pCO2 Levels Research Articles

Lipidomics Identified Lyso-Phosphatidylcholine and Phosphatidylethanolamine as Potential Biomarkers for Diagnosis of Laryngeal Cancer.

BackgroundLaryngeal cancer (LaC) remains one of the most common tumors of the respiratory tract with higher incidence in men than in women. The larynx is a small but vital organ on the neck. The dysfunction of the larynx can cause serious health problems such as hoarseness, respiratory distress, and dysphonia. Many lipids (e.g. phospholipid, cholesterol, fatty acid) have been recognized as a crucial role in tumorigenesis. However, the lipid biomarkers are lacking and the lipid molecular pathogenesis of LaC is still unclear.MethodsThis study aims to identify new LaC-related lipid biomarkers used for the diagnosis or early diagnosis of LaC and to uncover their molecular characteristics. Thus, we conducted serum and tissue nontargeted lipidomics study from LaC patients (n = 29) and normal controls (NC) (n = 36) via ultra-high performance liquid chromatography (UHPLC) coupled with high resolution mass spectrometry (HRMS). Multivariate and univariate statistics analyses were used to discriminate LaC patients from NC.ResultsAs expected, a lipid panel including LPC (16:0) and PE (18:0p_20:4) was defined to distinguish the LaC patients from healthy individuals with very high diagnosis performance (area under the curve (AUC) value = 1.000, sensitivity value = 1.000, and specificity value = 1.000). In addition, the levels of Cer, CerG1, SM, PC, PC-O, PE, PI, PS, and ChE in the LaC group significantly increased as compared with the NC group. However, the levels of LPC, LPC-O, LPE, LPE-p, and DG in the LaC group significantly deceased when the one was compared with the NC group. Among significantly changed lipid species, lysophospholipids containing a palmitoyl chain or an arachidonic acid acyl chain remarkably decreased and phospholipids including a palmitoyl chain or an arachidonic acid acyl chain increased in the LaC patients.ConclusionOur results not only indicate that lipidomics is powerful tool to explore abnormal lipid metabolism for the laC, but suggest that lysophospholipids and phospholipids may serve as potential biomarkers for diagnosis of LaC.

Prediction of the Course of Transient Tachypnea of the Newborn by Blood Laboratory Parameters at the Time of Admission

Background: Transient tachypnea of the newborn (TTN) is a common but mild respiratory problem seen in late preterm and term newborns. However, it may sometimes cause severe morbidity. Objectives: Therefore, biomarkers that can predict TTN severity may aid the clinician in determining the need for intensive care. Our aim was to identify whether blood gases and complete blood count parameters could be utilized to predict the severity of TTN.s Methods: We retrospectively examined the medical records of newborns (> 37 weeks gestation, > 2000 grams) diagnosed with TTN who were hospitalized in the Neonatal Intensive Care Unit (NICU) of Karabuk University Faculty of Medicine, Training and Research Hospital, Karabük/Turkey between June 2019 and June 2020. Patients were grouped according to the length of stay in the NICU. Group 1 included patients that did not require NICU monitoring after 48 hours, and group 2 included patients who continued to require NICU monitoring after 48 hours. Blood gases and complete blood count parameters were compared between the two groups. Results: During the study period, 91 newborns were hospitalized in the NICU due to respiratory distress. Thirty-nine patients who did not meet the inclusion criteria were excluded. Gestational age and birth weight were significantly lower in group 2 (P < 0.05). There were no significant differences between the groups in terms of leukocyte count, hemoglobin level, mean platelet volume (MPV), and platelet count. Partial carbon dioxide pressure (PCO2) was significantly elevated, and base excess (BE) was significantly greater in group 2. Conclusions: We determined a relationship between a prolonged stay in NICU and the levels of PCO2 and BE among patients hospitalized with a diagnosis of TTN. Therefore, PCO2 and BE values may be valuable to determine the prognosis of TTN in the early period. Despite being one of the most common causes of intensive care admission in the newborn population, there is limited data on the diagnosis, treatment, and prognosis of TTN; thus, we believe that our results will shed light on this problem.

