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Sample records for aestivation

  1. Understanding mechanism of sea cucumber Apostichopus japonicus aestivation: Insights from TMT-based proteomic study.

    Science.gov (United States)

    Chen, Muyan; Li, Xingke; Zhu, Aijun; Storey, Kenneth B; Sun, Lina; Gao, Tianxiang; Wang, Tianming

    2016-09-01

    Marine invertebrate aestivation is a unique strategy for summer survival in response to hot marine conditions. The sea cucumber, Apostichopus japonicus, is an excellent model marine invertebrate for studies of environmentally-induced aestivation. In the present study, we used a tandem mass tag (TMT)-coupled LC-MS/MS approach to identify and quantify the global proteome expression profile over the aestivation-arousal cycle of A. japonicus. A total of 3920 proteins were identified from the intestine of sea cucumber. Among them, 630 proteins showed significant differential expression when comparing three conditions of sea cucumbers: non-aestivating (active), deep-aestivation (at least 15days of continuous aestivation), and arousal after aestivation (renewed moving and feeding). Sea cucumbers in deep aestivation showed substantial differentially expressed proteins (143 up-regulated and 267 down-regulated proteins compared with non-aestivating controls). These differentially expressed proteins suggested that protein and phospholipid probably are major fuel sources during hypometabolism and a general attenuation of carbohydrate metabolism was observed during deep aestivation. Differentially expressed proteins also provided the first global picture of a shift in protein synthesis, protein folding, DNA binding, apoptosis, cellular transport and signaling, and cytoskeletal proteins during deep aestivation in sea cucumbers. A comparison of arousal from aestivation with deep aestivation, revealed a general reversal of the changes that occurred in aestivation for most proteins. Western blot detection further validated the significant up-regulation of HSP70 and down-regulation of methyltransferase-like protein 7A-like in deep-aestivation. Our results suggest that there is substantial post-transcriptional regulation of proteins during the aestivation-arousal cycle in sea cucumbers.

  2. Water management by dormant insects: comparisons between dehydration resistance during summer aestivation and winter diapause.

    Science.gov (United States)

    Benoit, Joshua B

    2010-01-01

    During summer in temperate regions and tropical dry seasons insects are exposed to extended periods with little available water. To counter this dehydration stress, insects have two options. They can either remain active by utilizing mechanisms to function under severe water stress and high temperatures, or they can escape from the stressful environment by exploiting an aestivation mechanism. During aestivation, insects undergo a variety of molecular and biochemical changes to arrest development, reduce metabolism, tolerate high temperatures, and increase their ability to maintain water balance. In this review, I provide a synopsis of known and possible mechanisms utilized by insects to reduce the stress of dehydration during aestivation. Comparative observations of aestivating and diapausing insects are also discussed to assess similarities and differences in the methods used by insects to increase dehydration resistance between these two types of dormancies. Adaptations that alter moisture requirements during diapause (low metabolic rate, increases in osmolytes, shifts in cuticular hydrocarbons, cell membrane restructing) are likely similar to those utilized at the induction and during the maintenance phase of aestivation. Few studies have been conducted on the physiology, particularly the biochemistry and molecular regulation, of aestivating insects, indicating that much more research is needed to fully assess water balance characteristics of insects during aestivation. Whether an insect is in diapause or aestivation, behavioral, biochemical, and physiological adaptations are essential for suppressing water loss and enhancing survival in a desiccated state.

  3. Enzyme activity in the aestivating green-striped burrowing frog (Cyclorana alboguttata).

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    Mantle, Beth L; Guderley, Helga; Hudson, Nicholas J; Franklin, Craig E

    2010-10-01

    Green-striped burrowing frogs (Cyclorana alboguttata) can depress their resting metabolism by more than 80% during aestivation. Previous studies have shown that this species is able to withstand long periods of immobilisation during aestivation while apparently maintaining whole muscle mass and contractile performance. The aim of this study was to determine the effect of prolonged aestivation on the levels of metabolic enzymes (CCO, LDH and CS) in functionally distinct skeletal muscles (cruralis, gastrocnemius, sartorius, iliofibularis and rectus abdominus) and liver of C. alboguttata. CS activity was significantly reduced in all tissues except for the cruralis, gastrocnemius and the liver. LDH activity was significantly reduced in the sartorius and rectus abdominus, but remained at control (active) levels in the other tissues. CCO activity was significantly reduced in the gastrocnemius and rectus abdominus, and unchanged in the remaining tissues. Muscle protein was significantly reduced in the sartorius and iliofibularis during aestivation, and unchanged in the remaining muscles. The results suggest that the energy pathways involved in the production and consumption of ATP are remodelled during prolonged aestivation but selective. Remodelling and subsequent down-regulation of metabolic activity seem to target the smaller non-jumping muscles, while the jumping muscles retain enzyme activities at control levels during aestivation. These results suggest a mechanism by which aestivating C. alboguttata are able to maintain metabolic depression while ensuring that the functional capacity of critical muscles is not compromised upon emergence from aestivation.

  4. Skeletal muscle atrophy occurs slowly and selectively during prolonged aestivation in Cyclorana alboguttata (Gunther 1867).

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    Mantle, Beth L; Hudson, Nicholas J; Harper, Gregory S; Cramp, Rebecca L; Franklin, Craig E

    2009-11-01

    We investigated the effect of prolonged immobilisation of six and nine months duration on the morphology and antioxidant biochemistry of skeletal muscles in the amphibian aestivator Cyclorana alboguttata. We hypothesised that, in the event of atrophy occurring during aestivation, larger jumping muscles were more likely to be preserved over smaller non-jumping muscles. Whole muscle mass (g), muscle cross-sectional area (CSA) (microm(2)), water content (%) and myofibre number (per mm(2)) remained unchanged in the cruralis muscle after six to nine months of aestivation; however, myofibre area (microm(2)) was significantly reduced. Whole muscle mass, water content, myofibre number and myofibre CSA remained unchanged in the gastrocnemius muscle after six to nine months of aestivation. However, iliofibularis dry muscle mass, whole muscle CSA and myofibre CSA was significantly reduced during aestivation. Similarly, sartorius dry muscle mass, water content and whole muscle CSA was significantly reduced during aestivation. Endogenous antioxidants were maintained at control levels throughout aestivation in all four muscles. The results suggest changes to muscle morphology during aestivation may occur when lipid reserves have been depleted and protein becomes the primary fuel substrate for preserving basal metabolic processes. Muscle atrophy as a result of this protein catabolism may be correlated with locomotor function, with smaller non-jumping muscles preferentially used as a protein source during fasting over larger jumping muscles. Higher levels of endogenous antioxidants in the jumping muscles may confer a protective advantage against oxidative damage during aestivation; however, it is not clear whether they play a role during aestivation or upon resumption of normal metabolic activity.

  5. Differential gene expression in the liver of the African lungfish, Protopterus annectens, after 6 months of aestivation in air or 1 day of arousal from 6 months of aestivation.

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    Kum C Hiong

    Full Text Available The African lungfish, Protopterus annectens, can undergo aestivation during drought. Aestivation has three phases: induction, maintenance and arousal. The objective of this study was to examine the differential gene expression in the liver of P. annectens after 6 months (the maintenance phase of aestivation as compared with the freshwater control, or after 1 day of arousal from 6 months aestivation as compared with 6 months of aestivation using suppression subtractive hybridization. During the maintenance phase of aestivation, the mRNA expression of argininosuccinate synthetase 1 and carbamoyl phosphate synthetase III were up-regulated, indicating an increase in the ornithine-urea cycle capacity to detoxify ammonia to urea. There was also an increase in the expression of betaine homocysteine-S-transferase 1 which could reduce and prevent the accumulation of hepatic homocysteine. On the other hand, the down-regulation of superoxide dismutase 1 expression could signify a decrease in ROS production during the maintenance phase of aestivation. In addition, the maintenance phase was marked by decreases in expressions of genes related to blood coagulation, complement fixation and iron and copper metabolism, which could be strategies used to prevent thrombosis and to conserve energy. Unlike the maintenance phase of aestivation, there were increases in expressions of genes related to nitrogen, carbohydrate and lipid metabolism and fatty acid transport after 1 day of arousal from 6 months aestivation. There were also up-regulation in expressions of genes that were involved in the electron transport system and ATP synthesis, indicating a greater demand for metabolic energy during arousal. Overall, our results signify the importance of sustaining a low rate of waste production and conservation of energy store during the maintenance phase, and the dependence on internal energy store for repair and structural modification during the arousal phase, of

  6. Effect of prolonged inactivity on skeletal motor nerve terminals during aestivation in the burrowing frog, Cyclorana alboguttata.

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    Hudson, Nicholas J; Lavidis, Nickolas A; Choy, Peng T; Franklin, Craig E

    2005-04-01

    This study examined the effect of prolonged inactivity, associated with aestivation, on neuromuscular transmission in the green-striped burrowing frog, Cyclorana alboguttata. We compared the structure and function of the neuromuscular junctions on the iliofibularis muscle from active C. alboguttata and from C. alboguttata that had been aestivating for 6 months. Despite the prolonged period of immobility, there was no significant difference in the shape of the terminals (primary, secondary or tertiary branches) or the length of primary terminal branches between aestivators and non-aestivators. Furthermore, there was no significant difference in the membrane potentials of muscle fibres or in miniature end plate potential (EPP) frequency and amplitude. However, there was a significant decrease in evoked transmitter release characterised by a 56% decrease in mean EPP amplitude, and a 29% increase in the failure rate of nerve terminal action potentials to evoke transmitter release. The impact of this suite of neuromuscular characteristics on the locomotor performance of emergent frogs is discussed.

  7. Aestivation and diapause syndromes reduce the water balance requirements for pupae of the Hessian fly, Mayetiola destructor.

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    We report the water balance of aestivating (summer), diapausing (winter), and non-diapausing pupae of Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae). Maintaining water requirements during pupal dormancy is particularly important because water cannot be replenished actively by drink...

  8. Getting the jump on skeletal muscle disuse atrophy: preservation of contractile performance in aestivating Cyclorana alboguttata (Gunther 1867).

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    Symonds, Beth L; James, Rob S; Franklin, Craig E

    2007-03-01

    Prolonged immobilisation or unloading of skeletal muscle causes muscle disuse atrophy, which is characterised by a reduction in muscle cross-sectional area and compromised locomotory function. Animals that enter seasonal dormancy, such as hibernators and aestivators, provide an interesting model for investigating atrophy associated with disuse. Previous research on the amphibian aestivator Cyclorana alboguttata (Günther 1867) demonstrated an absence of muscle disuse atrophy after 3 months of aestivation, as measured by gastrocnemius muscle contractile properties and locomotor performance. In this study, we aimed to investigate the effect of aestivation on iliofibularis and sartorius muscle morphology and contractile function of C. alboguttata over a longer, more ecologically relevant time-frame of 9 months. We found that whole muscle mass, muscle cross-sectional area, fibre number and proportions of fibre types remained unchanged after prolonged disuse. There was a significant reduction in iliofibularis fibre cross-sectional area (declined by 36% for oxidative fibre area and 39% for glycolytic fibre area) and sartorius fibre density (declined by 44%). Prolonged aestivation had little effect on the isometric properties of the skeletal muscle of C. alboguttata. There was a significant reduction in the isometric contraction times of the relatively slow-twitch iliofibularis muscle, suggesting that the muscle was becoming slower after 9 months of aestivation (time to peak twitch increased by 25%, time from peak twitch to half relaxation increased by 34% and time from last stimulus to half tetanus relation increased by 20%). However, the results of the work-loop analysis clearly demonstrate that, despite changes to muscle morphology and isometric kinetics, the overall contractile performance and power output levels of muscles from 9-month aestivating C. alboguttata are maintained at control levels.

