Antioxidant defense response during hibernation and arousal in Chinese soft-shelled turtle Pelodiscus sinensis juveniles.

Antioxidant defense is essential for animals to cope with homeostasis disruption during hibernation. The present study aimed to investigate the antioxidant defense response of juvenile soft-shelled turtle Pelodiscus sinensis during hibernation and following arousal. Turtle brain, liver, and kidney samples were collected at pre-hibernation (17 °C mud temperature; MT), during hibernation (5.8 °C MT) and after arousal (20.1 °C MT) in the field. Transcript levels of NF-E2-related factor 2 (Nrf2) decreased significantly during hibernation and recovered after arousal in all tissues. Cerebral and nephric copper-zinc superoxide dismutase (Cu/Zn SOD), catalase (CAT), glutathione peroxidase 3 (GPx3) and nephric GPx4 mRNA showed similar changing patterns as Nrf2. Cerebral Mn SOD, GPx1 and nephric GPx1 up-regulated after arousal. Hepatic Cu/Zn SOD, GPx1 and GPx3 mRNA kept stable, except hepatic GPx4 increased during hibernation. Hepatic Mn SOD and CAT increased after arousal. In the GSH system, mRNA levels of glutathione synthetases (GSs) kept stable during hibernation and up-regulated after arousal in most tissues except nephric GS2 mRNA remained unchanged. Gene expressions of glutathione reductase (GR) exhibited a tissue specific changing pattern, while those of glutathione-S-Transferase (GST) shared a similar pattern among tissues: remained stable or down-regulated during hibernation then recovered in arousal. In contrast to these diverse responses in gene expressions, most of the antioxidant enzyme activities maintained high and stable. Overall, no preparation for oxidative stress (POS) strategy was found in enzymatic antioxidant system in P. sinensis juveniles during hibernation, the Chinese soft-shelled turtles were able to stay safe from potential oxidative stress during hibernation by maintaining high level activities/concentrations of the antioxidant enzymes/antioxidants.

Antioxidant response to acute cold exposure and during recovery in juvenile Chinese soft-shelled turtles (Pelodiscus sinensis).

The antioxidant defense protects turtles from oxidative stress caused by adverse environment conditions, such as acute thermal fluctuations. However, it remains unclear how these defenses work. The present study examined changes in key enzymes of the enzymatic antioxidant system and the glutathione (GSH) system at both the mRNA and enzyme activity levels during acute cold exposure and recovery in juvenile Chinese soft-shelled turtles, Pelodiscus sinensis Transcript levels of the upstream regulator NF-E2-related factor 2 (Nrf2) were also measured. Turtles were acclimated at 28°C (3 weeks), then given acute cold exposure (8°C, 12 h) and finally placed in recovery (28°C, 24 h). The mRNA levels of cerebral and hepatic Nrf2 and of genes encoding downstream antioxidant enzymes did not change, whereas levels of nephric Nrf2, manganese superoxide dismutase (MnSOD) and glutathione peroxidase 4 (GPx4) mRNA decreased upon cold exposure. During recovery, Nrf2 mRNA remained stable in all three tissues, hepatic Cu/ZnSOD, MnSOD and catalase (CAT) mRNA levels increased, and nephric MnSOD and GPx4 mRNAs did not change from the values during cold exposure. In the GSH system, mRNA levels of most enzymes remained constant during cold exposure and recovery. Unmatched with changes in mRNA level, high and stable constitutive antioxidant enzyme activities were maintained throughout, whereas GPx activity significantly reduced in the kidney during cold exposure, and in liver and kidney during recovery. Our results suggest that the antioxidant defense regulation in response to acute cold exposure in P. sinensis may not be achieved at the transcriptional level, but may rely mainly on high constitutive antioxidant enzyme activities.

Digital Gene Expression Profiling reveals transcriptional responses to acute cold stress in Chinese soft-shelled turtle Pelodiscus sinensis juveniles.