Combined effects of seawater acidification and benzo(a)pyrene on the physiological performance of the marine bloom-forming diatom Skeletonema costatum

The combined effects of polycyclic aromatic hydrocarbons and seawater acidification are poorly understood. Hence, we exposed the bloom-forming diatom Skeletonema costatum to four concentrations (0, 0.1, 1 and 10 μg L−1) of benzo(a)pyrene and two pCO2 levels (400 and 1000 μatm) to investigate its physiological performance. The growth and photosynthesis of S. costatum were tolerant to low and moderate benzo(a)pyrene concentrations regardless of the pCO2 level. However, the highest benzo(a)pyrene concentration had remarkably adverse effects on most parameters, decreasing the growth rate by 69%. Seawater acidification increased the sensitivity to high light stress, as shown by the lower maximum relative electron transport rate and light saturation point at the highest benzo(a)pyrene concentration. Our results suggested that benzo(a)pyrene could be detrimental to diatoms at a habitat-relevant level, and seawater acidification might further decrease its light tolerance, which would have important ramifications for the community structure and primary production in coastal waters.

Warm High‐Elevation Mid‐Latitudes During the Miocene Climatic Optimum: Paleosol Clumped Isotope Temperatures From the Northern Rocky Mountains, USA

AbstractInterrupting a long‐term Cenozoic cooling trend, the Miocene Climatic Optimum (MCO; ca. 17–15 Ma) represents a time interval characterized globally by warmer than present temperatures, lower ice volume, and elevated pCO2 levels. Establishing quantitative Neogene temperature estimates is an important element in the effort to explore the long‐term changes in the carbon cycle and associated climate feedbacks, yet terrestrial temperature records are still sparse. Here, we present a clumped isotope (Δ47) temperature record of the MCO from intermontane basins in the Northern Rocky Mountain (NRM) region. Arikareean (22.7–21.5 Ma) to Barstovian (16.9–14.7 Ma) paleosol carbonates from the Hepburn's Mesa Formation (Montana), supplemented with data from fossil localities in western Idaho. These records yield Δ47‐temperatures ranging from 17°C to 24°C, which are rather warm given the high elevation sites and are further relatively stable (mean of 21 ± 2°C) leading into and during the MCO until ca. 14.7 Ma. At ca. 14.7 Ma, we observe low Δ47‐temperatures (8°C–10°C) concomitantly with elevated Δ47‐temperatures (ca. 22°C). In line with recently suggested climate stability in the NRM region leading into the MCO, our Δ47‐temperature record, combined with carbon isotope (δ13C) and reconstructed soil water oxygen isotope (δ18Osw) values, indicates rather stable climate and environmental conditions throughout the MCO. Combining available records from inland sites in the western United States (NRM, Mojave region) points to prevailing stable continental climates even during the MCO.

Mechanical Ventilation, Partial Pressure of Carbon Dioxide, Increased Fraction of Inspired Oxygen and the Increased Risk for Adverse Short-Term Outcomes in Cooled Asphyxiated Newborns

Neonates treated with therapeutic hypothermia (TH) following perinatal asphyxia (PA) suffer a considerable rate of disability and mortality. Several risk factors associated with adverse outcomes have been identified. Mechanical ventilation might increase the risk for hyperoxia and hypocapnia in cooled newborns. We carried out a retrospective study in 71 asphyxiated cooled newborns. We analyzed the association of ventilation status and adverse short-term outcomes and investigated the effect of the former on pCO2 and oxygen delivery before, during and after TH. Death, abnormal findings on magnetic resonance imaging, and pathological amplitude-integrated electroencephalography traces were used to define short-term outcomes. The need for mechanical ventilation was significantly higher in the newborns with adverse outcomes (38% vs. 5.6%, p = 0.001). Compared to spontaneously breathing neonates, intubated newborns suffered from significantly more severe asphyxia, had significantly lower levels of mean minimum pCO2 over the first 6 and 72 h of life (HOL) (p = 0.03 and p = 0.01, respectively) and increased supply of inspired oxygen, which was, in turn, significantly higher in the newborns with adverse outcomes (p < 0.01). Intubated newborns with adverse short-term outcomes had lower levels of pCO2 over the first 36 HOL. In conclusion, need for mechanical ventilation was significantly higher in newborns with more severe asphyxia. In ventilated newborns, level of encephalopathy, lower pCO2 levels, and increased oxygen supplementation were significantly higher in the adverse short-term outcomes group. Ventilatory parameters need to be carefully monitored in cooled asphyxiated newborns.

