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The Indonesian shortfin eel (Anguilla bicolor bicolor McClelland, 1884) is catadromous fish. The developmental phase of the fish is influenced by the availability and type of feed, and dissolved oxygen levels (DO). Oxygen level fluctuations during migration from sea to fresh waters can cause hypoxia and trigger activation of the Hypoxia-inducible factor 1 alpha gene (HIF-1α). Therefore, undertanding HIF-1α expression is very important in understanding the life cycle and physiology of this organism. This study aimed to perform a histological comparison between the liver structure of eel in the elver eel phase to silver eel and compared the expression of HIF-1α in the liver. The eels were collected from Kulon Progo Regency, Segara Anakan in Cilacap, and Cangkringan in Sleman, respectively. The eel livers were prepared with standard paraffin method. The samples were stained with Hematoxylin-Eosin, Mallory Acid Fuchsin and Periodic Acid-Schiff Alcian Blue for histological observation. The HIF-1α protein expression was detected using immunohistochemistry. The results showed that the structure of liver elver, yellow, and silver eel shared similar tubular hepatocytes. Moreover, there was no significant differences in the parenchymal structure of liver of all stage of eel. Mucin levels were different in each life cycle phase. HIF-1α expression varied by eel phase, with the elver eel showing weak expression, yellow stage showing moderate expression, and silver eels displaying the highest levels of expression. We conclude that the highest expression of HIF-1α was found in the silver eel, which resides in freshwater environments and is found in freshwater while returning to the sea for reproduction. [ABSTRACT FROM AUTHOR]

Today, the general situation worldwide is that the hospitals, sanatoriums and medical colleges are running out of beds, oxygen, medical staff, ventilators and other required paraphernalia that is mandatory for the treatment of the vicious pandemic [1]. The requirement is for a system that takes in some input parameters like Oxygen level of the patient, pulse rate and respiration rate and in turn predicts the Life Risk Rate of that patient [2]. The model used here is a fuzzy regression model that gives the prediction of Life Risk Rate between 1 and 10 units. The lower the predicted Life Risk Rate, the better the chances of survival of the Covid patient. But if the predicted Life Risk Rate is more than the mean of the observations of the Risk in the dataset, then immediate emergency is needed. The benefit of this system is that the patients requiring immediate admission and treatment can be filtered and medical aid in hospital be thereby provided for critical patients. Rest may be home quarantined and domestic medical aid may be given to them until in some unfortunate situation their Risk Rate is near alarming. This paper aims to provide some help in this crucial situation. [ABSTRACT FROM AUTHOR]

Abstract: The mechanisms underlying headaches attributed to hypoxia are poorly known. The activation of spinal trigeminal neurons with meningeal afferent input is believed to be responsible for the generation of headaches. In the caudal spinal trigeminal nucleus of anaesthetized and ventilated rats, the spontaneous firing of neurons with input from the exposed parietal dura mater and the activity evoked by mechanical stimuli to the dura and the adjacent periosteum were recorded, whereas the O2 fraction of the ventilation gas was stepwise reduced by omitting O2 and adding nitrogen. The expiratory CO2 level, the arterial pressure, the pulse rate, and the peripheral O2 saturation (SpO2) were registered. The meningeal blood flow was recorded using laser Doppler flowmetry; video imaging was used to measure the diameter of dural and medullary arteries. Lowering O2 in the ventilation gas from hyperoxic to normoxic and finally hypoxic conditions was followed by an increase in spontaneous activity up to 300% of the initial activity in most neurons, whereas the activity in a minor fraction of neurons ceased. The mechanical threshold was reduced under hypoxia. Arterial pressure, pulse rate, and SpO2 fell during stepwise lowering of the O2 concentration, whereas the arteries of the dura mater and the medulla dilated. Increased neuronal activity in the spinal trigeminal nucleus following lowering of the inhaled O2 goes along with variations in cardiovascular parameters. The experiments may partly model the conditions of high altitudes and other hypoxic states as risk factors for headache generation. [ABSTRACT FROM AUTHOR]

