Sample records for aestivation
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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. Copyright © 2016 Elsevier Inc. All rights reserved.
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Biochemical evaluation of aestivation and starvation in two snail ...
African Journals Online (AJOL)
hope&shola
2010-11-08
Nov 8, 2010 ... food uptake ceases, water loss occurs and the snails are not able to rid .... Fasting glucose decreased in both aestivating and starved B. rohlfsi snails ... significant muscle wastage during aestivation and starvation. It has been ...
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Directory of Open Access Journals (Sweden)
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
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Zhu, Aijun; Chen, Muyan; Zhang, Xiumei; Storey, Kenneth B
2016-12-05
The sea cucumber, Apostichopus japonicus, is a good model for studying environmentally-induced aestivation by a marine invertebrate. One of the central requirements of aestivation is the repression of energy-expensive cellular processes such as cell cycle progression. The present study identified the gene structure of the cell cycle regulator, cyclin B, and detected the expression levels of this gene over three stages of the annual aestivation-arousal cycle. Furthermore, the DNA methylation characteristics of cyclin B were analyzed in non-aestivation and deep-aestivation stages of sea cucumbers. We found that the cyclin B promoter contains a CpG island, three CCAAT-boxes and three cell cycle gene homology regions (CHRs). Application of qRT-PCR analysis showed significant downregulation of cyclin B transcript levels during deep-aestivation in comparison with non-aestivation in both intestine and longitudinal muscle, and these returned to basal levels after arousal from aestivation. Methylation analysis of the cyclin B core promoter revealed that its methylation level showed significant differences between non-aestivation and deep-aestivation stages (p<0.05) and interestingly, a positive correlation between Cyclin B transcripts expression and methylation levels of the core promoter was also observed. Our findings suggest that cell cycle progression may be reversibly arrested during aestivation as indicated by the changes in cyclin B expression levels and we propose that DNA methylation is one of the regulatory mechanisms involved in cyclin B transcriptional variation. Copyright © 2016 Elsevier B.V. All rights reserved.
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The role of snail aestivation in transmission of schistosomiasis in ...
African Journals Online (AJOL)
Aestivation therefore plays an important role in maintaining the transmission of schistosomiasis. This review assesses the possible impacts of climate change on the temporal and spatial distribution of schistosomiasis-transmitting snails with special emphasis on aestivation, and discusses the effect of schistosome infection ...
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Wang, Tianming; Yang, Hongsheng; Zhao, Huan; Chen, Muyan; Wang, Bing
2011-11-01
The sea cucumber, Apostichopus japonicus, 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.
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Chen, Muyan; Storey, Kenneth B
2014-02-01
The sea cucumber Apostichopus japonicus withstands high water temperatures in the summer by suppressing its metabolic rate and entering a state of aestivation. We hypothesized that changes in the expression of miRNAs could provide important post-transcriptional regulation of gene expression during hypometabolism via control over mRNA translation. The present study analyzed profiles of miRNA expression in the sea cucumber respiratory tree using Solexa deep sequencing technology. We identified 279 sea cucumber miRNAs, including 15 novel miRNAs specific to sea cucumber. Animals sampled during deep aestivation (DA; after at least 15 days of continuous torpor) were compared with animals from a non-aestivation (NA) state (animals that had passed through aestivation and returned to an active state). We identified 30 differentially expressed miRNAs ([RPM (reads per million) >10, |FC| (|fold change|)≥1, FDR (false discovery rate)<0.01]) during aestivation, which were validated by two other miRNA profiling methods: miRNA microarray and real-time PCR. Among the most prominent miRNA species, miR-124, miR-124-3p, miR-79, miR-9 and miR-2010 were significantly over-expressed during deep aestivation compared with non-aestivation animals, suggesting that these miRNAs may play important roles in metabolic rate suppression during aestivation. High-throughput sequencing data and microarray data have been submitted to the GEO database with accession number: 16902695. Copyright © 2014 Elsevier B.V. All rights reserved.