  9. Transcriptional changes in epigenetic modifiers associated with gene silencing in the intestine of the sea cucumber,Apostichopus japonicus (Selenka), during aestivation

    Institute of Scientific and Technical Information of China (English)

    WANG Tianming; YANG Hongsheng; ZHAO Huan; CHEN Muyan; WANG Bing

    2011-01-01

    The sea cucumber,Apostichopusjaponicus,undergoes aestivation to improve survival during periods of high-temperature.During aestivation,the metabolic rate is depressed to reduce the consumption of reserved energy.We evaluated the role of epigenetic modification on global gene silencing during metabolic rate depression in the sea cucumber.We compared the expression of epigenetic modifiers in active and aestivating sea cucumbers.The expression of three genes involved in DNA methylation and chromatin remodeling (DNA (cytosine-5)-methyltransferase 1,Methyl-CpG-binding domain protein 2),and Chromodomain-helicase-DNA-binding protein 5) was significantly higher during aestivation (Days 20 and 40).Similarly,we observed an increase in the expression of genes involved in histone acetylation (Histone deacetylase 3) and Histone-binding protein RBBP4) during the early (Days 5 and 10) and late phases (Days 20 and 40) of aestivation.There was no change in the expression of KAT2B,a histone acetyltransferase.However,the expression of histone methylation associated modifiers (Histone-arginine methyltransferase CARMER and Histone-lysine N-methyltransferase MLL5) was significantly higher after 5 d in the aestivating group.The results suggest that the expression of epigenetic modifiers involved in DNA methylation,chromatin remodeling,histone acetylation,and histone methylation is upregulated during aestivation.We hypothesize that these changes regulate global gene silencing during aestivation in A.japonicus.

  10. Hot and steady: Elevated temperatures do not enhance muscle disuse atrophy during prolonged aestivation in the ectotherm Cyclorana alboguttata.

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    Young, K M; Cramp, R L; Franklin, C E

    2013-02-01

    Animals that undergo prolonged dormancy experience minimal muscle disuse atrophy (MDA) compared to animals subjected to artificial immobilisation over shorter timeframes. An association between oxidative stress and MDA suggests that metabolic depression presumably affords dormant animals some protection against muscle disuse. Because aerobic metabolism is temperature sensitive, we proposed that MDA in dormant (aestivating) ectotherms would be enhanced at elevated temperatures. In the green-striped burrowing frog, Cyclorana alboguttata, the thermal sensitivity of skeletal muscle metabolic rate is muscle-specific. We proposed that the degree of atrophy experienced during aestivation would correlate with the thermal sensitivity of muscle metabolic rate such that muscles with a relatively high metabolic rate at high temperatures would experience more disuse atrophy. To test this hypothesis, we examined the effect of temperature and aestivation on the extent of MDA in two functionally different muscles: the M. gastrocnemius (jumping muscle) and M. iliofibularis (non-jumping muscle), in C. alboguttata aestivating at 24 or 30 °C for 6 months. We compared a range of morphological parameters from muscle cross-sections stained with succinic dehydrogenase to show that muscle-specific patterns of disuse atrophy were consistent with the relative rates of oxygen consumption of those muscle types. However, despite muscle-specific differences in thermal sensitivity of metabolic rate, aestivation temperature did not influence the extent of atrophy in either muscle. Our results suggest that the muscles of frogs aestivating at high temperatures are defended against additional atrophy ensuring protection of muscle function during long periods of immobilisation.

  11. Synchrotron Reveals Early Triassic Odd Couple: Injured Amphibian and Aestivating Therapsid Share Burrow.

    Directory of Open Access Journals (Sweden)

    Vincent Fernandez

    Full Text Available Fossorialism is a beneficial adaptation for brooding, predator avoidance and protection from extreme climate. The abundance of fossilised burrow casts from the Early Triassic of southern Africa is viewed as a behavioural response by many tetrapods to the harsh conditions following the Permo-Triassic mass-extinction event. However, scarcity of vertebrate remains associated with these burrows leaves many ecological questions unanswered. Synchrotron scanning of a lithified burrow cast from the Early Triassic of the Karoo unveiled a unique mixed-species association: an injured temnospondyl amphibian (Broomistega that sheltered in a burrow occupied by an aestivating therapsid (Thrinaxodon. The discovery of this rare rhinesuchid represents the first occurrence in the fossil record of a temnospondyl in a burrow. The amphibian skeleton shows signs of a crushing trauma with partially healed fractures on several consecutive ribs. The presence of a relatively large intruder in what is interpreted to be a Thrinaxodon burrow implies that the therapsid tolerated the amphibian's presence. Among possible explanations for such unlikely cohabitation, Thrinaxodon aestivation is most plausible, an interpretation supported by the numerous Thrinaxodon specimens fossilised in curled-up postures. Recent advances in synchrotron imaging have enabled visualization of the contents of burrow casts, thus providing a novel tool to elucidate not only anatomy but also ecology and biology of ancient tetrapods.

  12. Increased urea synthesis and/or suppressed ammonia production in the African lungfish, Protopterus annectens, during aestivation in air or mud.

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    Loong, Ai M; Pang, Cheryl Y M; Hiong, Kum C; Wong, Wai P; Chew, Shit F; Ip, Yuen K

    2008-03-01

    The objective of this study was to elucidate how the African lungfish, Protopterus annectens, ameliorated ammonia toxicity during 12 or 46 days of aestivation in air or in mud. Twelve days of aestivation in air led to significant increases in contents of urea, but not ammonia, in tissues of P. annectens. The estimated rate of urea synthesis increased 2.7-fold despite the lack of changes in the activities of hepatic ornithine-urea cycle enzymes, but there was only a minor change in the estimated rate of ammonia production. After 46 days of aestivation in air, the ammonia content in the liver decreased significantly and contents of urea in all tissues studied increased significantly, indicating that the fish shifted to a combination of increased urea synthesis (1.4-fold of the day 0 value) and decreased ammonia production (56% of the day 0 value) to defend against ammonia toxicity. By contrast, 12 days of aestivation in mud produced only minor increases in tissue urea contents, with ammonia contents remained unchanged. This was apparently achieved through decreases in urea synthesis and ammonia production (40 and 15%, respectively, of the corresponding day 0 value). Surprisingly, 46 days of aestivation in mud resulted in no changes in tissue urea contents, indicating that profound suppressions of urea synthesis and ammonia production (2.6 and 1.2%, respectively, of the corresponding day 0 value) had occurred. This is the first report on such a phenomenon, and the reduction in ammonia production was so profound that it could be the greatest reduction known among animals. Since fish aestivated in mud had relatively low blood pO(2) and muscle ATP content, they could have been exposed to hypoxia, which induced reductions in metabolic rate and ammonia production. Consequently, fish aestivating in mud had a lower dependency on increased urea synthesis to detoxify ammonia, which is energy intensive, than fish aestivating in air.

  13. Each to their own: skeletal muscles of different function use different biochemical strategies during aestivation at high temperature.

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    Young, Karen M; Cramp, Rebecca L; Franklin, Craig E

    2013-03-15

    Preservation of muscle morphology depends on a continuing regulatory balance between molecules that protect and molecules that damage muscle structural integrity. Excessive disruption of the biochemical balance that favours reactive oxygen species (ROS) in disused muscles may lead to oxidative stress, which in turn is associated with increased atrophic or apoptotic signalling and/or oxidative damage to the muscle and thus muscle disuse atrophy. Increases in the rate of oxygen consumption likely increase the overall generation of ROS in vivo. Temperature-induced increases in oxygen consumption rate occur in some muscles of ectotherms undergoing prolonged muscular disuse during aestivation. In the green-striped burrowing frog, Cyclorana alboguttata, both large jumping and small non-jumping muscles undergo atrophy seemingly commensurate with their rate of oxygen consumption during aestivation. However, because the extent of atrophy in these muscles is not enhanced at higher temperatures, despite a temperature-sensitive rate of oxygen consumption in the jumping muscle, we proposed that muscles are protected by biochemical means that, when mobilised at higher temperatures, inhibit atrophy. We proposed that the biochemical response to temperature would be muscle-specific. We examined the effect of temperature on the antioxidant and heat shock protein systems and determined the extent of oxidative damage to lipids and proteins in two functionally different skeletal muscles, the gastrocnemius (jumping muscle) and the iliofibularis (non-jumping muscle), by aestivating frogs at 24 and 30°C for 6 months. We assayed small molecule antioxidant capacity, mitochondrial and cytosolic superoxide dismutase activities and Hsp70 concentrations to show that protective mechanisms in disused muscles are differentially regulated with respect to both temperature and aestivation. High aestivation temperature results in an antioxidant response in the metabolically temperature

  14. Aestivation induces changes in transcription and translation of coagulation factor II and fibrinogen gamma chain in the liver of the African lungfish Protopterus annectens.

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    Hiong, Kum C; Tan, Xiang R; Boo, Mel V; Wong, Wai P; Chew, Shit F; Ip, Yuen K

    2015-12-01

    This study aimed to sequence and characterize two pro-coagulant genes, coagulation factor II (f2) and fibrinogen gamma chain (fgg), from the liver of the African lungfish Protopterus annectens, and to determine their hepatic mRNA expression levels during three phases of aestivation. The protein abundance of F2 and Fgg in the liver and plasma was determined by immunoblotting. The results indicated that F2 and Fgg of P. annectens were phylogenetically closer to those of amphibians than those of teleosts. Three days of aestivation resulted in an up-regulation in the hepatic fgg mRNA expression level, while 6 days of aestivation led to a significant increase (3-fold) in the protein abundance of Fgg in the plasma. Hence, there could be an increase in the blood-clotting ability in P. annectens during the induction phase of aestivation. By contrast, the blood-clotting ability in P. annectens might be reduced in response to decreased blood flow and increased possibility of thrombosis during the maintenance phase of aestivation, as 6 months of aestivation led to significant decreases in mRNA expression levels of f2 and fgg in the liver. There could also be a decrease in the export of F2 and Fgg from the liver to the plasma so as to avert thrombosis. Three to 6 days after arousal from 6 months of aestivation, the protein abundance of F2 and Fgg recovered partially in the plasma of P. annectens; a complete recovery of the transcription and translation of f2/F2 in the liver might occur only after refeeding.

  15. Activity, abundance and expression of Ca²⁺-activated proteases in skeletal muscle of the aestivating frog, Cyclorana alboguttata.

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    Reilly, Beau D; Cramp, Rebecca L; Franklin, Craig E

    2015-02-01

    In most mammals, prolonged muscle disuse (e.g. bed-rest, limb casting or spaceflight) results in atrophy of muscle fibres which is largely due to unregulated proteolysis. Although numerous proteolytic pathways are known to participate in muscle disuse atrophy, recent evidence suggests that activation of Ca²⁺-dependent cysteine proteases (calpains) is required for disuse atrophy in limb skeletal muscles. In contrast to typical models of muscle disuse (humans and rodents), animals that experience natural bouts of chronic muscle inactivity, such as hibernating mammals and aestivating frogs, consistently exhibit limited or no change in skeletal muscle size. In the current study, we examined enzyme activity, protein abundance and gene expression levels of calpain isoforms in gastrocnemius muscle of the aestivating frog, Cyclorana alboguttata. We predicted that in aestivating C. alboguttata there would be a downregulation of the abundance, activity and gene expression of calpain 1 and calpain 2. In contrast to our hypothesis, there was no significant decrease in the enzyme activity levels or the relative protein abundances of calpain 1 and calpain 2. Similarly, gene expression assays (both qRT-PCR and RNA Seq data) indicated that calpains were unaffected by aestivation. Western blotting of 'muscle-specific' calpain 3, which is consistently downregulated during atrophic conditions, indicated that this isoform is present in C. alboguttata muscle where it appears to be in its autolysed state. The absence of any increase in enzyme activity, protein and mRNA abundance of calpains in aestivators is consistent with the protection of gastrocnemius muscle against uncontrolled proteolysis throughout aestivation.