Effects of increases in carboxyhemoglobin percent saturation and tissue hypoxia on carbon monoxide binding to canine skeletal and heart muscle extravascular tissue.

The major goal of this article was to quantify relationships of the carboxyhemoglobin % saturation, a calculated tissue PCO, and tissue hypoxia to the binding of carbon monoxide (CO) to canine skeletal and heart ventricular muscle extravascular (EV) tissue under normal conditions and during CO poisoning scenarios. These data are relevant to CO poisoning because CO bound to EV cellular hemoproteins evoke metabolic changes that produce toxic effects. Skeletal and heart muscle EV CO contents were calculated from data obtained from biopsies performed on living anesthetized dogs reported in previous publications (Coburn RF, Mayers LB. Am J Physiol 220: 66-74, 1971; Coburn RF, Ploegmakers F, Gondrie P, Abboud R. Am J Physiol 224: 870-876, 1973). Results include normal values of EV CO contents of resting skeletal muscle and heart ventricular muscle, effects of increasing COHb% saturation and a calculated mean tissue PCO on skeletal muscle EV CO binding, and effects of tissue hypoxia evoked by arterial hypoxemia on EV CO binding in both of these tissues. This study is the first that shows that tissue hypoxia-induced CO shifts out of blood resulting in increased EV CO binding are a mechanism that causes CO toxicity. Projections of results to tissue PCO levels occurring during different severe CO toxicity scenarios predict that skeletal muscle EV CO contents could increase as much as 100 to 300 fold.NEW & NEWSWORTHY This article provides quantification of some physiological parameters that determine carbon monoxide (CO) binding to skeletal and heart muscle extravascular tissue hemoproteins during normal and CO poisoning conditions. This is important information because toxicity occurring during CO poisoning is determined in part by CO binding to these proteins that results in detrimental changes in cellular metabolism.

Microbiome-mediated mechanisms contributing to the environmental tolerance of reef invertebrate species

Coral reefs globally are increasingly impacted by climate change. High temperature and pCO2 levels disrupt multiple physiological and biochemical pathways in marine organisms, often leading to disease and mortality in sensitive reef species. Host-associated microbes contribute critical functions that underpin host health, and environmentally induced changes in microbial communities represent a potential source for new metabolic features within holobiont systems. However, whether the acquisition of new beneficial microbial functions contributes to environmental acclimatisation of reef species is currently unknown. Using extensively studied model systems, we identify potential direct and indirect microbiome-mediated mechanisms that may contribute to environmental acclimatisation in reef invertebrate species. These mechanisms include increasing energy metabolism in the host, reduction of oxidative stress, regulation of nutrients in host cells, and increased pathogen resistance. We also propose a robust experimental strategy to test how microbial metabolic pathways may facilitate environmental acclimatisation of reef taxa. Understanding the mechanisms of microbiome-mediated acclimatisation and the timescales over which it can occur will be critical for predicting reef ecosystem dynamics under future climate scenarios and applying effective reef conservation strategies.