Turtles are well known for their stress tolerance, including an ability to deal with temperature extremes or rapid thermal change. To know more about the comprehensive molecular basis of thermal stress responses in turtles, we assessed differentially expressed genes (DEGs) in the brain, liver and kidney of juvenile soft-shelled turtles, Pelodiscus sinensis, after acute cold stress (28 °C-8 °C acute transfer and held for 12 h) and following recovery (back to 28 °C and held for 24 h) by digital gene expression profiling. Selected DEGs were also validated via real-time PCR. We found the fewest DEGs in the brain, only one-tenth of the number seen in liver, indicating a tissue-specific gene expression pattern. The DEGs indicated the potential activation of several important functions in response to cold stress and recovery in P. sinensis. This included response to oxidative stress or regulation of reactive oxygen species metabolism in the brain and liver, cerebral inositol metabolism, hepatic monosaccharide metabolism, hepatic complement system, renal DNA repair mechanisms, and TNF and PI3K-Akt signaling pathways in the kidney. These functions likely responded to cold stress in different tissues of P. sinensis to help minimize or repair cell damage as well as enhance innate immunity. The outcomes of this study provide some fundamental insight into the tissue specific complex mechanisms underlining cold stress responses in the soft-shelled turtle P. sinensis.

Antioxidant responses in hibernating Chinese soft-shelled turtle Pelodiscus sinensis hatchlings.

The antioxidant defense system protects turtles from oxidative stress during hibernation. The present study examined changes of the antioxidant enzymes both on mRNA level and enzyme activity level during hibernation of Chinese soft-shelled turtle Pelodiscus sinensis hatchlings. The upstream regulator NF-E2 related factor 2 (Nrf2) mRNA was also measured. Samples were taken at pre-hibernation (17.0°C, Mud temperature (MT)), hibernation (5.8°C, MT) and arousal (20.1°C, MT). Nrf2 exhibited a tissue-specific pattern of expression with a decrease in the brain, slight increase in the liver and heart during hibernation, and significant increase during arousal in all the three tissues. Superoxide dismutase (SOD) mRNA, catalase (CAT) mRNA, and glutathione peroxidase 3 (GPx3) mRNA exhibited a similar pattern as Nrf2 in the brain and liver during the entire hibernation period. Hepatic GPx4 mRNA level increased during hibernation and decreased during arousal, whereas it did not change in the heart. Cerebral SOD and CAT activities kept stable during the experimental period, but GPx activity decreased significantly during hibernation and arousal. Hepatic GPx enzyme activity did not change, whereas those of SOD and CAT exhibited a notable decrease during arousal. Malondialdehyde concentration did not increase during the hibernation process, indicating an effective protection of the antioxidant defense system.

Freeform microstructure linear light emitter design for a natural light illumination system.

The major factors of an illuminative environment are a high rendering index and uniformity. The natural light illumination system (NLIS) is used to guide sunlight for indoor illumination. The NLIS consists of three subsystems: collecting, transmitting, and emitting. Nowadays, a variety of light emitters are available for different illuminative environments. This paper proposes a linear microstructure to diffuse parallel light for indoor illumination. To increase uniformity and promote the illuminative area, the light emitter includes two microstructures for the distribution of light. Finally, the proposed light emitter gives illuminance uniformity and efficiency of 0.55% and 74.18%, respectively.

Innovative light collimator with afocal lens and total internal reflection lens for daylighting system.

This research presents a novel design of the collimator, which uses total internal reflection (TIR), convex, and concave lenses for the natural light illumination system (NLIS). The concept of the NLIS is to illuminate building interiors with natural light, which saves energy consumption. The TIR lens is used to collimate the light, and convex and concave lenses are used to converge the light to the required area. The results have shown that the efficiency in terms of achieving collimated light using the proposed collimator at the output of the light collector is better than that of a previous system without a collimator.