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Krupanidhi, S; Raghavaiah, K; Padmanabha Naidu, B; Ramamurthi, R [Sri Venkateswara Univ., Tirupati (India). Dept. of Zoology
1978-03-01
The percent decrease of glycogen content in all the tissues investigated is more in 20-days starved snails than the 4-months aestivated snails when compared to active snails. Recovery of administered glucose-U/sup 14/C in the respiratory CO/sub 2/ is 42.27 % in active snails, whereas it is 8.81 % and 26.09 % in aestivated and starved snails respectively. Maximum levels of incorporation labelled glucose were found at 18 hr in all the tissues and the rate of incorporation was greatly elevated in the tissues of aestivated and starved snails. The causes for the difference in the rates of incorporation and the utilization of glycogen in active, aestivated and starved snails are discussed.
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Zhao, Ye; Chen, Muyan; Storey, Kenneth B; Sun, Lina; Yang, Hongsheng
2015-03-01
DNA methylation plays an important role in regulating transcriptional change in response to environmental stimuli. In the present study, DNA methylation levels of tissues of the sea cucumber Apostichopus japonicus were analyzed by the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) technique over three stages of the aestivation cycle. Overall, a total of 26,963 fragments were amplified including 9112 methylated fragments among four sea cucumber tissues using 18 pairs of selective primers. Results indicated an average DNA methylation level of 33.79% for A. japonicus. The incidence of DNA methylation was different across tissue types in the non-aestivation stage: intestine (30.16%), respiratory tree (27.61%), muscle (27.94%) and body wall (56.25%). Our results show that hypermethylation accompanied deep-aestivation in A. japonicus, which suggests that DNA methylation may have an important role in regulating global transcriptional suppression during aestivation. Further analysis indicated that the main DNA modification sites were focused on intestine and respiratory tree tissues and that full-methylation but not hemi-methylation levels exhibited significant increases in the deep-aestivation stage. Copyright © 2014 Elsevier Inc. All rights reserved.
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Zhao, Ye; Chen, Muyan; Wang, Tianming; Sun, Lina; Xu, Dongxue; Yang, Hongsheng
2014-11-01
Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) is a technique that is widely used for gene expression analysis, and its accuracy depends on the expression stability of the internal reference genes used as normalization factors. However, many applications of qRT-PCR used housekeeping genes as internal controls without validation. In this study, the expression stability of eight candidate reference genes in three tissues (intestine, respiratory tree, and muscle) of the sea cucumber Apostichopus japonicus was assessed during normal growth and aestivation using the geNorm, NormFinder, delta CT, and RefFinder algorithms. The results indicate that the reference genes exhibited significantly different expression patterns among the three tissues during aestivation. In general, the β-tubulin (TUBB) gene was relatively stable in the intestine and respiratory tree tissues. The optimal reference gene combination for intestine was 40S ribosomal protein S18 (RPS18), TUBB, and NADH dehydrogenase (NADH); for respiratory tree, it was β-actin (ACTB), TUBB, and succinate dehydrogenase cytochrome B small subunit (SDHC); and for muscle it was α-tubulin (TUBA) and NADH dehydrogenase [ubiquinone] 1 α subcomplex subunit 13 (NDUFA13). These combinations of internal control genes should be considered for use in further studies of gene expression in A. japonicus during aestivation.
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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.