Colorectal cancer is a common cancer with metachronous distant metastases still threatening overall survival. Tumor oxygen level influences tumor radiosensitivity in relation to autophagy and apoptosis. The objective of this study is to evaluate the expression and interaction between multiple key regulators in different oxygen levels. Human colorectal adenocarcinoma HT-29 cells were cultured in 1% or 10% oxygen level and irradiated by 2 Gy with different incubation time. Autophagy key regulators, AMPK, HIFs and JNK were evaluated by Western blot. Sequential autophagy key regulator activation was observed in the order of AMPK, HIF-1α, HIF-2α and JNK. 10% oxygen level could promote autophagy with similar degree of autophagy activation as 1% oxygen level in 48-h while irradiation could slightly inhibit autophagy. The results of this study supported prior evaluation of oxygen level and autophagy regulators for improving treatment efficacy and indicated the possible directions in developing individualized radiotherapy by selective targeting of hypoxic regions. • 10% O 2 level can promote autophagy with similar degree as 1% O 2 level in 48-h. • Sequential autophagy activation in the order of AMPK, HIF-1α, HIF-2α and JNK. • JNK for delayed autophagy activation as a novel key finding in low oxygen levels. [ABSTRACT FROM AUTHOR]

Mesenchymal stromal cells (MSCs) are a population of adult stem cells that modulate functional state of neighboring tissues. During cell aging, the biological activity of MSC changes, which may affect tissue homeostasis. It is known that reducing the oxygen level in vitro to physiological values typical to a particular cell niche leads to attenuation of some morphological and functional changes associated with aging. This work aimed to study gene expression in MSCs involved in response to physiological hypoxia using a replicative aging model under physiological (5%) and atmospheric (20%) oxygen in cultures. Our results show that significant reduction of proliferative activity of MSCs is observed after 20 passages (~50 cell generations). Regardless of the oxygen, in senescent cells PKM2, SERPINE1, and VEGFA were upregulated while ANKRD37, DDIT4, HIF1A, and TXNIP were downregulated. Also, ADORA2B, BNIPL, CCNG2, EGLN1, MAP3K1, MXI1, and P4HA1 were downregulated under hypoxia. The effect of oxygen was more pronounced at earlier passages both on the cellular and transcription levels. Irrespective of the passage, genes ANGPTL4, GYS1, PKM2, SERPINE1, and TP53 were downregulated under hypoxia. Also, decreased expression was observed for ADM, F10, HMOX1, P4HB, PFKL, SLC16A3 in earlier passages, and for HK2 – in later passages. Upregulation was only observed for ANKRD37, both at early and late cultures. [ABSTRACT FROM AUTHOR]

Methanotrophy of arable soils is affected by N fertilization, but the knowledge about the effect of oxygen level is poorly understood; soil aeration can fluctuate and zones of low oxygen are widespread in soil. We monitored CH4 oxidation in three mineral soils (Eutric Cambisol, Haplic Podzol, Mollic Gleysol) under laboratory conditions by varying the O2 level (from 20 to 2% O2), with or without NH4+ (100 mg N kg−1). In controls (without NH4+), CH4 was oxidized completely in the O2 range from oxia (20% O2) to high hypoxia (5% O2), while the process was inhibited under microoxia (2% O2). Ammonium application decreased CH4 consumption in all soils. This negative effect was stronger at 20% and 2% O2 than under hypoxia. The highest CH4 oxidation rates and the shortest initial (lag) phases in both control and NH4+-amended soils were observed under high (5% O2) and low (10% O2) hypoxia. [ABSTRACT FROM AUTHOR]

