possesses unique medicinal values. As a result, we strive towards finding species with better health resilience in aquaculture system to be cultured for nutritional and medicinal purposes. In this paper, we compared the physiological and immunological parameters of three species of sea cucumbers, Cucumaria frondosa (C. frondosa), Isostychopus badionotus (I. badionotus), and Pentacta pygmaea (P. Pygmaea) from the waters of the eastern United States as they have not been studied extensively. Four different cells of sea cucumbers, phagocytic, red spherule, white spherule, and vibratile cells, that contribute to their immunity were counted. C. frondosa exhibited the highest concentrations of phagocytic cells, white spherule cells, and vibratile cells, compared to the two other species. Due to its high phagocytic cell concentration, the highest phagocytic capacity was seen in C. frondosa although it was not statistically significant. We also observed that C. frondosa had the highest total cell count and the highest concentration of coelomic protein among the three species. Lastly, C. frondosa possessed the highest lysozyme activity. Taken together, we concluded that C. frondosa is the best of the three species compared to be reared in the aquaculture systems for use in the food and biomedicine industries due to its immunological and physiological properties.

Comparison of acoustic particle acceleration detection capabilities in three species of sharks.

Behavioural studies have shown that sharks are capable of directional orientation to sound. However, only one previous experiment addressed the physiological mechanisms of directional hearing in sharks. In this study we used a directional shaker table in combination with the auditory evoked potential (AEP) technique to understand the broadscale directional hearing capabilities in the New Zealand carpet shark Cephaloscyllium isabellum, rig shark Mustelus lenticulatus, and school shark Galeorhinus galeus. The aim of this experiment was to test if sharks are more sensitive to vertical (z-axis) or head-to-tail (x-axis) accelerations, and whether there are any differences between species. Our results support previous findings, suggesting that shark ears can receive sounds from all directions. Acceleration detection bandwidth was narrowest for the carpet shark (40-200Hz), and broader for rig and school sharks (40-800Hz). Greatest sensitivity bands were 40-80Hz for the carpet shark, 100-200Hz for the rig, and 80-100Hz for the school shark. Further, our results indicate that there may be differences in directional hearing abilities among sharks. The bottom-dwelling carpet shark is equally sensitive to vertical and head-to-tail particle accelerations. In contrast, both benthopelagic rig and school sharks appeared to be more sensitive to vertical accelerations at frequencies up to 200 Hz. This is the first study to provide physiological evidence that sharks may differ in their directional hearing and sound localisation abilities. Further comparative physiological and behavioural studies in more species with different lifestyles, habitats, and feeding-strategies are needed to further explore the drivers for increased sensitivity to vertical accelerations among elasmobranchs.

Effects of passages through an insect or a plant on virulence and physiological properties of the fungus Metarhizium robertsii.

Species of the genus Metarhizium are characterized by a multitrophic lifestyle of being arthropod parasites, rhizosphere colonizers, endophytes, and saprophytes. The process of adaptation to various organisms and substrates may lead to specific physiological alterations that can be elucidated by passaging through different hosts. Changes in virulence and cultivation properties of entomopathogenic fungi subcultured on different media or passaged through a live insect host are well known. Nevertheless, comparative in-depth physiological studies on fungi after passaging through insect or plant organisms are scarce. Here, virulence, plant colonization, hydrolytic enzymatic activities, toxin production, and antimicrobial action were compared between stable (nondegenerative) parent strain Metarhizium robertsii MB-1 and its reisolates obtained after eight passages through Galleria mellonella larvae or Solanum lycopersicum or after subculturing on the Sabouraud medium. The passaging through the insect caused similar physiological alterations relative to the plant-based passaging: elevation of destruxin A, B, and E production, a decrease in protease and lipase activities, and lowering of virulence toward G. mellonella and Leptinotarsa decemlineata as compared to the parent strain. The reisolates passaged through the insect or plant showed a slight trend toward increased tomato colonization and enhanced antagonistic action on tomato-associated bacterium Bacillus pumilus as compared to the parental strain. Meanwhile, the subculturing of MB-1 on the Sabouraud medium showed stability of the studied parameters, with minimal alterations relative to the parental strain. We propose that the fungal virulence factors are reprioritized during adaptation of M. robertsii to insects, plants, and media.

Urea transport in human red blood cells: Donor variation compared to chloride, glucose, and water transport.

We determined the permeability (P, cm/s) of unmodified human red blood cells (HRBC) to urea (Pu), chloride (PCl), glucose (Pglu), and water diffusion (Pd) under conditions of self-exchange (SE) with the continuous flow tube method at pH 7.2, 25°C. Among 24 donors, Pu at 1 mM varied >100%. Two of the donors were also tested in 1983. Their Pu had decreased by 77 and 90%. High age in males and Kidd genotype Jk(a+,b+), but not blood types AB0, appear related to low Pu. For one of the two donors, PCl (150 mM, 38°C, pH 7.2), Pglu (1 mM, 38°C, pH 7.2), and Pd (55.5 M, 25°C, pH 7.2) were determined then and now and showed no significant changes with age. The results from six more donors show donor PCl, Pglu, and Pd in the range of ≈1%. PCl and Pglu are vital for the metabolism of cells and tissues, and we see but little donor variation, and so far, no phenotypes without glucose (GLUT1) and anion (AE1) transporters in HRBC. Phenotypes with no urea transporter (UT-B) or no water transporters (aquaporin, AQP1) are registered and are compatible with life. Our results are in line with the concept that the solutes do not share pathways in common. The great donor variation in Pu must be considered in comparative transport physiological studies.