Influence of phytoplankton pigment composition and primary production on pCO2 levels in the Indian Ocean

Influence of phytoplankton pigment composition and primary production on pCO2 levels in the Indian Ocean

Dietary supplementation of methionine mitigates oxidative stress in broilers under high stocking density

We aimed to investigate whether dietary supplementation of methionine could mitigate intestinal oxidative injury in broilers under high stocking density (HSD). In the grower phase (d 22–42), 576 broilers with similar body weight were randomly chosen and divided into 8 groups in a 2 × 4 factorial experiment. Two different stocking densities (14 and 20 broilers per m2) were tested with 4 different methionine levels: 0.35%, 0.4%, 0.45%, or 0.5%. Intestinal morphological and oxidative stress markers were assessed at the end of the test period. The results showed that mortality of broilers was significantly higher in the HSD group fed 0.35% methionine diet than the other groups, which was reversed by supplementation with 0.40% to 0.50% methionine. HSD significantly decreased feed intake and daily weight gain. HSD treatment significantly decreased T-AOC, activity of GPX (P < 0.01) and increased the level of PCO (P < 0.01), MDA (P = 0.052) of plasma. The decreased glutathione peroxidase activity in the liver and jejunum caused by HSD was alleviated by additional methionine. Supplementation of methionine increased the ration of GSH/GSSG in the plasma. The jejunum villus height and ratio of villus height to crypt depth under low stocking density conditions with 0.40% methionine diet were the highest, whereas the 0.45% methionine group was the highest under HSD conditions. Thus, additional dietary supplementation of methionine mitigates oxidative stress in broilers under HSD conditions and 0.40% to 0.45% methionine can be applied in cage rearing broiler production for amelioration of oxidative stress caused by HSD.

Regulation of carbon assimilation in Skeletonema costatum under diel variations

Here, we explored the molecular responses of photosynthetic carbon fixation in a globally distributed marine diatom, Skeletonema costatum, based on incubation experiments over a 24-h period under natural light. A model of carbon metabolism was proposed based on the transcriptome of S. costatum. We examined the diurnal expression patterns and relative importance of the C4 pathway in S. costatum photosynthesis by analyzing the transcript abundance and key enzyme activities during the day/night cycle. This study suggested that the photosynthetic pathways of S. costatum were diverse and could involve combined CO2-concentrating mechanisms. The analysis at the transcriptional level revealed that the transcripts of the C4 pathway-related genes phosphoenolpyruvate carboxylase (PEPC) and pyruvate-phosphate dikinase (PPDK) were upregulated under the photoperiod and had obvious diurnal rhythms, indicating that light obviously affected photosynthetic carbon fixation. Moreover, we studied the pathway of photosynthetic carbon assimilation in S. costatum with carbon isotope δ13C techniques. The data provided evidence that carbon fixation in S. costatum involves the synergy of C3 and C4 photosynthesis. Under low pCO2 levels in the low light photoperiod, the affinity of inorganic carbon increased, supported by the C4 pathway, to acclimate to variations in the environment. This study promotes a better understanding of the photosynthetic carbon fixation mechanism in S. costatum during the diel cycle.

Exposure time modulates the effects of climate change-related stressors on fertile sporophytes and early-life stage performance of a habitat-forming kelp species

Understanding the impact of increases in pCO2 (OA) and extreme changes in temperature on marine organisms is critical to predicting how they will cope with climate change. We evaluated the effects of OA as well as warming and cooling trend temperature on early reproductive traits of Lessonia trabeculata, a bio-engineer kelp species. Sori discs were maintained for an exposure time (ET) of 3 (T3) and 7 (T7) days to one of two contrasting pCO2 levels (450 and 1100 μatm). In addition, at each pCO2 level, they were subjected to three temperature treatments: 15 °C (control), 10 °C (cool) and 19 °C (warm). Subsequently, we compared sorus photosynthetic performance (Fv/Fm), the number of meiospores released (MR) and their germination rate (GR) after 48 h of settlement, with values obtained from sori discs not exposed (DNE) to the treatments. The Fv/Fm measured for DNE was lower than at T3 and T7 at 10 and 15 °C but not at 19 °C. Regardless of temperature, we found no significant differences between MR measured at T0 and T3. MR at T7 was significantly lower at 19 °C than at 10 and 15 °C. We found only a significant reduction in MR in response to elevated pCO2 at T3. The GR of meiospores released by DNE and then maintained for 48 h to 19 °C decreased significantly by ~33% when compared with those maintained for the same time at 10 and 15 °C. A similar, but more drastic reduction (~54%) in the GR was found in meiospores released by sori discs exposed for T3 and maintained for 48 h to 19 °C. We suggest that OA and warming trend will threaten the early establishment of this species with further consequences for the functioning of the associated ecosystem.