Our understanding of the effects of temperature on granulosa cell (GC) physiology is primarily limited to in vitro studies conducted under atmospheric (∼20% O 2 ) conditions. In the current series of factorial experiments we identify important effects of O 2 level (i.e. 5% vs 20% O 2 ) on GC viability and steroidogenesis, and go onto report effects of standard (37.5 °C) vs high (40.0 °C) temperatures under more physiologically representative (i.e. 5%) O 2 levels in the presence of different levels of melatonin (0, 20, 200 and 2000 pg/ml); a potent free-radical scavenger and abundant molecule within the ovarian follicle. Cells aspirated from antral (4–6 mm) follicles were cultured in fibronectin-coated wells using serum-free M199 for up to 144 h. At 37.5 °C viable cell number was enhanced and luteinization reduced under 5 vs 20% O 2 . Oxygen level interacted (P < 0.001) with time in culture to affect aromatase activity and cell estradiol (E 2 ) production (pg/mL/10 5 cells). These decreased between 48 and 96 h for both O 2 levels but increased again by 144 h for cells cultured under 5% but not 20% O 2 . Progesterone (P 4 ) concentration (ng/mL/10 5 cells) was greater (P < 0.001) under 20 vs 5% O 2 at 96 and 144 h. Cell number increased (P < 0.01) with time in culture under 5% O 2 irrespective of temperature. However, higher doses of melatonin increased viable cell number at 40.0 °C but reduced viable cell number at 37.5 °C (P = 0.004). Melatonin also reduced (P < 0.001) ROS generation at both O 2 levels across all concentrations. E 2 increased with time in culture at both temperatures under 5% O 2 , however P 4 declined between 96 and 144 h at 40.0 but not 37.5 °C. Furthermore, melatonin interacted (P < 0.001) with temperature in a dose dependent manner to increase P 4 at 37.5 °C but to reduce P 4 at 40.0 °C. Transcript expression for HSD3B1 paralleled temporal changes in P 4 production, and those for HBA were greater at 5% than 20% O 2 , suggesting that hemoglobin synthesis is responsive to changes in O 2 level. In conclusion, 5% O 2 enhances GC proliferation and reduces luteinization. Elevated temperatures under 5% O 2 reduce GC proliferation and P 4 production. Melatonin reduces ROS generation irrespective of O 2 level and temperature, but interacts with temperature in a dose dependent manner to influence GC proliferation and luteinization. [ABSTRACT FROM AUTHOR]

In this study, comparative studies on Sn whisker growth in Sn-0.3Ag-0.7Cu-1Pr solder under different environments were conducted to investigate factors like ambient temperature, oxygen level, and 3.5 wt% NaCl solution on whisker growth. The experimental results revealed that ambient temperature and oxygen level are two important factors that could determine the oxidation rate of PrSn 3 phase, thus indirectly affecting the growth rate of Sn whiskers. In addition, mechanisms of whisker growth under these three environments were established from the perspective of atom diffusion based on the “compressive stress-induced” theory. Although whiskers under different environments were all squeezed out from Pr oxides (hydroxides), the forms of their driving forces were different. For whiskers squeezed out in air whether at room temperature or 150 °C, the driving force is the compressive stress produced by lattice expansion due to the oxidation of PrSn 3 phase. The representative example was whiskers' growth at 150 °C, which could be simplified as three stages: (1) squeezing out, (2) cracking and (3) bursting out. For whisker growth in 3.5 wt% NaCl solution, the driving force for much fewer whiskers' growth was proposed to come from lateral stress provided by interfacial IMC layer growth. Moreover, Sn nanoparticles and their agglomerations were also found to form under the driving force of the potential difference between Sn atoms and Sn crystals. Their morphologies could also be affected by factors of ambient temperature, oxygen level and Cl − ions in corrosive liquid. [ABSTRACT FROM AUTHOR]

Abstract The ability of soil to uptake methane is regulated by several factors affecting soil microbial activity. The soil oxygen concentration is usually lower than the concentration of atmospheric air, and nitrogen fertilization contributes to a significant increase in nitrate-N in soil. Therefore, we selected three agricultural soils (Eutric Cambisol, Haplic Podzol, Mollic Gleysol) to investigate interactive effects of oxygen and nitrate (KNO 3) on CH 4 oxidation including different gradients of O 2 (20%, 10%, 5%, 2%) and nitrate (0, 100, 200 mg N kg−1). The soils varied in their response to O 2 and nitrate treatments. In the absence of nitrate, all soils completely oxidized added CH 4 (1%) under the oxygen concentrations used (except 2%O 2); however, low oxygen (5%; 10%O 2) was optimal. Both nitrate doses strongly stimulated methane oxidation at 2%O 2 in Podzol and Gleysol, but generally inhibited CH 4 uptake in Cambisol. Highlights ⁃ Hypoxia (5%; 10%O 2) was optimal for CH 4 uptake in Podzol and Gleysol with NO 3 − ⁃ NO 3 − negatively affected CH 4 uptake in Cambisol at 20%, 10%, and 5%O 2 ⁃ Nitrate stimulated CH 4 uptake in three soils under 2%O 2 [ABSTRACT FROM AUTHOR]