Ascorbic acid regulation in stress responses during acute cold exposure and following recovery in juvenile Chinese soft-shelled turtle (Pelodiscus sinensis).

Intense temperature change often leads to increased oxidative stress in many animals with a few exceptions, including the turtle. To date, little is known about the mechanism of protective antioxidative defenses in turtles during acute temperature change, specifically the role that the antioxidant ascorbic acid (AA) plays. In this study, Chinese soft-shelled turtles (Pelodiscus sinensis) were initially acclimated at 28°C (3 wks), exposed to acute cold condition (8°C, 8 h) and finally placed in recovery (28°C, 24 h). L-Gulonolactone oxidase (GLO) mRNA exhibited a stable transcription pattern during the intense thermal fluctuation. GLO activity also remained stable, which validated the mRNA expression pattern. The similar Q10 values for GLO activity in the different treatment groups at incubation temperatures of 28°C and 8°C indicated that the GLO activity response to thermal change exhibited a temperature-dependent enzymatic kinetic characteristic. The AA storage was tissue-specific as well as the AA re-supply in the recovery period, with brain as the priority. Despite the insufficient transport during cold exposure, the plasma AA reservoir greatly contributed to the redistribution of AA during recovery. Depending on the prominent GLO activity, the high level of tissue-specific AA storage and the extraordinary plasma AA transport potential, the Chinese soft-shelled turtle endured severe thermal fluctuations with no apparent oxidative stress. However, the significant decrease in AA concentration in the brain tissue during acute cold exposure suggested that such a strategy may not be sufficient for prolonged cold exposure.

Nutritional and Feeding Adaptability of Clanis bilineata tsingtauica Larvae to Different Cultivars of Soybean, (Glycine max).

The larvae of Clanis bilineata tsingtauica, a special species of Chinese edible insect, are of great nutritional, medicinal and economic value to humans. This study aimed to clarify the effect of different soybean varieties (Guandou-3 (G3), Ruidou-1 (R1), September cold (SC)) on the nutritional quality and feeding selection behavior of C. bilineata tsingtauica larvae. The results showed that soybean isoleucine (Ile) and phenylalanine (Phe) were positively correlated with larval host selection (HS) and protein content. The order of soybean plants selected by C. bilineata tsingtauica larvae was R1 > SC > G3, and they selected R1 significantly higher than SC and G3 by 50.55% and 109.01%, respectively. The protein content of the larvae fed on R1 was also the highest among the three cultivars. In addition, a total of 17 volatiles belonging to 5 classes were detected from soybeans: aldehydes, esters, alcohols, ketones, and heterocyclic compounds. Pearson's analysis showed that soybean methyl salicylate was positively correlated with larval HS and their protein content, and soybean 3-octenol was negatively correlated with larval HS and their palmitic acid content. In conclusion, C. bilineata tsingtauica larvae are more adapted to R1 than to the other two soybean species. This study provides a theoretical basis for the production of more protein-rich C. bilineata tsingtauica in the food industry.

TM7 (Saccharibacteria) regulates the synthesis of linolelaidic acid and tricosanoic acid, and alters the key metabolites in diapause Clanis bilineata tsingtauica.

Good exploitation and utilization of edible insects can effectively alleviate global food security crisis in years. The study on diapause larvae of Clanis bilineata tsingtauica (DLC) was conducted to explore how gut microbiota regulate the nutrients synthesis and metabolism of edible insects. The results showed that C. bilineata tsingtauica maintained a total and stable nutrition levels at early phase of diapause. The activity of instetinal enzymes in DLC fluctuated markedly with diapause time. Additionally, Proteobacteria and Firmicutes were the predominant taxa, and TM7 (Saccharibacteria) was the marker species of gut microbiota in DLC. Combined the gene function prediction analysis with Pearson correlation analysis, TM7 in DLC was mainly involved in the biosynthesis of diapause-induced differential fatty acids, i.e., linolelaidic acid (LA) and tricosanoic acid (TA), which was probably regulated by changing the activity of protease and trehalase, respectively. Moreover, according to the non-target metabolomics, TM7 might regulate the significant differential metabolites, i.e., D-glutamine, N-acetyl-d-glucosamine and trehalose, via the metabolism of amino acid and carbohydrate pathways. These results suggest that TM7 increased LA and decreased TA via the intestinal enzymes, and altered intestinal metabolites via the metabolism pathways, maybe a key mechanism for regulating the nutrients synthesis and metabolisms in DLC.