  16. Aestivation Induces Changes in the mRNA Expression Levels and Protein Abundance of Two Isoforms of Urea Transporters in the Gills of the African Lungfish, Protopterus annectens

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    Chng, You R.; Ong, Jasmine L. Y.; Ching, Biyun; Chen, Xiu L.; Hiong, Kum C.; Wong, Wai P.; Chew, Shit F.; Lam, Siew H.; Ip, Yuen K.

    2017-01-01

    The African lungfish, Protopterus annectens, is ammonotelic in water despite being ureogenic. When it aestivates in mucus cocoon on land, ammonia is detoxified to urea. During the maintenance phase of aestivation, urea accumulates in the body, which is subsequently excreted upon arousal. Urea excretion involves urea transporters (UT/Ut). This study aimed to clone and sequence the ut isoforms from the gills of P. annectens, and to test the hypothesis that the mRNA and/or protein expression levels of ut/Ut isoforms could vary in the gills of P. annectens during the induction, maintenance, and arousal phases of aestivation. Two isoforms of ut, ut-a2a and ut-a2b, were obtained from the gills of P. annectens. ut-a2a consisted of 1227 bp and coded for 408 amino acids with an estimated molecular mass of 44.7 kDa, while ut-a2b consisted of 1392 bp and coded for 464 amino acids with an estimated molecular mass of 51.2 kDa. Ut-a2a and Ut-a2b of P. annectens had a closer phylogenetic relationship with Ut/UT of tetrapods than Ut of fishes. While the mRNA expression pattern of ut-a2a and ut-a2b across various tissues of P. annectens differed, the transcript levels of ut-a2a and ut-a2b in the gills were comparable, indicating that they might be equally important for branchial urea excretion during the initial arousal phase of aestivation. During the maintenance phase of aestivation, the transcript level of ut-a2a increased significantly, but the protein abundance of Ut-a2a remained unchanged in the gills of P. annectens. This could be an adaptive feature to prepare for an increase in the production of Ut-a2a upon arousal. Indeed, arousal led to a significant increase in the branchial Ut-a2a protein abundance. Although the transcript level of ut-a2b remained unchanged, there were significant increases in the protein abundance of Ut-a2b in the gills of P. annectens throughout the three phases of aestivation. The increase in the protein abundance of Ut-a2b during the maintenance

  17. Effect of water temperature on digestive enzyme activity and gut mass in sea cucumber Apostichopus japonicus (Selenka), with special reference to aestivation

    Institute of Scientific and Technical Information of China (English)

    GAO Fei; YANG Hongsheng; XU Qiang; WANG Fangyu; LIU Guangbin

    2009-01-01

    The effect of water temperature on gut mass and digestive enzyme activity in sea cucumber Apostichopus japonicus, including relative gut mass (RGM), amylase, lipase, pepsin and trypsin activities were studied at temperatures of 7, 14, 21, and 28°C over a period of 40 days. Results show that RGM significantly decreased after 40 days at 21°C and markedly decreased over the whole experiment period at 28°C; however, no significant effect of duration was observed at 7 or 14°C. At 14°C, trypsin activity significantly decreased over 10 and 20 days, then increased; amylase and trypsin activity significantly decreased after 40 days at 28°C. However, no significant effect of duration was found on amylase, pepsin or trypsin activities in the other temperature treatment groups. At 28°C, lipase activity peaked in 20 days and then markedly decreased to a minimum at the end of the experiment. On the other hand, pepsin activity at 28°C continuously increased over the whole experimental period. Principle component analysis showed that sea cucumbers on day 40 in the 21°C group and in the previous 20 days in the 28°C group were in the prophase of aestivation. At 28°C, sea cucumbers aestivated at 30-40 days after the start of the experiment. It is concluded that the effect of temperature on the digestion of A. japonicus is comparatively weak within a specific range of water temperatures and aestivation behavior is accompanied by significant changes in RGM and digestive enzyme activities.

  18. Snails in the desert: Assessing the mitochondrial and morphological diversity and the influence of aestivation behavior on lineage differentiation in the Australian endemic Granulomelon Iredale, 1933 (Stylommatophora: Camaenidae).

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    Criscione, Francesco; Köhler, Frank

    2016-01-01

    Progressive aridification since the mid-Miocene has had a significant influence on the evolution of the biota in the arid zone of central Australia. Especially moisture sensitive groups, such as snails, are often restricted to topographically complex areas, which have acted as refugia in an otherwise inhospitable environment. This historical fragmentation is deemed to be a potent agent of allopatric lineage diversification. Camaenid land snails are amongst only a few terrestrial gastropods that have managed to survive in the arid zone probably due to their ability to escape desiccation through aestivation. Here, we present the first study of the mitochondrial lineage differentiation in an endemic land snail genus from the Australian 'Red Centre', Granulomelon Iredale, 1933. Exposing significant incongruence between mtDNA phylogeny and morphology-based taxonomy, we completely revise the species and genus level taxonomy of this camaenid group. We demonstrate that this genus contains three species, G. grandituberculatum, G. adcockianum and G. squamulosum, which have so far been assigned to different genera: Granulomelon Iredale, 1933 (junior synonym: Baccalena Iredale, 1937), Basedowena Iredale, 1937 and Pleuroxia Ancey, 1887. Two of these species are widespread comprising multiple divergent mitochondrial lineages. Based on a molecular clock estimate, these lineages diverged approximately during the mid-Pleistocene, a period of particularly severe aridification. The phylogeographic patterns are consistent with an isolation-by-distance model in one species but not the other. We suggest that these differences can be attributed to their distinctive aestivation behavior.

  19. Research on aestivation and its modulation via industrialized farming of sea cucumber Apostichopus japonicus—A review%刺参夏眠及其工厂化养殖调控技术

    Institute of Scientific and Technical Information of China (English)

    陈世波; 刘慧; 朱建新

    2013-01-01

    夏眠是刺参重要的生态习性,夏眠期间刺参停止摄食,肠道退化、萎缩,生长停滞,因而刺参夏眠是影响刺参养殖产量和效益的关键因素之一.在刺参养殖中,如何解决刺参夏眠所引起的摄食停止、体重减轻问题,提高刺参养殖效率和效益,是一个重要的科学和技术难题.文中归纳总结了对人工养殖刺参的夏眠时间、夏眠临界温度、夏眠诱因及刺参夏眠期间主要生理指标变化等方面的研究成果,借此探讨通过养殖环境调控来减少或消除刺参夏眠的理论依据和可行性;介绍了刺参工厂化养殖中人工控温、控光、水质调节、营养调节和养殖管理技术,列举了几家工厂化养殖剌参案例,并指出了刺参工厂化养殖未来研究方向.%Aestivation is an important ecological characteristic of sea cucumber Apostichopus japonicus.The animals stop feeding and aestivate at high temperatures in summer,resulting in serious tissue regression,metabolic rate depression and growth suspension.It is a major challenge in science and technology to improve the growth performance of sea cucumbers during the warmer season,so as to increase the efficiency and benefit of its aquaculture.In this article,research on aestivation of A.japonicus is reviewed,including the time period,threshold temperature and incentives for aestivation,and major physiological change of the animal during aestivation.The theoretical basis and possibility for aestivation "alleviation" or reduction via control of environmental conditions is also discussed.Furthermore,management measures for industrialized sea cucumber culture,such as temperature,light and water quality control,as well as nutrition manipulation is introduced,along with the practice of a number of commercialized farms in China.Future research on industrialized sea cucumber farming is suggested.

  20. Constitutional Analysis of Aestival Air Conditioning Load of the Residential Building Envelop in the Yangtze Valley%长江流域住宅夏季空调围护结构负荷构成分析

    Institute of Scientific and Technical Information of China (English)

    张小波; 张旭; 王健

    2011-01-01

    The aestival air conditioning load of the residential building envelops is affected by their own geometric and thermal parameters in the Yangtze Valley; however their influence factors are still unclear. This Paper mainly considers the parameters such as heat transfer coefficients of building envelops, area ratio of window to wall and shading coefficient. In virtue of the princi-ple of orthogonal test, it calculates and analyzes the aestival air conditioning load of the southern building envelops in the design situation, so as to determine the main influence parameters. For the southern aspect, the unit area load linearly increases with all the parameters. Among them, the area ratio of window to wall is the most important one, when it is greater, shading coefficient and heat transfer coefficient of the window have more dramatic effect, otherwise heat transfer coefficient of the wall do. By dint of the correlations of the wall-envelop load ratio and unit area load with the parameters, the energy saving potentials can be deter-mined and effective suggestions are provided for the energy saving measures for the building envelops in this area.%长江流域住宅夏季空调围护结构负荷受其自身几何和热工参数的影响,但是各参数的影响程度还不明确.本文主要考虑围护结构传热系数、窗墙比和遮阳系数等参数,利用正交试验的原理计算分析夏季空调设计工况下南侧围护结构负荷构成,以确定主要影响参数.对于南侧外围护结构,单位面积负荷与各参数均成正线性相关,其中窗墙比的影响最大.当窗墙比较大时,遮阳系数和外窗传热系数的影响较大,反之外墙传热系数影响较大.利用单位面积负荷及外墙负荷比与参数之间的关系式可以分析确定该地区围护结构节能的潜力,并为确定有效的围护结构节能措施提供依据.

  1. 东江支流夏季小型浮游动物群落特征研究%Aestival Characteristics of Small Zooplankton Communities in the Main Tributaries of the Dongjiang River

    Institute of Scientific and Technical Information of China (English)

    彭秋志; 廖剑宇; 伍凯; 刘全儒; 周云龙; 江源; 龚玲

    2013-01-01

    Our goal was to describe the aestival features of small zooplankton communities in the main tributaries of the Dongjiang River and test the possibility of using prominent features derived from the zooplankton community as predictive indicators of water quality. By systematically selecting representative tributaries of the Dongjiang River as case study sites, we randomly sampled small zooplankton (Protozoa and Rotifers) communities along the tributaries in My 2010. The species composition of those zooplankton communities was identified to the genus level, and indices including richness, density, relative density, frequency and diversity were counted. Environmental variables including temperature, dissolved oxygen, electrical conductivity, total phosphorus, total nitrogen, ammonia nitrogen, nitrate nitrogen, permanganate index, and chlorophyll a were also measured. We identified 36 genera, of which 23 belonged to Protozoa and 13 to Rotifers. Those taxa in most cases emerged in low density and low richness in samples. Within a sample, however, often one of the genera was found at a relatively high density, while fewer genera dominated the density and frequency. This implied that small river channels are not suitable for zooplankton growth, whereas diversified habitats resulted in a variety of community composition types. An increased trend from up- to down-stream was found in density, richness and diversity, while at the same time a decreased trend in dominance occurred. Many factors, such as zooplankton origins, available nutrients and flow velocity, could all be influencing the small zooplankton community. Significant correlations between the density of certain special genera and most environmental variables were found, indicating that density might be used as the zooplankton indicator in assessing and monitoring river environmental conditions. On the contrary, the diversity of zooplankton should not be used as a competent indicator in assessment, since there was no

  2. Analysis of fatty acid composition of sea cucumber Apostichopus japonicus using multivariate statistics

    Science.gov (United States)

    Xu, Qinzeng; Gao, Fei; Xu, Qiang; Yang, Hongsheng

    2014-11-01

    Fatty acids (FAs) provide energy and also can be used to trace trophic relationships among organisms. Sea cucumber Apostichopus japonicus goes into a state of aestivation during warm summer months. We examined fatty acid profiles in aestivated and non-aestivated A. japonicus using multivariate analyses (PERMANOVA, MDS, ANOSIM, and SIMPER). The results indicate that the fatty acid profiles of aestivated and non-aestivated sea cucumbers differed significantly. The FAs that were produced by bacteria and brown kelp contributed the most to the differences in the fatty acid composition of aestivated and nonaestivated sea cucumbers. Aestivated sea cucumbers may synthesize FAs from heterotrophic bacteria during early aestivation, and long chain FAs such as eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) that produced from intestinal degradation, are digested during deep aestivation. Specific changes in the fatty acid composition of A. japonicus during aestivation needs more detailed study in the future.