Localized Pollution Impacts on Greenhouse Gas Dynamics in Three Anthropogenically Modified Asian River Systems

AbstractDespite growing research on greenhouse gas (GHG) emissions from inland waters, few systematic efforts have been made to assess the regional‐scale GHG emissions from Asian rivers under increasing anthropogenic stress. We examined factors controlling longitudinal and seasonal variations in the partial pressure of CO2 (pCO2), and CH4 and N2O concentrations in the Ganges, Mekong, and Yellow River by simultaneously measuring gas concentrations and stable C isotopes, and optical properties of dissolved organic matter (DOM) from 2016 to 2019. The levels of pCO2 and CH4 were distinctively higher in polluted tributaries and affected reaches of the Ganges and Mekong than in the Yellow River. The highest levels of N2O were found in the Ganges, followed by the Yellow River and Mekong. Across these basins, dry‐season mean concentrations of CO2, CH4, and N2O were 1.6, 2, and 7 times higher than those measured in the monsoon season, respectively. This seasonality was consistent with that of δ13C‐CO2, while δ13C‐CH4 showed an opposite pattern. GHG concentrations exhibited significant positive relationships with DOM concentrations and optical properties including fluorescence index and protein‐like fluorescence, implying the contribution of anthropogenic, labile DOM to production of GHGs in the polluted reaches. Graphical mixing models of δ13C‐CO2 and δ13C‐CH4 support the stronger impact of wastewater on the Ganges and Mekong than on the Yellow River. The overall results suggest that neglecting localized pollution impacts on GHG emissions from increasingly urbanized river basins can result in a substantial underestimation of global riverine GHG emissions.

Comparison of ETCO2 Value and Blood Gas PCO2 Value of Patients Receiving Non-invasive Mechanical Ventilation Treatment in Emergency Department.

Capnography is the non-invasive measurement and graphic representation of the partial pressure of CO2 in expiration. Although there are many studies in the literature comparing the partial pressure of carbon dioxide (pCO2) and end-tidal CO2 (ETCO2) values in patients who underwent IMV (invasive mechanical ventilation), there are no studies showing their interchangeable applicability in patients who received NIMV (non-IMV). We aimed to evaluate whether the use of ETCO2 in the treatment process can replace pCO2 use in patients scheduled for NIMV treatment in the emergency department. Patients who applied to the emergency department with respiratory distress between March 2019 and January 2020, who were diagnosed with acute cardiogenic edema or acute chronic obstructive pulmonary disease (COPD) exacerbation, and who needed NIMV were included in the study. General characteristics of the patients and the pCO2 and ETCO2 values were measured in the blood gas 1 h after the NIMV application was started. 64.2% (99 patients) of the patients included in the study were male, and 35.8% (55 patients) were female. The mean age of the patients included in the study was 69.1 ± 12.2 years. The mean pCO2 values ​​were measured as 52.6 ± 13.2. The mean of ETCO2 values ​​measured simultaneously was 33.6 ± 10.1. There was a significant difference between the controlled pCO2 values ​​and ETCO2 values ​​at the first hour of NIMV treatment (Z: − 10.640, p < 0.001). The ETCO2 level was found to be different in our patients who received NIMV treatment, which could not be used instead of the pCO2 level.