The present study was undertaken to evaluate the individual and combined effects of oxygen concentration and diet composition on the growth, nutrient utilization and intestinal morphology of Nile tilapia ( Oreochromis niloticus ). Two recirculating aquaculture systems were used to create the difference in oxygen concentration: normoxia (6.9 mg·L − 1 ) and hypoxia (3.5 mg·L − 1 ). Two diets were formulated using a different soybean meal (SBM) content to create a contrast in the potential to affect the gut barrier function. Triplicate groups of 35 fish with initial mean body weight of 23 g were fed “Control” diet containing 20% fish meal and “Test” diet containing only plant protein source at normoxia and hypoxia for 8 weeks. Six fish per treatment were sampled for intestinal morphological analysis at the end of week 1, 4 and 8. The proximal, middle and distal intestine were processed for quantitative histology, in order to count goblet cells (GC) and eosinophilic granulocytes (EG); and to measure the thickness of lamina propria (LP) and sub-epithelial mucosa (SM). The study showed that growth was best in the “Control” diet under normoxia, while no interaction between oxygen and diet composition was found. Hypoxia reduced nutrient digestibility significantly ( p < 0.05). For the “Test” diet, the decline in digestibility was larger than for “Control” diet over time. Both diet composition and oxygen level induced changes in intestinal morphology of Nile tilapia. We observed a thickening of the LP and SM caused by an increased infiltration of inflammatory cells, and an increased number of GC and EG among the enterocytes. The negative effect of increased soybean meal on intestinal morphology was enhanced at low oxygen level and aggravated in time. The SBM enteritis-like symptoms were more pronounced in the proximal than in the distal intestine of Nile tilapia. Statement of relevance Too many nutritional papers focus only on the growth response of fish. Here we describe effects of diet composition and oxygen on growth, digestibility and intestinal health. Modern aquaculture can benefit from this holistic approach. [ABSTRACT FROM AUTHOR]

One of the most important events in vertebrate evolutionary history is the water-to-land transition, during which some morphological and physiological changes occurred in concert with the loss of specific genes in tetrapods. However, the molecular mechanisms underlying this transition have not been well explored. To explore vertebrate adaptation to different oxygen levels during the water-to-land transition, we performed comprehensive bioinformatics and experimental analysis aiming to investigate the NAMPT family in vertebrates. NAMPT, a rate-limiting enzyme in the salvage pathway of NAD+ biosynthesis, is critical for cell survival in a hypoxic environment, and a high level of NAMPT significantly augments oxidative stress in normoxic environments. Phylogenetic analysis showed that NAMPT duplicates arose from a second round whole-genome duplication event. NAMPTA existed in all classes of vertebrates, whereas NAMPTB was only found in fishes and not tetrapods. Asymmetric evolutionary rates and purifying selection were the main evolutionary forces involved. Although functional analysis identified several functionally divergent sites during NAMPT family evolution, in vitro experimental data demonstrated that NAMPTA and NAMPTB were functionally conserved for NAMPT enzymatic function in the NAD+ salvage pathway. In situ hybridization revealed broad NAMPTA and NAMPTB expression patterns, implying regulatory functions over a wide range of developmental processes. The morpholino-mediated knockdown data demonstrated that NAMPTA was more essential than NAMPTB for vertebrate embryo development. We propose that the retention of NAMPTB in water-breathing fishes and its loss in air-breathing tetrapods resulted from vertebrate adaptation to different oxygen levels during the water-to-land transition. [ABSTRACT FROM AUTHOR]