  3. Ecological and physiological aspects of aestivation-diapause in the larvae of twe pyralid stalk borers of maize in Kenya

    NARCIS (Netherlands)

    Scheltes, P.

    1978-01-01

    Stalk borers are highly destructive to a large number of important graminaceous crops all over the world. Some examples of economically important stalk borers and a general description of their life-cycle are mentioned in chapter 1. In the same chapter difficulties in controlling the insects are des

  4. 刺参夏眠的研究进展%Research advances in aestivation of sea cucumber Apostichopus japonicus (Selenka): a review

    Institute of Scientific and Technical Information of China (English)

    袁秀堂; 杨红生; 陈慕雁; 高菲

    2007-01-01

    刺参(Apostichopus japonicus(Selenka)),又称仿刺参,属棘皮动物门(Echinodermata),海参纲(Holothuroidea),主要分布于北纬35°到44°的广大西北太平洋沿岸,北起俄罗斯的海参威,经日本海、朝鲜半岛南部到中国黄、渤海。据报道,江苏连云港外的平山岛是该物种在中国分布的最南界。刺参是典型的温带种类,在其生活史中存在着一种重要的生态习性:当夏季海水温度升高到一定范围后,

  5. Growth, Metabolism and Physiological Response of the Sea Cucumber, Apostichopus japonicus Selenka During Periods of Inactivity

    Institute of Scientific and Technical Information of China (English)

    DU Rongbin; ZANG Yuanqi; TIAN Xiangli; DONG Shuanglin

    2013-01-01

    The growth,metabolism and physiological response of the sea cucumber,Apostichopus japonicus,were investigated during periods of inactivity.The body weight,oxygen consumption rate (OCR),activities of acidic phosphatase (ACP),alkaline phosphatase (AKP),catalase (CAT) and superoxide dismutase (SOD),and content of heat shock protein 70 (Hsp70) in the body wall and coelomic fluid of A.japonicus were measured during starvation,experimental aestivation and aestivation.The results showed that the body weight of sea cucumber in the three treatments decreased significantly during the experimental period (P<0.05).The OCR of sea cucumber reduced in starvation and experimental aestivation treatments,but increased gradually in natural aestivation treatment.The activities of ACP and AKP of sea cucumber decreased gradually in all treatments,whereas those of SOD and CAT as well as Hsp70 content decreased in the starvation and experimental aestivation treatments and increased in natural aestivation treatment.The sea cucumber entered a state of aestivation at 24℃.To some extent,the animals in experimental aestivation were different from those in natural aestivation in metabolism and physiological response.These findings suggested that the aestivation mechanism ofA.japonicus is complex and may not be attributed to the elevated temperature only.

  6. 夏眠对刺参(Apostichopus japonicus (Selenka))能量收支的影响%Effects of aestivation on energy budget of sea cucumber Apostichopus japonicus(Selenka)(Echinodermata: Holothuroidea)

    Institute of Scientific and Technical Information of China (English)

    袁秀堂; 杨红生; 王丽丽; 周毅; 张涛; 刘鹰

    2007-01-01

    夏眠是刺参最重要的生理特征;水温升高是其夏眠的主要诱发因子,而夏眠的临界温度与刺参体重密切相关.为揭示刺参夏眠对其能量利用对策的影响,测定了2种体重规格(134.0±13.5)g和(73.6±2.2)g刺参在10、15、20、25 ℃和30 ℃ 5个温度梯度下的能量收支.结果表明,温度和体重及其交互作用对刺参能量的摄入均有显著影响;而温度是影响其摄食能分配的主要因素.研究发现,刺参在非夏眠期、夏眠临界期和完全夏眠期的能量利用对策有所不同:在非夏眠期,刺参摄食能支出的最大组分是粪便能,占摄食能的比例超过50%,其次为呼吸耗能,占19.8%~39.4%,而生长能和排泄能占的比例较小,分别为5.7%~10.7%和2.9%~3.7%;在夏眠临界温度下,呼吸和排泄耗能占摄食能的比例均显著增大(分别为88.3%和13.6%),而生长能所占比例降为负值(-55.3%),刺参表现为负生长;而在夏眠期,刺参的摄食能和排粪能为零,为维持其基本生理活动,不得不动用以往贮存于体内的能量,消耗于呼吸和排泄等生理过程,供维持生命之用.总之,从能量生物学的角度看,夏眠的主要生态学意义在于刺参长时间处于相对高温环境,进而导致摄食受阻条件下的一种能量节约方式.

  7. Controlling Townsend Ground Squirrels in Beaver County, Utah

    OpenAIRE

    Nelson, Mark

    2012-01-01

    Townsend ground squirrels live in colonies and construct underground burrows that have a number of entrances. The burrows may be up to 6 feet deep. The squirrels generally enter their burrows to aestivate, escaping the late summer heat

  8. Decreased hydrogen peroxide production and mitochondrial respiration in skeletal muscle but not cardiac muscle of the green-striped burrowing frog, a natural model of muscle disuse.

    Science.gov (United States)

    Reilly, Beau D; Hickey, Anthony J R; Cramp, Rebecca L; Franklin, Craig E

    2014-04-01

    Suppression of disuse-induced muscle atrophy has been associated with altered mitochondrial reactive oxygen species (ROS) production in mammals. However, despite extended hindlimb immobility, aestivating animals exhibit little skeletal muscle atrophy compared with artificially immobilised mammalian models. Therefore, we studied mitochondrial respiration and ROS (H2O2) production in permeabilised muscle fibres of the green-striped burrowing frog, Cyclorana alboguttata. Mitochondrial respiration within saponin-permeabilised skeletal and cardiac muscle fibres was measured concurrently with ROS production using high-resolution respirometry coupled to custom-made fluorometers. After 4 months of aestivation, C. alboguttata had significantly depressed whole-body metabolism by ~70% relative to control (active) frogs, and mitochondrial respiration in saponin-permeabilised skeletal muscle fibres decreased by almost 50% both in the absence of ADP and during oxidative phosphorylation. Mitochondrial ROS production showed up to an 88% depression in aestivating skeletal muscle when malate, succinate and pyruvate were present at concentrations likely to reflect those in vivo. The percentage ROS released per O2 molecule consumed was also ~94% less at these concentrations, indicating an intrinsic difference in ROS production capacities during aestivation. We also examined mitochondrial respiration and ROS production in permeabilised cardiac muscle fibres and found that aestivating frogs maintained respiratory flux and ROS production at control levels. These results show that aestivating C. alboguttata has the capacity to independently regulate mitochondrial function in skeletal and cardiac muscles. Furthermore, this work indicates that ROS production can be suppressed in the disused skeletal muscle of aestivating frogs, which may in turn protect against potential oxidative damage and preserve skeletal muscle structure during aestivation and following arousal.

  9. Eco-physiological adaptation of the land snail Achatina achatina (Gastropoda: Pulmonata in tropical agro-ecosystem

    Directory of Open Access Journals (Sweden)

    Christian O. Chukwuka

    2014-03-01

    Full Text Available The survival of land snails in an adverse environmental condition depends on the integral physiological, morphological and behavioural adaptations. These adaptations are essential in understanding the species-specific habitat requirements and in predicting their environmental responses. In this study, the monthly and the periodic patterns of eco-physiological adaptation of land snail, Achatina achatina in Nsukka tropical agro-ecosystem were assessed from December 2012 to July 2013. Standard methods were employed in sampling the land snail and determination of the water content, biochemical fuel reserves and enzyme concentrations of the samples. The present results showed that lipids were high at the beginning of aestivation and depleted as the aestivation progressed. Glycogen was significantly low throughout the aestivation months (December–March and increased in the active months (April–July. Protein content recorded a definite pattern all through the months studied. Catabolism of lactate and a decrease in activity of LDH during aestivation and substantial increase upon activation were observed. Data showed that transaminase and aspartate enzymes depleted during the aestivation months indicating that the snails may have developed potential cell injury due to oxidative stress and thermal heat. A disassociation between the physiological responses and climatic data was recorded. The physiological adaptation of A. achatina ensures regular adjustment under extreme conditions and compensates for its metabolic regulation in the tropics. It is concluded that survival of A. achatina is not environmentally predicted; rather it depends on the species-specific inherent process in predicting responses for survival.

  10. Role of calcium and vesicle-docking proteins in remobilising dormant neuromuscular junctions in desert frogs.

    Science.gov (United States)

    Lavidis, Nickolas A; Hudson, Nicholas J; Choy, Peng T; Lehnert, Sigrid A; Franklin, Craig E

    2008-01-01

    Despite prolonged immobility the desert frog, Cyclorana alboguttata, suffers little impairment in muscle function. To determine compensatory mechanisms at neuromuscular junctions, transmitter release was examined along primary terminals in C. alboguttata iliofibularis muscle. Using extracellular recording we found the amplitudes of evoked endplate currents were significantly smaller in dormant frogs. In active frogs we identified two negatively sloping proximal-distal gradients of transmitter frequency and quantal content; a shallow proximal-distal gradient with low probability of transmitter release (0.6). During aestivation, only a shallow gradient was identified. The high probability release sites in control frogs were inhibited during aestivation by a mechanism that could be reversed by (1) increasing the extracellular calcium concentration, and (2) increasing the frequency of stimulation. This suggests that transmitter vesicles are available during aestivation but not released. We quantified expression of messenger RNA transcripts coding for the transmitter vesicle-docking proteins synaptotagmin 1, syntaxin 1B and UNC-13. All three were rare transcripts maintained at control values during aestivation. Neuromuscular remobilisation after dormancy in C. alboguttata is more likely a product of rapidly reversible physiologic mechanisms than reorganisations of the neuromuscular transcriptome.

  11. AcEST: DK948737 [AcEST

    Lifescience Database Archive (English)

    Full Text Available m aestiv... 197 1e-61 tr|A9RMR0|A9RMR0_PHYPA Predicted protein OS=Physcomitrella paten... 195 2e-61 tr|Q4PSE8|Q4PS...18 VSGGGQSEDKKVSYGFSSLRGKRASMEDFLDAQISQVDGVTVGLFGVFD 66 >tr|Q4PSE8|Q4PSE8_ARATH Putative uncharacterized pro

  12. Differential expression of aquaporin 3 in Triturus italicus from larval to adult epidermal conversion

    Directory of Open Access Journals (Sweden)

    E Brunelli

    2009-06-01

    Full Text Available By using immunohistochemical techniques applied to confocal microscopy, the presence of aquaporin 3 water channel in the epidermis of Triturus italicus (Amphibia, Urodela has been shown. We analysed the expression of aquaporin 3 (AQP3 during the larval, pre-metamorphic and adult phases; we also showed the localization of the water-channel protein AQP3 in free-swimming conditions and during aestivation in parallel with histological analysis of the skin, focusing on the possible relationship between protein expression and terrestrial habitats. Our results indicate that aquaporin is produced as the epidermis modifies during the functional maturation phase starting at the climax. Moreover, our data suggest an increase in enzyme expression in aestivating newts emphasizing the putative functional importance of differential expression related to a distinct phase of the biological cycle.