Ocean acidification but not elevated spring warming threatens a European seas predator

Ocean acidification has the potential to negatively affect marine ecosystems by influencing the development and metabolism of key members of food webs. The garfish, Belone belone, is an ecologically important predator in European regional seas and it remains unknown how this species will be impacted by projected changes in climate. We artificially fertilized and reared garfish embryos until hatch at present (400 μatm) and future (1300 μatm) pCO2 levels within three temperature treatments, i.e. two daily warming regimes and one constant high temperature (17 °C). For the two warming treatments, embryos were fertilized at 13 °C and experienced 0.1 or 0.3 °C/day warming. The 0.1 °C/day treatment served as control: 13 °C was the in situ temperature of parental fish in the Southwest Baltic Sea and 0.1 °C/day is the average warming rate experienced by embryos of this population in nature. Survival was drastically reduced at both future pCO2 and at the constant high temperature while the highest survival in any treatment was observed at 0.3 °C/day warming. The proportion of embryos with morphological deformities increased with elevated pCO2 but not temperature. Hatch characteristics and physiological measures such as heart rate and critical thermal ranges, however, were not affected by pCO2 but were influenced by temperature. Our results suggest that garfish in the Baltic Sea will benefit from projected increased rates of spring warming but not the concomitant increase in pCO2. Previous studies on the impacts of ocean acidification on resident fishes in the Baltic Sea indicate that this piscivorous fish is at higher risk compared to its prey which may have broader implications for the future trophodynamic structure and function of the coastal food web.

Striped catfish (Pangasianodon hypophthalmus) use air-breathing and aquatic surface respiration when exposed to severe aquatic hypercarbia.

We investigated the extent to which the facultative air-breathing fish, the striped catfish (Pangasianodon hypophthalmus), uses air-breathing to cope with aquatic hypercarbia, and how air-breathing is influenced by the experimental exposure protocol and level of hypercarbia. We exposed individuals to severe aquatic hypercarbia (up to Pw CO2 = 81 mmHg) using step-wise and progressive exposure protocols while measuring gill ventilation rate, heart rate, mean arterial blood pressure, and air-breathing frequency, as well as arterial blood pH and PCO2 . We confirm that P. hypophthalmus is tolerant of hypercarbia. Under both protocols gill ventilation rate, heart rate, and mean arterial blood pressure were maintained near control levels even at very high CO2 levels. We observed a marked amount of individual variation in the PwCO2 at which air-breathing was elicited, with some individuals not responding at all. The experimental protocol also influenced the onset of air-breathing. Air-breathing began at lower Pw CO2 in the step-wise protocol (23 ± 4.1 mmHg) compared with the progressive protocol (46 ± 7.8 mmHg). Air-breathing was often followed by aquatic surface respiration, at higher PCO2 (71 ± 5.2 mmHg) levels. On average, the blood PCO2 was approximately 43% lower (46 ± 2.5 mmHg) than water Pw CO2 (~81 mmHg) at our highest tested CO2 level. While this suggests that aerial CO2 elimination is an effective, and perhaps critical, respiratory strategy used by P. hypophthalmus to cope with severe hypercarbia, this observation may also be explained by a long lag time required for equilibration.

The dose makes the poison: Non-linear behavioural response to CO2-induced aquatic acidification in zebrafish (Danio rerio).

CO2-induced aquatic acidification is predicted to affect fish neuronal GABAA receptors leading to widespread behavioural alterations. However, the large variability in the magnitude and direction of behavioural responses suggests substantial species-specific CO2 threshold differences, life history and parental acclimation effects, experimental artifacts, or a combination of these factors. As an established model organism, zebrafish (Danio rerio) can be reared under stable conditions for multiple generations, which may help control for some of the variability observed in wild-caught fishes. Here, we used two standardized tests to investigate the effect of 1-week acclimatization to four pCO2 levels on zebrafish anxiety-like behaviour, exploratory behaviour, and locomotion. Fish acclimatized to 900 μatm CO2 demonstrated increased anxiety-like behaviour compared to control fish (~480 μatm), however, the behaviour of fish exposed to 2200 μatm CO2 was indistinguishable from that of controls. In addition, fish acclimatized to 4200 μatm CO2 had decreased anxiety-like behaviour; i.e. the opposite response than the 900 μatm CO2 treatment. On the other hand, exploratory behaviour did not differ among any of the pCO2 exposures that were tested. Thus, zebrafish behavioural responses to elevated pCO2 are not linear; with potential important implications for physiological, environmental, and aquatic acidification studies.