Fuel source shift or cost reduction: Context-dependent adaptation strategies in closely related Neodon fuscus and Lasiopodomys brandtii against hypoxia.

Oxygen is essential for most life forms. Insufficient oxygen supply can disrupt homeostasis and compromise survival, and hypoxia-induced cardiovascular failure is fatal in many animals, including humans. However, certain species have adapted and evolved to cope with hypoxic environments and are therefore good models for studying the regulatory mechanisms underlying responses to hypoxia. Here, we explored the physiological and molecular responses of the cardiovascular system in two closely related hypoxia-adapted species with different life histories, namely, Qinghai voles ( Neodon fuscus) and Brandt's voles ( Lasiopodomys brandtii), under hypoxic (10% O 2 for 48 h) and normoxic (20.9% O 2 for 48 h) exposure. Kunming mice ( Mus musculus) were used for comparison. Qinghai voles live in plateau areas under hypoxic conditions, whereas Brandt's voles only experience periodic hypoxia. Histological and hematological analyses indicated a strong tolerance to hypoxia in both species, but significant cardiac tissue damage and increased blood circulation resistance in mice exposed to hypoxia. Comparative transcriptome analysis revealed enhanced oxygen transport efficiency as a coping mechanism against hypoxia in both N. fuscus and L. brandtii, but with some differences. Specifically, N. fuscus showed up-regulated expression of genes related to accelerated cardiac contraction and angiogenesis, whereas L. brandtii showed significant up-regulation of erythropoiesis-related genes. Synchronized up-regulation of hemoglobin synthesis-related genes was observed in both species. In addition, differences in cardiometabolic strategies against hypoxia were observed in the rodents. Notably, M. musculus relied on adenosine triphosphate (ATP) generation via fatty acid oxidation, whereas N. fuscus shifted energy production to glucose oxidation under hypoxic conditions and L. brandtii employed a conservative strategy involving down-regulation of fatty acid and glucose oxidation and a bradycardia phenotype. In conclusion, the cardiovascular systems of N. fuscus and L. brandtii have evolved different adaptation strategies to enhance oxygen transport capacity and conserve energy under hypoxia. Our findings suggest that the coping mechanisms underlying hypoxia tolerance in these closely related species are context dependent.

The effects of dissolved oxygen level on the metabolic interaction between digestion and locomotion in juvenile southern catfish (Silurus meridionalis Chen).