  13. La casside de la betterave (Cassida vittata Wild, Col., Chrysomelidae au Gharb: cycle de développement et stratégie de lutte

    Directory of Open Access Journals (Sweden)

    M'Hamed HMIMINA

    2015-12-01

    Full Text Available In the Gharb and Loukkos regions, the Tortoise Beetle (Cassida vittata Vill develops a single annual generation due to obligatory imaginal dormancy induced by summer conditions. The weekly counts of the various stages of the insect made during two campaigns, reveal a homogeneous life cycle for all areas covered by the study: arrival of adults on fields of sugar beet from early January, feeding and spawning starting from late February to early March, straddling larval development, adult of the year generation and migration to sites of aestivation. The influence of these sites of aestivating on the infestation of adjacent beet crops has been sought. Depending on the method of analysis used, it seems not to be clear correlation. At their awakening, the Tortoise Beetle likely scatter freely on the fields.

  14. Morfologia y biologia de Bostryx conspersus (Sowerby (Mollusca, Bulimulidae en las lomas costeras del Peru Central

    Directory of Open Access Journals (Sweden)

    Rina Ramírez

    1988-01-01

    Full Text Available Morphological and biological observations on populations of the land snail Bostryx conspersus, in three "Lomas"of the Central Coast of Peru, were carried out between 1979 and 1982. Three shell color varieties of B. conspersus are reponed herein, as well as its aestivation, activity and reproduction strategies. The possible interactions of B. conspersus with a dipteron (Scaptomyza sp.; Drosophilidae and a nematode species are also discussed.

  15. Short-term changes in Ca, Pb, Zn and Cd concentrations of the garden snail Helix aspersa Muller from a central London car park

    Energy Technology Data Exchange (ETDEWEB)

    Beeby, A.; Eaves, S.L.

    1983-03-01

    Helix aspersa were collected from a car park with a high degree of Pb and Zn pollution over a period of 102 days following the end of aestivation. Analysis of whole soft tissues demonstrates a high variability in both Pb and Ca levels in the short term, possibly associated with shell formation. Pb, Zn and Ca concentrations are also shown to vary with age-class. No simple relationship between total Ca and total heavy metal levels was found, and it is concluded that Ca does not account for the high variability between individuals. The rate of loss of each metal is shown to vary with age-class.

  16. Dicty_cDB: Contig-U05027-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available l20d05, 3' end. 38 0.007 3 ( EE992460 ) Le_emtis_408F14_M13R29 Little skate (Leucoraja... er... 54 0.008 1 ( EE990892 ) Le_emtis_302G03_M13R29 Little skate (Leucoraja er... 54 0.008 1 ( DR7835... 1 ( FF600506 ) Le_emcl1_01B02_M13Reverse Little Skate (Leucoraja... 54 0.008 1 ( CJ553077 ) Triticum aestiv

  17. Observations of cocooned Hydrobaenus (Diptera: Chironomidae) larvae in Lake Michigan

    Science.gov (United States)

    Tucker, Taaja R.; Hudson, Patrick L.; Riley, Stephen

    2016-01-01

    Larvae of the family Chironomidae have developed a variety of ways to tolerate environmental stress, including the formation of cocoons, which allows larvae to avoid unfavorable temperature conditions, drought, or competition with other chironomids. Summer cocoon formation by younger instars of the genus Hydrobaenus Fries allows persistence through increased temperatures and/or intermittent dry periods in arid regions or temporary habitats, but this behavior was not observed in the Great Lakes until the current study. Cocoon-aestivating Hydrobaenus sp. larvae were found in benthic grab samples collected in 2010–2013 near Sleeping Bear Dunes National Lakeshore in northern Lake Michigan with densities up to 7329/m2. The aestivating species was identified as Hydrobaenus johannseni (Sublette, 1967), and the associated chironomid community was typical for an oligotrophic nearshore system. Hydrobaenus cocoon formation in the Great Lakes was likely previously unnoticed due to the discrepancies between the genus' life history and typical benthos sampling procedures which has consequences for describing chironomid communities where Hydrobaenus is present.

  18. Heat shock proteins and survival strategies in congeneric land snails (Sphincterochila) from different habitats.

    Science.gov (United States)

    Mizrahi, Tal; Heller, Joseph; Goldenberg, Shoshana; Arad, Zeev

    2012-09-01

    Polmunate land snails are subject to stress conditions in their terrestrial habitat, and depend on a range of behavioural, physiological and biochemical adaptations for coping with problems of maintaining water, ionic and thermal balance. The involvement of the heat shock protein (HSP) machinery in land snails was demonstrated following short-term experimental aestivation and heat stress, suggesting that land snails use HSPs as part of their survival strategy. As climatic variation was found to be associated with HSP expression, we tested whether adaptation of land snails to different habitats affects HSP expression in two closely related Sphincterochila snail species, a desert species Sphincterochila zonata and a Mediterranean-type species Sphincterochila cariosa. Our study suggests that Sphincterochila species use HSPs as part of their survival strategy following desiccation and heat stress, and as part of the natural annual cycle of activity and aestivation. Our studies also indicate that adaptation to different habitats results in the development of distinct strategies of HSP expression in response to stress, namely the reduced expression of HSPs in the desert-inhabiting species. We suggest that these different strategies reflect the difference in heat and aridity encountered in the natural habitats, and that the desert species S. zonata relies on mechanisms and adaptations other than HSP induction thus avoiding the fitness consequences of continuous HSP upregulation.

  19. Considerações taxonômicas e novas combinações em Ardisia Swartz (Myrsinaceae do sudeste do Brasil Taxonomic considerations and new combinations in Ardisia Swartz (Myrsinaceae from Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Luís Carlos Bernacci

    2000-12-01

    Full Text Available Os tipos de placentação e de pré-floração têm sido utilizados para a distinção dos gêneros Ardisia Swartz, ao qual tem sido atribuído placentação plurisseriada e pré-floração imbricada ou quincuncial, e Stylogyne A.DC., ao qual tem sido atribuído placentação unisseriada e pré-floração contorta. Entretanto, a análise de dez espécies destes gêneros revelou a inconsistência destes caracteres. Também foi constatada a impossibilidade de observar diferenças no tipo de placentação em espécimes com poucos óvulos. Propõe-se, portanto, o restabelecimento da circunscrição de Ardisia, incluindo o gênero Stylogyne, conforme adotado por Miquel, em 1856 e Handro, em 1969. Desta forma, Ardisia ambigua Mart. é o nome válido para S. ambigua (Mart. Mez e Ardisia martiana Miq. o é para S. laevigata (Mart. Mez. Duas novas combinações são necessárias: Ardisia depauperata (Mez Bernacci & Jung-Mendaçolli e Ardisia warmingii (Mez Bernacci & Jung-Mendaçolli.Placentation and aestivation have traditionally been used as diagnostic features to separate the genera Ardisia Swartz and Stylogyne A.DC. While Ardisia has pluriseriate placentation and imbricate or quincuncial aestivation, Stylogyne has uniseriate placentation and contorted aestivation. However, careful examination of ten species of these genera revealed the inconsistency of these characters in the distinction of the two genera. Also, we noticed the impossibility of observation of placentation types in few-ovuled specimens. Therefore, we propose the re-establishment of the circumscription of Ardisia adopted by Miquel, in 1856, and Handro, in 1969 which includes the genus Stylogyne. In this way Ardisia ambigua Mart. is the valid name for S. ambigua (Mart. Mez as Ardisia martiana Miq. is for S. laevigata (Mart. Mez. Two new combinations are necessary: Ardisia depauperata (Mez Bernacci & Jung-Mendaçolli and Ardisia warmingii (Mez Bernacci & Jung-Mendaçolli.

  20. Development of dismantling and sodium removal technique for large sodium components

    Energy Technology Data Exchange (ETDEWEB)

    Hirakawa, Yasushi; Nakai, Satoru [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    2002-06-01

    Large sodium test facilities that had been constructed to perform R and D for Monju were dismantled after the removal of sodium. Because experience of such tasks in limited, for the establishment of the technology, information on past experiences, R and D results, the results of small-scale sodium removal experiments and related information were gathered worldwide. Different sodium removal processes such as the alcohol process, water vapor nitrogen process, aestivation process etc. were selected based on the component structure and were applied to various components such as the steam generator, cold trap, intermediate heat exchanger etc. As a result, sodium removal and dismantling of these facilities were conducted successfully without sodium fires, injuries caused by sodium and with little burden to the environment. Furthermore, problems to be solved when applying these processes to the radioactive sodium components were identified and an R and D plan was drawn up. (author)

  1. Pathogenicity of the entomopathogenic fungus Metarhizium anisopliae var. major on different stages of the sunn pest Eurygaster integriceps.

    Science.gov (United States)

    Sedighi, Neda; Abbasipour, Habib; Askary, Hassan; Gorjan, Aziz Sheikhi; Karimi, Jaber

    2013-01-01

    The sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is the most important insect pest of wheat and barley. The population management of this pest is of major concern to wheat producers. One of the potential control strategies is to use entomopathogenic fungi. This study evaluates the pathogenicity of the fungus Metarhizium anisopliae var. major (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) on the sunn pest, E. integriceps. Five concentrations of the fungus were utilized, ranging from 1×10(4) to 1×10(8) conidia/mL, accompanied by controls. Fifth instar nymphs and adults (a migratory summer population and a diapausing population) previously exposed to fungi were sown to isolate the fungi, and the growth parameters were analyzed. A direct spray technique was used to expose the isolates to the E. integriceps. The experiment was repeated four times, and mortalities of the insects for all treatments were recorded daily. The results showed that the mortality of infected nymphs was significantly higher than the mortality of control nymphs. Also, the longevity of infected adults was lower than the controls. The results also showed that diapausing adults of the sunn pest were much more susceptible to infection than the summer adults. Estimated LC50 values for the M14 isolate were 1.4 × 10(6), 1.4 ×10 (5) , and 2.3 × 10(3) spores/mL against the aestivation population, the diapausing population, and 5(th) instar nymphs, respectively. Estimated LT50 values using 10(8) spores/mL of the Mm isolate on the aestivation and diapausing populations were 11.9 and 5.11 days, respectively. The results demonstrated that M. anisoplaie was effective on all of stages of E. integriceps. In addition, the nymphal stage was more susceptible than the adults.