Comparative physiological, antioxidant and proteomic investigation reveal robust response to cold stress in Digitalis purpurea L.

Digitalis purpurea (L) is an important medicinal plant growing at Alpine region of Himalayas and withstands low temperatures and harsh climatic conditions existing at high altitude. It serves as an ideal plant system to decipher the tolerance to cold stress (CS) in plants from high altitudes. To understand the complexity of plant response to CS, we performed a comparative physiological and biochemical study complemented with proteomics in one-month-old D. purpurea grown at 25°C (control) and 4°C (CS). We observed an enhanced accumulation of different osmo-protectants (glycine betaine, soluble sugar and proline) and higher transcription (mRNA levels) of various antioxidant enzymes with an increased antioxidant enzyme activity in D. purpurea when exposed to CS. Furthermore, higher concentrations of non-enzymatic antioxidants (flavonoids, phenolics) was also associated with the response to CS. Differential proteomic analysis revealed the role of various proteins primarily involved in redox reactions, protein stabilization, quinone and sterol metabolism involved in CS response in D. purpurea.. Our results provide a framework for better understanding the physiological and molecular mechanism of CS response in D. purpurea at high altitudes.

Hypoxic response patterns in lung tissue: An integrated analysis of comparative physiological and transcriptomic studies from Neodon fuscus and Lasiopodomys brandtii

Oxygen (O2) is essential for the survival and reproduction of most species. However, in recent years, with global climate change and the increasing impact of human activities on the ecosystem, the frequency of extreme environmental events, such as heat waves, cold waves, droughts, and floods, has increased, resulting in dramatic changes in environmental oxygen concentration (hypoxic environment, etc.), threatening the survival of animals and pushing them toward extreme adaptation. In this context, how organisms, especially those with differences in original habitats, adapt to low oxygen environment is particularly important. In this study, we systematically analyzed hypoxic response patterns in lung tissues of small rodents Neodon fuscus, Lasiopodomys brandtii, and Mus musculus with different experiences of natural hypoxia tolerance through laboratory simulation of hypoxia environment, combined with hematological, histological, and transcriptomic analysis. Our results show that all three species exhibit increased antioxidant defense and damage repair ability to a certain extent under hypoxia, although the specific molecular mechanisms are not the same. L. brandtii showed better damage repair ability than the others, which is likely to be closely related to the intermittent hypoxia environment experienced in the natural environment, and genes such as Glrx5, Prdx2, Col1a1, Lama1, and Eln may play a crucial role in this process. In addition, we found that both N. fuscus and L. brandtii appropriately enhanced oxygen transport in tissues under hypoxic conditions, with a series of functional genes related to hemoglobin synthesis and vascular smooth muscle contraction were significantly up-regulated in both species of voles, such as Actg2, Ptgir, Alas2, Hba, Hbb and Bpgm. Our results, to a certain extent, reveal the differences and similarities of hypoxic response patterns in lung tissues of small rodents with different hypoxic life histories and provide a relatively perfect analytical paradigm for related studies.

Light, rather than circadian rhythm, regulates gas exchange in ferns and lycophytes.

Circadian regulation plays a vital role in optimizing plant responses to the environment. However, while circadian regulation has been extensively studied in angiosperms, very little is known for lycophytes and ferns, leaving a gap in our understanding of the evolution of circadian rhythms across the plant kingdom. Here, we investigated circadian regulation in gas exchange through stomatal conductance and photosynthetic efficiency in a phylogenetically broad panel of 21 species of lycophytes and ferns over a 46 h period under constant light and a selected few under more natural conditions with day-night cycles. No rhythm was detected under constant light for either lycophytes or ferns, except for two semi-aquatic species of the family Marsileaceae (Marsilea azorica and Regnellidium diphyllum), which showed rhythms in stomatal conductance. Furthermore, these results indicated the presence of a light-driven stomatal control for ferns and lycophytes, with a possible passive fine-tuning through leaf water status adjustments. These findings support previous evidence for the fundamentally different regulation of gas exchange in lycophytes and ferns compared to angiosperms, and they suggest the presence of alternative stomatal regulations in Marsileaceae, an aquatic family already well known for numerous other distinctive physiological traits. Overall, our study provides evidence for heterogeneous circadian regulation across plant lineages, highlighting the importance of broad taxonomic scope in comparative plant physiology studies.

New Method for Rapid 3D Reconstruction of Semi-Transparent Underwater Animals and Structures.

Morphological features are the primary identifying properties of most animals and key to many comparative physiological studies, yet current techniques for preservation and documentation of soft-bodied marine animals are limited in terms of quality and accessibility. Digital records can complement physical specimens, with a wide array of applications ranging from species description to kinematics modeling, but options are lacking for creating models of soft-bodied semi-transparent underwater animals. We developed a lab-based technique that can live-scan semi-transparent, submerged animals, and objects within seconds. To demonstrate the method, we generated full three-dimensional reconstructions (3DRs) of an object of known dimensions for verification, as well as two live marine animals-a siphonophore and an amphipod-allowing detailed measurements on each. Techniques like these pave the way for faster data capture, integrative and comparative quantitative approaches, and more accessible collections of fragile and rare biological samples.