Umbilical Cord Blood Gas Parameters and Apgar Scoring in Assessment of New-Born Dogs Delivered by Cesarean Section.

Simple SummaryThe article presents the results of the clinical evaluation and umbilical cord blood analysis obtained from newborn pups delivered by the elective Caesarean section. In human medicine both the umbilical cord blood and Apgar score were proved to provide valuable information on neonatal status. In veterinary medicine very few reports concerning the relation between the clinical neonatal assessment (Apgar score) and umbilical cord blood parameters exist. All puppies show mild respiratory acidemia regardless the Apgar scores result. The lactates were not elevated whereas all the puppies with low Apgar sores had higher glucose and mortality rates. Only pups with low initial Apgar scores were at risk of death within first 24 h. Adaptation to the extra-uterine life is crucial and any practical improvement in neonatal diagnostics and care would be beneficial for newborn puppy survival.The article presents the results of the clinical evaluation (Apgar scores, AS) and umbilical cord blood gas analysis (UCBGA) obtained from clamped umbilical cords of newborn pups delivered by the elective Caesarean section. The study was planned as a controlled clinical study, the newborns were allocated into one of the groups, I—critical neonates (severe distress, AS ≤ 3), II—weak neonates (moderate distress, AS 4–6) and III—healthy neonates (no distress, AS ≥ 7). The following parameters were evaluated: pH (pH units), carbon dioxide partial pressure (pCO2; mmHg), oxygen partial pressure (pO2; mmHg), actual bicarbonate (cHCO3−; mmol/L), total carbon dioxide (cTCO2; mmol/L), base excess of extracellular fluid (BE(ecf); mmol/L), base excess of blood (BE(b); mmol/L), oxygen saturation (csO2; %), lactate (Lac; mg/dL), hematocrit (Hct; %PCV), hemoglobin (cHgb; g/dL), glucose (Glu; mg/dL), ions (Na, K, Ca, Cl). The majority of puppies had low AS at birth (AS 4–6 in 38.1% and AS ≤ 3 in 57.1% of the neonates), but most of them (85.7%) improved by the 20th min. reaching AS of 7 and more. Moreover, puppies with lower AS (≤ 3) were at higher risk of death within the first 24h (20.8% did not survive). The positive correlation was found between Apgar score measured at 0 min and pH (r = 0.46, p = 0.01), and between Apgar score (at 0 min) and base excess in whole blood measured [BE(b)] r = 0.36, p = 0.03). Whereas, a negative correlation was detected between Apgar score at 0 and 5th min and glycemia (r = −0.42, p = 0.05, r = −0.34, p = 0.02 respectively. Overall, the puppies with higher glucose levels had lower Apgar scores and were at higher risk of death. Furthermore, in our study, the newborn puppies had mild acidemia with elevated pCO2 levels and the HCO3 at the lower range of normal limits, suggesting the mixed component in the acidemic state. Adaptation to extra-uterine life is crucial and any practical improvement in neonatal diagnostics and care would be beneficial for newborn puppy survival.

Long-term effects of elevated pCO2 levels on the expression of Chaoborus-induced defences in Daphnia pulex