  2. The Australian Bogong moth Agrotis infusa: A long-distance nocturnal navigator

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    Eric eWarrant

    2016-04-01

    Full Text Available The nocturnal Bogong moth (Agrotis infusa is an iconic and well-known Australian insect that is also a remarkable nocturnal navigator. Like the Monarch butterflies of North America, Bogong moths make a yearly migration over enormous distances, from southern Queensland, western and northwestern New South Wales (NSW and western Victoria, to the alpine regions of NSW and Victoria. After emerging from their pupae in early spring, adult Bogong moths embark on a long nocturnal journey towards the Australian Alps, a journey that can take many days or even weeks and cover over 1000 km. Once in the Alps (from the end of September, Bogong moths seek out the shelter of selected and isolated high ridge-top caves and rock crevices (typically at elevations above 1800 m. In hundreds of thousands, moths line the interior walls of these cool alpine caves where they hibernate over the summer months (referred to as aestivation. Towards the end of the summer (February and March, the same individuals that arrived months earlier leave the caves and begin their long return trip to their breeding grounds. Once there, moths mate, lay eggs and die. The moths that hatch in the following spring then repeat the migratory cycle afresh. Despite having had no previous experience of the migratory route, these moths find their way to the Alps and locate their aestivation caves that are dotted along the high alpine ridges of southeastern Australia. How naïve moths manage this remarkable migratory feat still remains a mystery, although there are many potential sensory cues along the migratory route that moths might rely on during their journey, including visual, olfactory, mechanical and magnetic cues. Here we review our current knowledge of the Bogong moth, including its natural history, its ecology, its cultural importance to the Australian Aborigines and what we understand about the sensory basis of its long-distance nocturnal migration. From this analysis it becomes clear

  3. Habitat use, daily activity periods, and thermal ecology of Ameiva ameiva (Squamata: Teiidae in a caatinga area of northeastern Brazil

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    Eliza M. X. Freire

    2011-12-01

    Full Text Available We studied the use of spatial, temporal, and thermal resources by the Neotropical lizard Ameiva ameiva during rainy and dry seasons in a caatinga (xerophilous open forests environment in northeasternBrazil. Lizards used the vegetation habitats and microhabitats in the ground, but never were seen in the rocky habitat. Adults usually used the arboreal-shrubby habitat, whereas juveniles were sighted more often in the shrubby-herbaceous habitat. Ontogenetic differences in spatial use seem to be linked to different thermal needs between age groups owing to differences in body size. Body temperatures were significantly higher in juveniles than in adults. Most teiid species have elevated body temperatures, usually above 37oC, and are active during the hottest times of day, as was observed for A. ameiva in this study. Seasonality influenced habitat use and daily activity periods of adults, but not body temperatures. We verified annual fluctuations in adult abundance, with a decline of active lizards in the dry season; this phenomenon may be related to aestivation and/or increased mortality rate during the driest months.

  4. Ecology of Anopheles dthali Patton in Bandar Abbas District, Hormozgan Province, Southern Iran

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    H Vatandoost

    2007-06-01

    Full Text Available Ecology of Anopheles dthali was studied in Bandar Abbas County, where there is indigenous malaria. Anopheles dthali plays as a secondary malaria vector in the region. It is active throughout the year in mountainous area with two peaks of activity, whereas in coastal area it has one peak. There is no report of hibernation or aestivation for this species in the re¬gion. Precipitin tests on specimens from different parts showed that 15.6-20.8% were positive for human blood. This species usually rests outdoors. It has different larval habitats. Insecticides susceptibility tests on adult females exhibited susceptibil¬ity to all insecticides recommended by WHO. LT50 for the currently used insecticide, lambda-cyhalothrin, is measured less than one minute. The irritability tests to pyrethroid insecticides, showed that permethrin and lambda-cyhalothrin had more irritancy compared to deltamethrin and cyfluthrin. Larval bioassay using malathion, chlorpyrifos, temephos and fenithrothion did not show any sing of resistance to these larvicides at the diagnostic dose. It is recommended that all the decision makers should consider the results of our study for any vector control measures in the region.

  5. Ecology of Anopheles dthali Patton in Bandar Abbas District, Hormozgan Province, Southern Iran

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    H Vatandoost

    2007-05-01

    Full Text Available Ecology of Anopheles dthali was studied in Bandar Abbas County, where there is indigenous malaria. Anopheles dthali plays as a secondary malaria vector in the region. It is active throughout the year in mountainous area with two peaks of activity, whereas in coastal area it has one peak. There is no report of hibernation or aestivation for this species in the re¬gion. Precipitin tests on specimens from different parts showed that 15.6-20.8% were positive for human blood. This species usually rests outdoors. It has different larval habitats. Insecticides susceptibility tests on adult females exhibited susceptibil¬ity to all insecticides recommended by WHO. LT50 for the currently used insecticide, lambda-cyhalothrin, is measured less than one minute. The irritability tests to pyrethroid insecticides, showed that permethrin and lambda-cyhalothrin had more irritancy compared to deltamethrin and cyfluthrin. Larval bioassay using malathion, chlorpyrifos, temephos and fenithrothion did not show any sing of resistance to these larvicides at the diagnostic dose. It is recommended that all the decision makers should consider the results of our study for any vector control measures in the region.

  6. Optimization of Stocking Density for the Sea Cucumber,Apostichopus japonicus Selenka, Under Feed-Supplement and Non-Feed-Supplement Regimes in Pond Culture

    Institute of Scientific and Technical Information of China (English)

    QIN Chuanxin; DONG Shuanglin; TAN Fuyi; TIAN Xiangli; WANG Fang; DONG Yunwei; GAO Qinfeng

    2009-01-01

    Optimal stocking densities were investigated for the sea cucumber Apostichopus japonicus Selenka under feed-supplement and non-feed-supplement regimes in net enclosures for 333 d. Substantial weight loss occurred during the aestivation phase (AE).Decreased growth rates were also observed during the winter phase (WT). In contrast, sea cucumbers showed rapid growth during the spring (SP) and autumn (AU) phases. Feeding regimes considerably influenced the growth performance, i.e., sea cucumbers grew faster under feed-supplement regime than under non-feed-supplement regime (P< 0.05). The average survival rates of sea cucumbers under feed-supplement regime were higher than those under non-feed-supplement regime for both the autumn phase and spring phase,but the differences were only significant for the latter phase (P<0.05). The fitted B-N curves showed that the optimal stocking densities, in terms of net production, were 22.3 ind. m-2 for feed-supplement regime and 14.1 ind. m-2 for non-feed-supplement regime.

  7. Distribution and habitats of the snail Lymnaea truncatula, intermediate host of the liver fluke Fasciola hepatica, in South Africa

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    K.N. de Kock

    2003-07-01

    Full Text Available This paper focuses on the geographical distribution and habitats of Lymnaea truncatula, the intermediate, snail host of the liver fluke, Fasciola hepatica, as reflected by the 723 samples in the database of the National Freshwater Snail Collection, Potchefstroom, South Africa. The 221 different loci (1/16-degree squares on record reflect an extensive but discontinuous distribution, except in Lesotho and in parts of the Mpumalanga, Gauteng and North West provinces of South Africa. Although recorded from 12 different types of waterbody, it was mostly (42.0 % recovered from swamps. Most samples (45.8 % were collected in habitats with slow-flowing water. A muddy substratum was recorded for 62.5 % of the samples. Most samples (86.3 % were collected in habitats with a mean annual air temperature of 10-20 o C, and more than 69 % came from localities with a mean annual rainfall of 600-900mm. An integrated decision tree constructed from the data indicated that temperature and types of waterbody play a decisive role in determining the presence of L. truncatula in a given area. A temperature index calculated for all mollusc species ranked L. truncatula second in a total of 53 species according to its association with low temperatures. It remains to be established whether its distribution is indeed discontinuous, and whether its preference for a particular habitat, amphibious habits and ability to aestivate could have resulted in some populations having been overlooked during surveys.

  8. On whose shoulders we stand - the pioneering entomological discoveries of Károly Sajó.

    Science.gov (United States)

    Vig, Károly

    2011-01-01

    The excellence of Károly Sajó as a researcher into Hungary's natural history has been undeservedly neglected. Yet he did lasting work, especially in entomology, and a number of his discoveries and initiatives were before their time.Born in 1851 in Győr, he received his secondary education there and went to Pest University. He taught in a grammar school in 1877-88 before spending seven years as an entomologist at the National Phylloxera Experimental Station, later the Royal Hungarian State Entomological Station. Pensioned off at his own request in 1895, he moved to Őrszentmiklós, where he continued making entomological observations on his own farm and wrote the bulk of his published materials: almost 500 longer or shorter notes, articles and books, mainly on entomological subjects.Sajó was among the first in the world to publish in 1896 a study of how the weather affects living organisms, entitled Living Barometers. His Sleep in Insects, which appeared in the same year, described his discovery, from 1895 observations of the red turnip beetle, Entomoscelis adonidis (Pallas, 1771), of aestivation in insects - in present-day terms diapause.It was a great loss to universal entomology when Sajó ceased publishing about 25 years before his death. His unpublished notes, with his library and correspondence, were destroyed in the World War II. His surviving insect collection is now kept in the Hungarian Natural History Museum, Budapest.

  9. On whose shoulders we stand – the pioneering entomological discoveries of Károly Sajó

    Directory of Open Access Journals (Sweden)

    Karoly Vig

    2011-12-01

    Full Text Available The excellence of Károly Sajó as a researcher into Hungary’s natural history has been undeservedly neglected. Yet he did lasting work, especially in entomology, and a number of his discoveries and initiatives were before their time.Born in 1851 in Győr, he received his secondary education there and went to Pest University. He taught in a grammar school in 1877–88 before spending seven years as an entomologist at the National Phylloxera Experimental Station, later the Royal Hungarian State Entomological Station. Pensioned off at his own request in 1895, he moved to Őrszentmiklós, where he continued making entomological observations on his own farm and wrote the bulk of his published materials: almost 500 longer or shorter notes, articles and books, mainly on entomological subjects.Sajó was among the first in the world to publish in 1896 a study of how the weather affects living organisms, entitled Living Barometers. His Sleep in Insects, which appeared in the same year, described his discovery, from 1895 observations of the red turnip beetle, Entomoscelis adonidis (Pallas 1771, of aestivation in insects – in present-day terms diapause.It was a great loss to universal entomology when Sajó ceased publishing about 25 years before his death. His unpublished notes, with his library and correspondence, were destroyed in the World War II. His surviving insect collection is now kept in the Hungarian Natural History Museum, Budapest.

  10. Comparative evaluation of haemagglutination potential of haemolymph from two species of giant African land snails (Archachatina marginata and Achatina achatina).

    Science.gov (United States)

    Abiona, John Adesanya; Akinduti, Paul Akinniyi; Oyekunle, Mufutao Atanda; Osinowo, Olusegun Ayodeji; Onagbesan, A Okanlawon Mohammed

    2014-05-01

    A comparative study was conducted to evaluate haemagglutination potential in the haemolymph of two species of giant African land snails (Archachatina marginata and Achatina achatina). Three liveweight groups of snails (150 g) were used with 4 replicates per liveweight per species for haemagglutination assay (HA). The effect of aestivation on haemagglutination potential was also evaluated. Erythrocytes (2%) from cattle, sheep, goat and chicken were used for HA assay. Results showed that agglutinin-like substances that agglutinate erythrocytes of sheep, goat, cattle and chicken were present in the haemolymph of the two species of giant African land snails. Effect of species was found to be significant (P Snail liveweight had no significant effect (P > 0.05) on agglutinin content of the haemolymph in both species. Agglutination level depended on the source of erythrocyte used. Sheep erythrocyte recorded the highest haemagglutination titre, followed by goat, cattle, and chicken in that order. To our knowledge, this is the first evidence that Giant African land snails (GALS) haemolymph contain agglutinins as previously reported for Helix species. This evidence may be the basis for its survivability in the wild and thus establish the use of GALS for African herbal medicinal applications.