The aim of this paper was to study the influence of four process variables (turning frequency, gas-phase oxygen level, type of bulking agent and sludge/bulking agent mixing ratio) on the performance of the sewage sludge composting process using a rotary drum pilot scale reactor, in order to optimize the thermophilic stage and reduce the processing time. Powdered sawdust, wood shavings, wood chips, prunings waste and straw were used as bulking agents and the thermophilic stage temperature profile was used as the main indicator for gauging if the composting process was developing correctly. Our results showed that a 12 h−1 turning frequency and an oxygen concentration of 10% were the optimal conditions for the composting process to develop. The best results were obtained by mixing the sewage sludge with wood shavings in a 3:1 w/w ratio (on a wet basis), which adapted the initial moisture content and porosity to an optimal range and led to a maximum temperature of 70 °C being reached thus ensuring the complete removal of pathogens. Moisture, C:N ratio, pH, organic matter, heavy metals, pathogens and stability were all analysed for every mixture obtained at the end of the thermophilic stage. These parameters were compared with the limits established by the Spanish regulation on fertilizers (RD 824/2005) in order to assess if the compost obtained could be used on agricultural soils. The right combination of having optimal process variables combined with an appropriate reactor design allowed the thermophilic stage of the composting process to be speeded up, hence obtaining a compost product, after just two weeks of processing that (with the exception of the moisture content) complied with the Spanish legal requirements for fertilizers, without requiring a later maturation stage. [Copyright &y& Elsevier]

Few papers have been published in the open literature on the emissions from biomass fuels, including wood pellets, during the storage and transportation and their potential health impacts. The purpose of this study is to provide data on the concentrations, emission factors, and emission rate factors of CO2, CO, and CH4 from wood pellets stored with different headspace to container volume ratios with different initial oxygen levels, in order to develop methods to reduce the toxic off-gas emissions and accumulation in storage spaces. Metal containers (45 l, 305 mm diameter by 610 mm long) were used to study the effect of headspace and oxygen levels on the off-gas emissions from wood pellets. Concentrations of CO2, CO, and CH4 in the headspace were measured using a gas chromatograph as a function of storage time. The results showed that the ratio of the headspace ratios and initial oxygen levels in the storage space significantly affected the off-gas emissions from wood pellets stored in a sealed container. Higher peak emission factors and higher emission rates are associated with higher headspace ratios. Lower emissions of CO2 and CO were generated at room temperature under lower oxygen levels, whereas CH4 emission is insensitive to the oxygen level. Replacing oxygen with inert gases in the storage space is thus a potentially effective method to reduce the biomass degradation and toxic off-gas emissions. The proper ventilation of the storage space can also be used to maintain a high oxygen level and low concentrations of toxic off-gassing compounds in the storage space, which is especially useful during the loading and unloading operations to control the hazards associated with the storage and transportation of wood pellets. [ABSTRACT FROM PUBLISHER]

Air, which is the material that composes the atmosphere, is a mixture of invisible gases. The atmospheric air consists of approximately 78% nitrogen and 21% oxygen. The remainder is made up of argon, carbon dioxide, several other gases, and water vapor. The combustion of fossil fuels is the greatest source of atmospheric pollution. A convenient way to develop quantitative theory on the critical oxygen levels has been dependent on the diffusion process. The average diffusion rates (ADRs) depend on the diffusion process. The diffusion of fuel combustion gases might be affected from local atmospheric pressure, gas flow pattern, process, and height from the earth surface. The ADRs of the gases depend on height and the ADRs reach maximum values at 25 m height. [ABSTRACT FROM AUTHOR]

Abstract: In order to investigate the effect of lactose concentration and oxygen level on the growth and metabolism of Kluyveromyces marxianus UFV-3 in cheese whey permeate, batch cultures were conducted under aerobic, hypoxic, and anoxic conditions, with lactose at initial concentration ranging from 1 to 240gL−1. The increase in lactose concentration increased ethanol yield and ethanol volumetric productivity, and has reduced cell yield. When lactose concentration was equal or above 50gL−1 and the oxygen levels were low, the ethanol yield was close to its theoretical value. Maximum ethanol concentrations attained in this study were 76 and 80gL−1 in hipoxia and anoxia, respectively. The lactose consumption rate in anoxia was greater than in aerobiosis and hipoxia. However, under anoxia, the lactose consumption rate of K. marxianus followed a saturation kinetics, which was not observed in hypoxia and aerobiosis. All oxygen levels investigated, showed a tendency for saturation of the ethanol production rate above 65gL−1 lactose. Ethanol production rate was also higher on anoxia. [Copyright &y& Elsevier]