Increased carbon dioxide from fossil fuel combustion results in an enrichment of CO2 in the global carbon cycle. Recent evidence indicates that rising atmospheric CO2 impacts the partial pressure of carbon dioxide (pCO2) in freshwaters. This affects freshwater biota by disrupting chemical communication between predator and prey. One such well-described predator–prey interaction is the phantom midge larva Chaoborus preying on the freshwater crustacean Daphnia pulex. To counter Chaoborus predation, D. pulex develops defensive neckteeth in response to chemical cues. The strength of neckteeth expression is reduced when D. pulex experience elevated pCO2 levels. This is discussed to directly impair predator perception and results in reduced defence expression. However, it is not known whether there are also long-term effects associated with continuous elevated pCO2. Here, we investigated the effect of long-term exposure of D. pulex to elevated pCO2 levels in a life-table experiment over three generations. Using a flow-through system, we continuously exposed D. pulex to cues released by the predatory larva Chaoborus and control or elevated pCO2 levels. We determined morphological defence expression in the 2nd juvenile instar and the number of neonates as a measure for life-history traits over three successive generations. We detected that elevated pCO2 significantly reduces the expression of predator-induced morphological defences (i.e. neckteeth) and life-history parameters (i.e. number of neonates) in successive generations. Our data clearly show that at least three generations become more vulnerable to predation without indications of transgenerational acclimation. As Daphnia is a keystone grazer of freshwater ecosystems, this may destabilise population growth rates. In conclusion, long-term effects of pCO2-induced reduction of predator-induced plasticity may significantly affect trophic interactions.

Ocean acidification compromises energy management in Sparus aurata (Pisces: Teleostei)

The effects of ocean acidification mediated by an increase in water pCO2 levels on marine organisms are currently under debate. Elevated CO2 concentrations in the seawater induce several physiological responses in teleost fish, including acid-base imbalances and osmoregulatory changes. However, the consequences of CO2 levels enhancement on energy metabolism are mostly unknown. Here we show that 5 weeks of exposure to hypercapnia (950 and 1800 μatm CO2) altered intermediary metabolism of gilthead seabream (Sparus aurata) compared to fish acclimated to current ocean values (440 μatm CO2). We found that seabream compromises its physiological acid-base balance with increasing water CO2 levels and the subsequent acidification. Intestinal regions (anterior, mid, and rectum) engaged in maintaining this balance are thus altered, as seen for Na+/K+-ATPase and the vacuolar-type H+-ATPase activities. Moreover, liver and muscle counteracted these effects by increasing catabolic routes e.g., glycogenolysis, glycolysis, amino acid turnover, and lipid catabolism, and plasma energy metabolites were altered. Our results demonstrate how a relatively short period of 5 weeks of water hypercapnia is likely to disrupt the acid-base balance, osmoregulatory capacity and intermediary metabolism in S. aurata. However, long-term studies are necessary to fully understand the consequences of ocean acidification on growth and other energy-demanding activities, such as reproduction.

Ecotoxicological evaluation of water from the Sorocaba River using an integrated analysis of biochemical and morphological biomarkers in bullfrog tadpoles, Lithobates catesbeianus ( )

Lithobates catesbeianus tadpoles were exposed for 96 h to water from two sites of the Sorocaba River (summer and winter), Ibiúna (PI) and Itupararanga reservoir (PIR) that contained metals. In the liver, in PI, the glutathione peroxidase (GPx) decreased, and the glutathione S-transferase (GST) and carbonyl proteins (PCO) increased. In PIR, the glutathione reduced (GSH) increased, while there was a decrease in catalase (CAT), GPx, GST, PCO, and superoxide dismutase (SOD). In winter, GPx and GST increased in both points. Regarding the kidneys, lipoperoxidation (LPO) levels and GST decreased, while GSH increased in the summer. In the winter, LPO increased in PI. In the muscle, in the summer, there was an increase in GSH and GST and change in PCO. In the winter, the levels of PCO increased and CAT decreased in PIR. The area and volume of the hepatocyte and nucleus area increased in the summer and decreased in the winter. Hepatic melanin decreased in the summer after exposure to PIR water. There were the systemic effects of Sorocaba River water exposure at different times of the year with alterations in biomarkers at different levels, in which kidney shows highest Integrated Response of Biomarkers (IBR) value followed by liver and muscle. Biochemical biomarkers were more sensitive than morphological ones. The more sensitive biochemical markers were MT, PCO, GST and LPO. These effects confirm the hypothesis of metabolic alteration in bullfrog tadpoles by the Sorocaba River water.