To investigate the effect of dissolved oxygen level ([O(2)]) on maintenance metabolism, feeding metabolism, aerobic swimming performance and their metabolic interaction in juvenile southern catfish (Silurus meridionalis Chen), we measured the following: (1) the resting oxygen consumption rate (MO(2rest)) over a range of water [O(2)] and from this we calculated the critical oxygen tension (P(crit)) of fasting fish; (2) the postprandial MO(2) response (10% body mass meal size) at water [O(2)] of 1, 2, 4 and 8mgO(2)L(-1); and (3) the swimming performance of fasting and digesting fish at water [O(2)] of 1, 2, 4 and 8mgO(2)L(-1) at 25 degrees C. The MO(2rest) remained constant over a broad range of water [O(2)] but then dropped markedly upon reaching the P(crit) (16.4% saturation). Hypoxic groups presented lower peak postprandial MO(2) (MO(2peak)) (1mgO(2)L(-1) group), larger energy expenditure and longer digestive process (both 1 and 2mgO(2)L(-1)) than those of normoxic groups. Both critical swimming speed (U(crit)) and the active metabolic rate (MO(2active)) of fasting fish remained unchanged over a decrease in water [O(2)] from 8 to 4mgO(2)L(-1) and then decreased significantly with further decreases in water [O(2)]. These parameters in fed fish showed a pronounced decrease as water [O(2)] decreased from 8 to 1mgO(2)L(-1). Feeding caused a significantly lower U(crit) in the 2mgO(2)L(-1) water [O(2)] group, a significantly higher MO(2active) in both the 2 and 8mgL(-1) water [O(2)] groups and a significantly higher metabolic scope (MO(2active)-MO(2rest)) in both the 2 and 4mgO(2)L(-1) water [O(2)] groups compared to fasting fish. The MO(2) increased greatly with swimming speed in the higher water [O(2)] groups, whereas it leveled off as swimming speeds approached the U(crit) in the lower water [O(2)] groups. Within all water [O(2)] groups, feeding caused a higher MO(2) compared to fasting fish when fish swam at the same speeds, except in the 1mgO(2)L(-1) group. This finding showed that the critical water [O(2)] for maintenance of metabolism, digestion, swimming and postprandial swimming increased sequentially due to the increasing O(2) demand, which challenges respiratory capacity. With the administration of the medium-sized meal that was used in this study, the metabolic mode of juvenile southern catfish changed from an additive mode during normoxia to a digestion-priority mode under moderate hypoxia and to locomotion-priority mode under hypoxia.

Failure of Less-Invasive Stabilization System (LISS) plating for periprosthetic distal femur fractures: Three case reports.

RATIONALE: Less-Invasive Stabilization System (LISS) plate is an internal fixation commonly used for the periprosthetic distal femur fractures. Failure associated with LISS plate has been rarely reported, and the reasons for LISS plate failure are multitudinous. Various advantages have been reported, but failures continue. PATIENT CONCERNS: We present 3 cases illustrating the failure of Less-Invasive Stabilization System (LISS) plating for periprosthetic distal femur fractures. The shaft screws of the LISS plate broke in 2 cases, and the plate placement was incorrect in 1 case. Early weight bearing, obesity, osteoporosis, and lateral collateral ligament injury due to incorrect plate placement constituted the etiologies of LISS plate failure. DIAGNOSIS: Failure of Less-Invasive Stabilization System (LISS) plating for periprosthetic distal femur fractures after Total knee arthroplasty. INTERVENTIONS: Three patients underwent Less-Invasive Stabilization System plates removal with replacement of the total knee arthroplasty revision surgery with rotating hinged knee prosthesis. OUTCOMES: After completing the total knee arthroplasty revision surgery, all patients underwent regular follow-up examinations. Case 2 could walk unaided, without pain, final union was confirmed for both case 1 and case 3. CONCLUSION: Less-Invasive Stabilization System (LISS) plate provides satisfactory results in periprosthetic fractures after Total knee arthroplasty (TKA). The LISS plate has many advantages, but failures continue to occur. The causes for failure were early weight bearing, obesity, osteoporosis, and lateral collateral ligament (LCL) injury due to incorrect plate placement in our series. We recommend that protection or properly delay of weight-bearing, active anti-osteoporosis treatment, and intraoperative fluoroscopy are the effective methods to avoid failure.

Predator-induced changes of male and female mating preferences: innate and learned components.