The bio-oxidation of 2,3-butanediol to acetoin and diacetyl was studied exploiting the membrane-bound alcohol dehydrogenase activity of whole cells of Acetobacter hansenii MIM 2000/5, which previously proved very effective in the dehydrogenation of primary and secondary alcohols as well as diols. The experimental data of concentrations of C-containing products (acetoin, diacetyl, biomass and carbon dioxide) and 2,3-butanediol, collected versus time during batch oxidations, were used to propose and check a mechanistic model for such a biosystem. Based on the present knowledge on the respiratory chain of acetic acid bacteria, material balances performed at different starting concentrations of the carbon source (1.8–10 g l−1) and oxygen levels (10.0–27.5% of the saturation value in water) were used in a bioenergetic study of 2,3-butanediol bio-oxidation. The experimental data at various oxygen levels allowed estimating the P/O ratio making different energetic hypotheses for the catabolism. The values of this parameter were particularly low (0.17–1.04 molATP molO−1) if compared with those reported for the growth of different aerobes on simple carbon sources, thus suggesting a dependence of the ATPase activity on the medium composition and the existence of an energy-expensive system for acetoin transfer into the cell. The estimated overall energy consumption for cell growth and maintenance proved to be a decreasing function of the starting carbon source concentration. [Copyright &y& Elsevier]

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that have been extensively used as tools for paleoclimate reconstruction. Temperature and pH were thought to be two major factors affecting the distributions of brGDGTs; however, the effects of other factors on the distribution of brGDGTs and related temperature and pH proxies in soil environments remain unclear. Here, we investigated iso- and br-GDGT distributions in three soil profiles (SPs) developed on bedrocks consisting of hornfels (HP), granite (GP), and basalt (BP), respectively. The downward environmental factors in these SPs differ, thus providing a chance to evaluate their effects on the distribution of brGDGTs. In the three SPs, the methylation degree for 5-methyl and total brGDGTs (MBT′ 5ME and MBT′), respectively, varied significantly downwards despite minor changes in soil temperature, highlighting a non-temperature effect. The depth-dependence of these proxies appears to be caused by the oxygen level. The MBT′ for 5- or 6-methyl brGDGTs (MBT′ 5ME and MBT′ 6ME), or total brGDGTs (MBT′), increased as the oxygen level decreased, suggesting tetramethylated brGDGTs (Ia, Ib, and Ic) would increase in abundance with decreased oxygen level. The two pH proxies, CBT and IR 6ME , both decreased at lower oxygen levels. Such regulation of brGDGT compositions in response to oxygen availability could be explained by the changing bacterial communities that have different oxygen preferences. The possible oxygen level impact on the distribution of GDGTs could result in brGDGT-inferred temperature skewed towards higher values and pH towards lower values with decreased oxygen level. This finding may also have implications for the mechanism of soil aridity impact on the brGDGT-based proxies in semi-arid and arid regions, which is of profound importance for paleotemperature and hydroclimate reconstruction in loess-paleosol sequences. Increasing soil aridity could lead to changes in brGDGT-based proxies similar to that observed at the higher oxygen level, i.e., lower MBT′, higher CBT, and higher IR 6ME. As soil aridity is generally associated with better aeration and higher oxygen level, we argue that changes in oxygen level might be the real cause of the bias in brGDGT-based proxies in soils from semi-arid and arid regions. • GDGTs in three soil profiles with varying environmental factors investigated. • Oxygen level could be a factor influencing the distribution of GDGTs in soil environments. • Lower oxygen levels led to higher MBT', lower CBT and IR 6ME. [ABSTRACT FROM AUTHOR]