  11. An Overview of Seasonal Changes in Oxidative Stress and Antioxidant Defence Parameters in Some Invertebrate and Vertebrate Species

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    Gagan Bihari Nityananda Chainy

    2016-01-01

    Full Text Available Antioxidant defence system, a highly conserved biochemical mechanism, protects organisms from harmful effects of reactive oxygen species (ROS, a by-product of metabolism. Both invertebrates and vertebrates are unable to modify environmental physical factors such as photoperiod, temperature, salinity, humidity, oxygen content, and food availability as per their requirement. Therefore, they have evolved mechanisms to modulate their metabolic pathways to cope their physiology with changing environmental challenges for survival. Antioxidant defences are one of such biochemical mechanisms. At low concentration, ROS regulates several physiological processes, whereas at higher concentration they are toxic to organisms because they impair cellular functions by oxidizing biomolecules. Seasonal changes in antioxidant defences make species able to maintain their correct ROS titre to take various physiological functions such as hibernation, aestivation, migration, and reproduction against changing environmental physical parameters. In this paper, we have compiled information available in the literature on seasonal variation in antioxidant defence system in various species of invertebrates and vertebrates. The primary objective was to understand the relationship between varied biological phenomena seen in different animal species and conserved antioxidant defence system with respect to seasons.

  12. Fungal Control of Pathogenic Fungi Isolated From Some Wild Plants in Taif Governorate, Saudi Arabia

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    Abou-Zeid, A. M.

    2008-01-01

    Full Text Available Twenty two plants were collected from Taif Governorate and identified as: Aerva lanata, Arnebia hispidissima, Artemisia judaica, Artemisia monosperma, Asphodelus aestives, Avena barbata, Capparis dcidua, Eucalyptus globulus, Euphorbia glomerifera, Foeniculum vulgare, Forsskaolea tenacissima, Juniperus procera, Launaea mucronata, Launaea sonchoides, Medicago sativa, Opuntia ficus, Phagnalon sinaicum, Prunus persica, Pulicaria crispa, Punica granatum, Rumex dentatus and Trichodesma calathiforme. Pathogenic fungi were isolated from some of these plants and identified as Alternaria alternata, Cephalosporium madurae, Cladosporium herbarum, Fusarium oxysporum, Humicola grisea, Penicillium chrysogenum and Ulocladium botrytis. Four antagonistic isolates were tested, 2 from Gliocladium fungus and 2 from Trichoderma fungus. We found that all the four antagonistic isolates (G. deliquescens, G. virens, T. viride and T. hamatum significantly inhibited the radial growth of the pathogenic fungi tested, with different ratios. The results indicated that the antibiotics produced by the antagonists were more effective than the fungus itself and differ with different fungi. Coating plant stems with antagonists or with antagonist extracts reduce the severity of the disease but not prevent it in all tested pathogens.

  13. Application of morphologic burrow architects: lungfish or crayfish?

    Science.gov (United States)

    Hasiotis, Stephen T.; Mitchell, Charles E.; Dubiel, Russell R.

    1993-01-01

    A methodology for trace fossil identification using burrowing signatures is tested by evaluating ancient and modern lungfish and crayfish burrows and comparing them to previously undescribed burrows in a stratigraphic interval thought to contain both lungfish and crayfish burrows. Permian burrows that bear skeletal remains of the lungfish Gnathorhiza, from museum collections, were evaluated to identify unique burrow morphologies that could be used to distinguish lungfish from crayfish burrows when fossil remains are absent. The lungfish burrows were evaluated for details of the burrowing mechanism preserved in the burrow morphologies together forming burrowing signatures and were compared to new burrows in the Chinle Formation of western Colorado to test the methodology of using burrow signatures to identify unknown burrows. Permian lungfish aestivation burrows show simple, nearly vertical, unbranched architectures and relatively smooth surficial morphologies with characteristic quasi‐horizontal striae on the burrow walls and vertical striae on the bulbous terminus. Burrow lengths do not exceed 0.5 m. In contrast, modern and ancient crayfish burrows exhibit simple to highly complex architectures with highly textured surficial morphologies. Burrow lengths may reach 4 to 5 m. Burrow morphologies unlike those identified in Gnathorhiza aestivation burrows were found in four burrow groups from museum collections. Two of these groups exhibit simple architectures and horizontal striae that were greater in sinuosity and magnitude, respectively. One of these burrows contains the remains of Lysorophus, but the burrow surface reveals no reliable surficial characteristics. It is not clear whether Lysorophus truly burrowed or merely occupied a pre‐existing structure. The other two groups exhibit surficial morphologies similar to those found on modern and ancient crayfish burrows and may provide evidence of freshwater crayfish in the Permian. Burrows from the Upper Triassic

  14. Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes.

    Science.gov (United States)

    Chew, S F; Ip, Y K

    2014-03-01

    With the development of air-breathing capabilities, some fishes can emerge from water, make excursions onto land or even burrow into mud during droughts. Air-breathing fishes have modified gill morphology and morphometry and accessory breathing organs, which would tend to reduce branchial ammonia excretion. As ammonia is toxic, air-breathing fishes, especially amphibious ones, are equipped with various strategies to ameliorate ammonia toxicity during emersion or ammonia exposure. These strategies can be categorized into (1) enhancement of ammonia excretion and reduction of ammonia entry, (2) conversion of ammonia to a less toxic product for accumulation and subsequent excretion, (3) reduction of ammonia production and avoidance of ammonia accumulation and (4) tolerance of ammonia at cellular and tissue levels. Active ammonia excretion, operating in conjunction with lowering of ambient pH and reduction in branchial and cutaneous NH₃ permeability, is theoretically the most effective strategy to maintain low internal ammonia concentrations. NH₃ volatilization involves the alkalization of certain epithelial surfaces and requires mechanisms to prevent NH₃ back flux. Urea synthesis is an energy-intensive process and hence uncommon among air-breathing teleosts. Aestivating African lungfishes detoxify ammonia to urea and the accumulated urea is excreted following arousal. Reduction in ammonia production is achieved in some air-breathing fishes through suppression of amino acid catabolism and proteolysis, or through partial amino acid catabolism leading to alanine formation. Others can slow down ammonia accumulation through increased glutamine synthesis in the liver and muscle. Yet, some others develop high tolerance of ammonia at cellular and tissue levels, including tissues in the brain. In summary, the responses of air-breathing fishes to ameliorate ammonia toxicity are many and varied, determined by the behaviour of the species and the nature of the environment in

  15. Identification and functional characterisation of 5-HT4 receptor in sea cucumber Apostichopus japonicus (Selenka)

    Science.gov (United States)

    Wang, Tianming; Yang, Zhen; Zhou, Naiming; Sun, Lina; Lv, Zhenming; Wu, Changwen

    2017-01-01

    Serotonin (5-HT) is an important neurotransmitter and neuromodulator that controls a variety of sensory and motor functions through 5-HT receptors (5-HTRs). The 5-HT4R subfamily is linked to Gs proteins, which activate adenylyl cyclases (ACs), and is involved in many responses in peripheral organs. In this study, the 5-HT4R from Apostichopus japonicus (Aj5-HT4R) was identified and characterised. The cloned full-length Aj5-HT4R cDNA is 1,544 bp long and contains an open reading frame 1,011 bp in length encoding 336 amino acid proteins. Bioinformatics analysis of the Aj5-HT4R protein indicated this receptor was a member of class A G protein coupled receptor (GPCR) family. Further experiments using Aj5-HT4R-transfected HEK293 cells demonstrated that treatment with 5-HT triggered a significant increase in intracellular cAMP level in a dose-dependent manner and induced a rapid internalisation of Aj5-HT4R fused with enhanced green fluorescent protein (Aj5-HT4R-EGFP) from the cell surface into the cytoplasm. In addition, the transcriptional profiles of Aj5-HT4R in aestivating A. japonicas and phosphofructokinase (AjPFK) in 5-HT administrated A. japonicus have been analysed by real-time PCR assays. Results have led to a basic understanding of Aj5-HT4R in A. japonicus, and provide a foundation for further exploration of the cell signaling and regulatory functions of this receptor. PMID:28059140

  16. What parts of the US mainland are climatically suitable for invasive alien pythons spreading from Everglades National Park?

    Science.gov (United States)

    Rodda, G.H.; Jarnevich, C.S.; Reed, R.N.

    2009-01-01

    The Burmese Python (Python molurus bivittatus) is now well established in southern Florida and spreading northward. The factors likely to limit this spread are unknown, but presumably include climate or are correlated with climate. We compiled monthly rainfall and temperature statistics from 149 stations located near the edge of the python's native range in Asia (Pakistan east to China and south to Indonesia). The southern and eastern native range limits extend to saltwater, leaving unresolved the species' climatic tolerances in those areas. The northern and western limits are associated with cold and aridity respectively. We plotted mean monthly rainfall against mean monthly temperature for the 149 native range weather stations to identify the climate conditions inhabited by pythons in their native range, and mapped areas of the coterminous United States with the same climate today and projected for the year 2100. We accounted for both dry-season aestivation and winter hibernation (under two scenarios of hibernation duration). The potential distribution was relatively insensitive to choice of scenario for hibernation duration. US areas climatically matched at present ranged up the coasts and across the south from Delaware to Oregon, and included most of California, Texas, Oklahoma, Arkansas, Louisiana, Mississippi, Alabama, Florida, Georgia, and South and North Carolina. By the year 2100, projected areas of potential suitable climate extend northward beyond the current limit to include parts of the states of Washington, Colorado, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, New Jersey, and New York. Thus a substantial portion of the mainland US is potentially vulnerable to this ostensibly tropical invader. ?? 2008 Springer Science+Business Media B.V.

  17. Ecological implications of metabolic compensation at low temperatures in salamanders

    Directory of Open Access Journals (Sweden)

    Alessandro Catenazzi

    2016-05-01

    Full Text Available Global warming is influencing the biology of the world’s biota. Temperature increases are occurring at a faster pace than that experienced by organisms in their evolutionary histories, limiting the organisms’ response to new conditions. Mechanistic models that include physiological traits can help predict species’ responses to warming. Changes in metabolism at high temperatures are often examined; yet many species are behaviorally shielded from high temperatures. Salamanders generally favor cold temperatures and are one of few groups of metazoans to be most species-rich in temperate regions. I examined variation in body temperature, behavioral activity, and temperature dependence of resting heart rate, used as a proxy for standard metabolic rate, in fire salamanders (Salamandra salamandra. Over 26 years, I found that salamanders are behaviorally active at temperatures as low as 1 °C, and aestivate at temperatures above 16 °C. Infrared thermography indicates limited thermoregulation opportunities for these nocturnal amphibians. Temperature affects resting heart rate, causing metabolic depression above 11 °C, and metabolic compensation below 8 °C: heart rate at 3 °C is 224% the expected heart rate. Thus, salamanders operating at low temperatures during periods of peak behavioral activity are able to maintain a higher metabolic rate than the rate expected in absence of compensation. This compensatory mechanism has important ecological implications, because it increases estimated seasonal heart rates. Increased heart rate, and thus metabolism, will require higher caloric intake for field-active salamanders. Thus, it is important to consider a species performance breadth over the entire temperature range, and particularly low temperatures that are ecologically relevant for cold tolerant species such as salamanders.