While many mating preferences have a genetic basis, the question remains as to whether and how learning/experience can modify individual mate choice decisions. We used wild-caught (predator-experienced) and F1 laboratory-reared (predator-naïve) invasive Western mosquitofish Gambusia affinis from China to test whether mating preferences (assessed in a first mate choice test) would change under immediate predation threat. The same individuals were tested in a second mate choice test during which 1 of 3 types of animated predators was presented: 1) a co-occurring predator, 2) a co-evolved but not currently co-occurring predator, and 3) a non-piscivorous species as control. We compared preference scores derived from both mate choice tests to separate innate from experiential effects of predation. We also asked whether predator-induced changes in mating preferences would differ between sexes or depend on the choosing individual's personality type and/or body size. Wild-caught fish altered their mate choice decisions most when exposed to the co-occurring predator whereas laboratory-reared individuals responded most to the co-evolved predator, suggesting that both innate mechanisms and learning effects are involved. This behavior likely reduces individuals' risk of falling victim to predation by temporarily moving away from high-quality (i.e., conspicuous) mating partners. Accordingly, effects were stronger in bolder than shyer, large- compared with small-bodied, and female compared with male focal individuals, likely because those phenotypes face an increased predation risk overall. Our study adds to the growing body of literature appreciating the complexity of the mate choice process, where an array of intrinsic and extrinsic factors interacts during decision-making.

Personality differentially affects individual mate choice decisions in female and male Western mosquitofish (Gambusia affinis).

Consistent individual differences in behavioral tendencies (animal personality) can affect individual mate choice decisions. We asked whether personality traits affect male and female mate choice decisions similarly and whether potential personality effects are consistent across different mate choice situations. Using western mosquitofish (Gambusia affinis) as our study organism, we characterized focal individuals (males and females) twice for boldness, activity, and sociability/shoaling and found high and significant behavioral repeatability. Additionally, each focal individual was tested in two different dichotomous mate choice tests in which it could choose between computer-animated stimulus fish of the opposite sex that differed in body size and activity levels, respectively. Personality had different effects on female and male mate choice: females that were larger than average showed stronger preferences for large-bodied males with increasing levels of boldness/activity (i.e., towards more proactive personality types). Males that were larger than average and had higher shoaling tendencies showed stronger preferences for actively swimming females. Size-dependent effects of personality on the strength of preferences for distinct phenotypes of potential mating partners may reflect effects of age/experience (especially in females) and social dominance (especially in males). Previous studies found evidence for assortative mate choice based on personality types or hypothesized the existence of behavioral syndromes of individuals' choosiness across mate choice criteria, possibly including other personality traits. Our present study exemplifies that far more complex patterns of personality-dependent mate choice can emerge in natural systems.

Interspecific differences in hypoxia-induced gill remodeling in carp.

The gills of many fish, but in particular those of crucian carp (Carassius carassius) and goldfish (Carassius auratus), are capable of extensive remodeling in response to changes in oxygen (O2), temperature, and exercise. In this study, we investigated the interspecific variation in hypoxia-induced gill modeling and hypoxia tolerance in 10 closely related groups of cyprinids (nine species, with two strains of Cyprinus carpio). There was significant variation in hypoxia tolerance, measured as the O2 tension (P(O2)) at which fish lost equilibrium (LOEcrit), among the 10 groups of carp. In normoxia, there was a significant, phylogenetically independent relationship between mass-specific gill surface area and LOEcrit, with the more hypoxia-tolerant carp having smaller gills than their less hypoxia-tolerant relatives. All groups of carp, except the Chinese bream (Megalobrama pellegrini), increased mass-specific gill surface area in response to 48 h of exposure to hypoxia (0.7 kPa) through reductions in the interlamellar cell mass (ILCM) volume. The magnitude of the hypoxia-induced reduction in the ILCM was negatively correlated with LOEcrit (and thus positively correlated with hypoxia tolerance), independent of phylogeny. The hypoxia-induced changes in gill morphology resulted in reduced variation in mass-specific gill surface area among species and eliminated the relationship between LOEcrit and mass-specific gill surface area. While behavioral responses to hypoxia differed among the carp groups, there were no significant relationships between hypoxia tolerance and the Po2 at which aquatic surface respiration (ASR) was initiated or the total number of ASR events observed during progressive hypoxia. Our results are the first to show that the extent of gill remodeling in cyprinids is associated with hypoxia tolerance in a phylogenetically independent fashion.