Anadromous sub-populations of stenohaline freshwater fish are vastly understudied in the estuarine environment. The purpose of the present study was therefore to study the population ecology, growth rate, and physico-chemical environment of an anadromous sub-population of European perch (Perca fluviatilis) from the western Baltic Sea. Fish (301) were marked with external identification tags, and anglers and fishermen reported recaptures in a citizen science set-up over three years. In addition, scale samples were collected for population growth rate determination. Furthermore, water temperature, salinity, and oxygen concentration were monitored in the area. The fish showed a consistent annual migration pattern over the three years residing in a bay during summer while being in a delta during autumn, winter, and spring. The population had a high growth rate, but a meta-analysis showed that growth of European perch is not distinctly different between estuarine and freshwater populations. The average salinity measured in the area was around 10, but increased on multiple occasions to salinity levels known for being physiologically challenging for European perch. We argue that high growth rates of estuarine European perch is more likely due to high food availability and low interspecific competition in this environment, rather than due to physiologically optimal salinities. Furthermore, the European perch in the present study lived on the edge of the species salinity tolerance, and the migration into the delta during winter is likely a combination of avoiding high salinities at low temperatures and a spawning migration. These results are important knowledge for the management of estuaries and coastal areas, especially as climate change is locally altering these environments drastically, and calls for further studies on other anadromous sub-populations of stenohaline freshwater fish. • The fish resided in a bay during summer and overwintered in a delta. • Growth rate of European perch is not different in estuaries and freshwater habitats. • Anadromous European perch temporarily experience and survive salinities up to 22. • High salinity incidents co-occurred with hypoxic conditions. [ABSTRACT FROM AUTHOR]

Crustacean trace fossils provide invaluable information to paleobilogical, environmental and ecological interpretations in the Earth history. Here we report an unusually large (segments up to 58 mm across), three-dimensional burrow system from the Lower Devonian Pingyipu Formation, which was deposited in a nearshore setting on the northwestern Yangtze Platform, South China. The burrow system is dominated by horizontally-developed networks probably with vertical shafts connecting to the sediment-water interface. The burrow surfaces show no signs of lining but are characterized by scratches including ridges and bundles of ear-shaped striae, implying an assignation to Spongeliomorpha aff. S. chevronensis (Muñiz and Mayoral 2001). The overall morphological and taphonomic features suggest permanent, open burrows, produced in a substrate with considerable firmness. Further investigation indicates that the burrow system may have been constructed by a colony of large, unknown crustacean with thoracic appendages decorated with acute seta or denticulations. They generally served a combined purpose of dwelling and perhaps feeding on microbial growth accumulating on the tunnel margins. These burrows represent the earliest known three-dimensional burrow systems constructed by a crustacean that may be comparable to their modern analogues in both morphological and functional aspects. The unusually large size of the burrows may have been favored by a higher atmospheric oxygen level during the Early Devonian. • An unusually large burrow system from the Lower Devonian is illustrated. • It is the earliest known three-dimensional system constructed by crustaceans. • Morphological and functional features may be comparable to its modern analogues. • Occurrence of the burrows was favored by a higher atmospheric oxygen level. [ABSTRACT FROM AUTHOR]

(1) Background: Epithelial–mesenchymal transition (EMT) and cancer cell stemness maintenance (SM) are important factors for cancer metastasis. Although hypoxia has been considered as a possible factor for EMT induction and promotion of SM, studies in this area, apart from hypoxia-inducible factor (HIF) pathways and severe hypoxia, are scant. This study aimed to evaluate the effects of different oxygen levels on EMT induction and SM and elucidate the signaling pathways involved in colorectal cancer cells. (2) Methods: Cell morphological analysis, migration assay, immunofluorescence staining of cytoskeleton and Western blotting were performed on human colorectal cancer cells HT-29, DLD-1, and SW-480 cultured at 1%, 10%, and normal (21%) O2 levels. The role played by c-Jun N-terminal kinase (JNK) was evaluated through the use of the specific JNK inhibitor SP600125. (3) Results: This study evaluated 1% and 10% O2 are possible conditions for EMT induction and SM. This study also demonstrated the partial relieve of EMT induction and SM by SP600125, showing the importance of the JNK pathway in these processes. Furthermore, this study proposed a novel pathway on the regulation of Akt by JNK-c-Jun. (4) Conclusions: This study suggests 10% O2 as another possible condition for EMT induction, and SM and JNK pathways play important roles in these processes through multiple factors. Inhibition of JNK could be explored as treatment for inhibiting metastasis in colorectal cancer cells. [ABSTRACT FROM AUTHOR]