  18. Environmentally cued hatching in reptiles.

    Science.gov (United States)

    Doody, J S

    2011-07-01

    Evidence is accumulating for the widespread occurrence of environmentally cued hatching (ECH) in animals, but its diversity and distribution across taxa are unknown. Herein I review three types of ECH in reptiles: early hatching, delayed hatching, and synchronous hatching. ECH is currently known from 43 species, including turtles, crocodilians, lizards, snakes, tuatara, and possibly worm lizards. Early hatching caused by physical disturbance (e.g., vibrations) is the most commonly reported ECH across all groups; although it apparently serves an antipredator function in some species, its adaptive value is unknown in most. Delayed hatching, characterized by metabolic depression or embryonic aestivation, and sometimes followed by a hypoxic cue (flooding), occurs in some turtles and possibly in monitor lizards and crocodilians; in some of these species delayed hatching serves to defer hatching from the dry season until the more favorable conditions of the wet season. Synchronous hatching, whereby sibling eggs hatch synchronously despite vertical thermal gradients in the nest, occurs in some turtles and crocodilians. Although vibrations and vocalizations in hatching-competent embryos can stimulate synchronous hatching, cues promoting developmentally less advanced embryos to catch up with more advanced embryos have not been confirmed. Synchronous hatching may serve to dilute predation risk by promoting synchronous emergence or reduce the period in which smells associated with hatching can attract predators to unhatched eggs. Within species, advancing our understanding of ECH requires three types of studies: (1) experiments identifying hatching cues and the plastic hatching period, (2) experiments disentangling hypotheses about multiple hatching cues, and (3) investigations into the environmental context in which ECH might evolve in different species (major predators or abiotic influences on the egg, embryo, and hatchling). Among species and groups, surveys for ECH are

  19. Torpor in mammals: types, species and patterns%哺乳动物的蛰眠:类型、物种分布与模式

    Institute of Scientific and Technical Information of China (English)

    杨明; 王德华

    2011-01-01

    哺乳动物的蛰眠(包括冬眠、夏眠和日蛰眠等)是最具吸引力的生命现象之一,是动物应对寒冷、食物短缺、干旱等不良环境条件的适应策略之一.冬眠生理学(生态学)研究具有重要的理论和实际意义.国际学术界在该领域发展比较迅速,国内发展相对缓慢.本文从哺乳动物蛰眠的季节和持续时间、蛰眠期间所利用能量的来源和贮存方式、启动蛰眠的信号来源等方面综述了哺乳动物蛰眠的类型;介绍了蛰眠的哺乳动物物种的系统学分布;并对温带或北极动物的冬眠和冬眠阵及其各阶段的体温和代谢率变化特征、日温剧烈波动环境下的冬眠特征以及日眠和日眠阵等方面进行了概括介绍,以期能促进国内相关领域的发展.%Torpor ( including hibernation, aestivation, and daily torpor) in mammals is one of the most attractive physiological phenomena in life science.Some mammal species use torpor to survive harsh environments such as cold, food shortage and drought.Physiological and/or ecological research into torpor of mammals has potential implications in biomedicine in situations such as trauma treatment, organ transplantation and spaceflight.This review briefly introduces several aspects of torpor in mammals: 1 ) Types of torpor in mammals according to the season and duration of mammalian torpor, the source and storage form of the fuel used in torpor, and the signals initiating torpor.2) The systematic distribution of the mammal species utilized torpors.3 ) The general properties in body temperature and metabolic rate which occurr in hibernation and hibernation bouts of mammals in temperate and arctic zone, and in the tropics where the diurnal hibemacula temperatures fluctuate acutely.We also introduce the patterns of other kinds of torpor, such as daily torpor.

  20. Study on Natural Distribution and Biological Characteristics of Lycium ruthenicum in Yanqi Basin%焉耆盆地黑果枸杞自然分布特点及其生物特性研究

    Institute of Scientific and Technical Information of China (English)

    何文革; 那松曹克图; 吾其尔; 吴春焕; 赵洁; 王瑛; 李玉霞

    2015-01-01

    对新疆焉耆盆地黑果枸杞的自然分布及其生物特性进行了研究,结果表明:黑果枸杞是典型的根蘖类无性系植物,并兼具有性和无性两套繁殖系统,其自然分布涵盖了焉耆盆地平原荒漠和低地草甸2类8个亚类的草地类型,占盆地10个亚类草地类型的80%,并在农区广泛分布,为焉耆盆地的广布种;其根系由水平根和地下垂直茎以及季节性分生存在的不定根组成;其有性繁育系统为异交型,并具花的色泽变化和“两花两果”特性;其无性繁育由水平根以根蘖克隆的形式繁殖;其单体群落中看似独立的植株个体,却是由地下由水平根相连的一个有机“整体”,并具有相同的遗传基因;其植株具有夏眠及被掩埋后仍能存活并变性的特性。%Natural distribution and biological characteristics of Lycium ruthenicum in Xinjiang Yanqi Basin was studied.The results showed that Lycium ruthenicum was typical clonal plant which belonged to root sucker class,and had two sets of reproductive system,sexual and asexual.Its natural distribution covered 2 classes and 8 subclasses of the desert plains of Yanqi Basin and lowland meadow grassland types,accounting for 80%of the 10 subgenera grassland types in basin,and widely distributed in rural areas in Yanqi Basin.The root was composed of horizontal root and vertical underground stem and adventitious root which meristematic existed seasonal.The sexual breeding system were outcrossing,with flowers color change and "two flowers of two fruit" characteristics,the asexual breeding system reproduction by cloning root suckers with horizontal root.The monomer seemed independent individual plants in the community,but connected by underground horizontal root of an organic"whole",and had the same genetic. Plant with properties that after aestivation and buried still could survive and degeneration.

  1. Possible Effects of Sea Level Rise in the Future on the Coral Reef in Weizhou Island%未来海平面上升对涠洲岛珊瑚礁的可能影响

    Institute of Scientific and Technical Information of China (English)

    汤超莲; 周雄; 郑兆勇; 莫少华; 唐旺先

    2013-01-01

    Based on historical records of rainfall, salinity, PH, sea level, Max wave height and ecological surveys (Reef Check), we analyzed the effects of climate change and sea level rise on the coral reef in Weizhou Island. Our results suggest that 1) The rainfall, water salinity and PH are in the coral growth suitable range in Weizhou Island with an average annual rainfall of 1388mm, water salinity of 32.1 and PH of between 8.0 and 8.23; 2) Once-in-a-century hydrological extrema obtained from P- formulaⅢ are that, annual rainfall 2313mm, Max sea level 514cm and Max wave height 6.1m;3) the skeletal extension rate of Porites coral is 6~8mm/a, heigher than sea level rise rate (2.2mm/a) in Weizhou Island. The maximum tide range is 450~500cm, when the minimum tide occurs in the aestival daytime, coral bleaching will ascend in frequency. 4) If 512cm of maximum tide hight and 580cm of maximum wave height both occur when the sea level rise 30cm in the future, the corel reef in Weizhou Island will not be destroyed thoroughly.%  根据涠洲岛珊瑚样品资料和涠洲岛海洋站实测雨量、盐度、pH、潮位、最大波高及珊瑚普查历史资料,分析气候变化、海平面上升对涠洲岛珊瑚礁的可能影响.结果显示:1)涠洲岛的多年平均雨量为1388 mm,多年平均盐度为32.1,目前海水pH值为8.0~8.23,均在珊瑚生长合适范围内;2)用P-Ⅲ型算式得出涠洲岛的水文要素百年一遇极值为:年雨量2313 mm,最高潮位514 cm,最大波高6.1 m;3)涠洲岛珊瑚生长率(6~8 mm/a)大于海平面上升率(2.2 mm/a),涠洲岛最大潮差为450~500 cm,夏季白天遇低潮时,会增加珊瑚白化概率;4)若未来海平面上升30 cm,遇上512 cm高潮位与580 cm最大波高,不会对涠洲岛珊瑚礁造成毁灭性破坏.

  2. Variaciones en la estacionalidad de polen y esporas fúngicas en la atmósfera de la ciudad de La Plata (Argentina Seasonal variation of pollen and fungal spores in the atmosphere of Plata city (Argentina

    Directory of Open Access Journals (Sweden)

    Daniela S Nitiu

    2011-12-01

    fungal component, spores from Oomycota, Zygomycota, Myxomycota Ascomycota, and Basidiomycota were identified. These bioaerosols were present throughout the year in high concentrations being more abundant in spring - summer time. Imperfect Fungi mitospores were dominant in the cloud exceeding 44% of the Spore Index. The major peak was in february due to Cladosporium spores. We identified two seasonal periods in which, high concentrations of pollen and fungal spores occurred simultaneously. The first takes place in spring and consists of elements of Platanus, Fraxinus and Aspergillus / Penicillium and the second peak is aestival and involves Ambrosia, Alternaria and Cladosporium.

  3. Drastic Population Size Change in Two Populations of the Golden-Striped Salamander over a Forty-Year Period—Are Eucalypt Plantations to Blame?

    Directory of Open Access Journals (Sweden)

    Jan W. Arntzen

    2015-07-01

    Full Text Available Over the last half century the Iberian peninsula has seen the large scale planting of exotic gum trees (Eucalyptus sp. therewith reducing space for native wildlife. An additional effect of the gum tree plantations may be the lowering of the water table in adjacent streams, to which amphibian species with a larval niche in the running sections of small streams would be especially susceptible. In northwestern Iberia that niche is occupied by the Golden-striped salamander, Chioglossa lusitanica. I here report on the demographic trends of two C. lusitanica populations over a forty-year period, in two areas of one mountain range near Porto in northwestern Portugal. In both areas advantage was taken of the migration pattern of C. lusitanica to sites for aestivation and breeding in summer and fall. The area of the Silveirinhos brook was transformed in a plantation of gum trees shortly after the research started, while the area of Poço do Inferno remained virtually unaffected. At Silveirinhos the adult C. lusitanica population declined by one or two orders of magnitude, from ca. 1500 individuals to less than 50 at present. Demographic models that operate under a uniform larval mortality yielded population sizes that are compatible with field observations, including the late onset of the decline at 14 or more years after the planting of the gum trees and the near-extinction at year 32. An alternative reason for the relatively recent population collapse of C. lusitanica may have been disease, but no sick individuals or corpses have become available for clinical investigation. Conversely, the control population at Poço do Inferno increased in size by a factor of five or more. These data support the hypothesis that gum tree plantations have a strong negative effect on C. lusitanica. The population size increase at Poço do Inferno is probably attributable to the installation of wastewater treatment in the adjacent town of Valongo, with a discharge in the

  4. Paleoenvironmental and paleoclimatic significance of freshwater bivalves in the Upper Jurassic Morrison Formation, Western Interior, USA

    Science.gov (United States)

    Good, Steven C.

    2004-05-01

    Freshwater unionid bivalves are spatially and temporally distributed throughout the Morrison depositional basin, and locally dominate the biomass of many aquatic depositional environments. Two bivalve assemblages are identified. Within-channel assemblages are death assemblages that have been transported and may represent mixed assemblages from multiple communities. These assemblages are predominately disarticulated, in current stable orientations, and composed of higher stream velocity ecophenotypes (medium size, lanceolate form, and very thick shells). The floodplain-pond assemblages are disturbed neighborhood assemblages in the mudstones inhabited during life. The bivalves are predominately articulated, variable in size, and composed of low stream velocity ecophenotypes (large maximum sizes, ovate shell shapes, and thinner shells). The glochidial parasitic larval stage of unionid bivalves provides an effective means of dispersing species throughout drainage basins. These larvae attach to fish and are carried through the fluvial drainage where the larvae detach and establish new bivalve communities. Preliminary paleobiogeographic analyses are drawn at the genus level because of the need to reevaluate bivalve species of the Morrison. Unio spp. and Vetulonaia spp. are widespread throughout the Morrison depositional basin, but Hadrodon spp. are restricted to the eastern portion of the Colorado Plateau during Salt Wash Member deposition, suggesting that Salt Wash drainage was isolated from other contemporaneous regions of the basin. Bivalves from five localities in the Morrison Formation were thin-sectioned for growth band analysis. Growth bands of modern unionid bivalves are produced when the valves are forced to close. Closure can produce annual growth bands in response to seasonal variation, such as temperature-induced hibernation, or precipitation-induced aestivation or turbidity. Pseudoannual growth bands form from non-cyclical events such as predation attacks or