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Hiong, Kum Chew; Loong, Ai May; Chew, Shit Fun; Ip, Yuen Kwong
2005-12-01
The objectives of this study are to determine whether a full complement of ornithine-urea cycle (OUC) enzymes is present in the hepatopancreas of the giant African snail Achatina fulica, and to investigate whether the rate of urea synthesis and the OUC capacity can be up-regulated during 23 days of fasting or aestivation, or 24 hr post-injection with NH(4)Cl (10 micromol g(-1) snail) into the foot muscle. A. fulica is ureotelic and a full complement of OUC enzymes, including carbamoyl phosphate synthetase III (CPS III), was detected from its hepatopancreas. There were significant increases in the excretion of NH(4)(+), NH(3) and urea in fasting A. fulica. Fasting had no significant effect on the tissue ammonia contents, but led to a progressive accumulation of urea, which was associated with an 18-fold increase in the rate of urea synthesis. Because fasting took place in the presence of water and because there was no change in water contents in the foot muscle and hepatopancreas, it can be concluded that the function of urea accumulation in fasting A. fulica was unrelated to water retention. Aestivation in arid conditions led to a non-progressive accumulation of urea in A. fulica. During the first 4 days and the last 3 days of the 23-day aestivation period, experimental snails exhibited significantly greater rates of urea synthesis compared with fasted snails. These increases were associated with significant increases in activities of various OUC enzymes, except CPS III, in the hepatopancreas. However, the overall urea accumulation in snails aestivated and snails fasted for 23 days were comparable. Therefore, the classical hypothesis that urea accumulation occurred to prevent water loss through evaporation during aestivation in terrestrial pulmonates may not be valid. Surprisingly, there were no accumulations of ammonia in the foot muscle and hepatopancreas of A. fulica 12 or 24 hr after NH(4)Cl was injected into the foot muscle. In contrast, the urea content in
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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
2016-01-01
African lungfishes can undergo long periods of aestivation on land during drought. During aestivation, lungfishes are confronted with desiccation and dehydration, and their gills become non-functional and covered with a thick layer of dried mucus. Aquaporins (Aqps) are a superfamily of integral membrane proteins which generally facilitate the permeation of water through plasma membranes. This study aimed to obtain the complete cDNA coding sequences of aqp1 and aqp3 from the gills of Protopterus annectens , and to determine their branchial mRNA and protein expression levels during the induction, maintenance and arousal phases of aestivation. Dendrogramic analyses of the deduced Aqp1 and Aqp3 amino acid sequences of P. annectens revealed their close relationships with those of Latimeria chalumnae and tetrapods. During the induction phase, there were significant decreases in the transcript levels of aqp1 and aqp3 in the gills of P. annectens , but the branchial Aqp1 and Aqp3 protein abundance remained unchanged. As changes in transcription might precede changes in translation, this could be regarded as an adaptive response to decrease the protein abundance of Aqp1 and Aqp3 in the subsequent maintenance phase of aestivation. As expected, the branchial transcript levels and protein abundance of aqp1 /Aqp1 and aqp3 /Aqp3 were significantly down-regulated during the maintenance phase, probably attributable to the shutdown of branchial functions and the cessation of volume regulation of branchial epithelial cells. Additionally, these changes could reduce the loss of water through branchial epithelial surfaces, supplementing the anti-desiccating property of the dried mucus. Upon arousal, it was essential for the lungfish to restore branchial functions. Indeed, the protein abundance of Aqp1 recovered partially, with complete recovery of mRNA expression level and protein abundance of Aqp3, in the gills of P. annectens after 3 days of arousal. These results provide insights
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Directory of Open Access Journals (Sweden)
You R Chng
Full Text Available African lungfishes are ammonotelic in water. They can aestivate for long periods on land during drought. During aestivation, the gills are covered with dried mucus and ammonia excretion ceases. In fishes, ammonia excretion through the gills involves Rhesus glycoproteins (RhGP/Rhgp. This study aimed to obtain the complete cDNA coding sequences of rhgp from the gills of Protopterus annectens, and to determine their branchial mRNA and protein expression levels during the induction, maintenance and arousal phases of aestivation. Three isoforms of rhgp (rhag, rhbg and rhcg were obtained in the gills of P. annectens. Their complete cDNA coding sequences ranged between 1311 and 1398 bp, coding for 436 to 465 amino acids with estimated molecular masses between 46.8 and 50.9 kDa. Dendrogramic analyses indicated that Rhag was grouped closer to fishes, while Rhbg and Rhcg were grouped closer to tetrapods. During the induction phase, the protein abundance of Rhag, but not its transcript level, was down-regulated in the gills, suggesting that there could be a decrease in the release of ammonia from the erythrocytes to the plasma. Furthermore, the branchial transcript levels of rhbg and rhcg decreased significantly, in preparation for the subsequent shutdown of gill functions. During the maintenance phase, the branchial expression levels of rhag/Rhag, rhbg/Rhbg and rhcg/Rhcg decreased significantly, indicating that their transcription and translation were down-regulated. This could be part of an overall mechanism to shut down branchial functions and save metabolic energy used for transcription and translation. It could also be regarded as an adaptive response to stop ammonia excretion. During the arousal phase, it is essential for the lungfish to regain the ability to excrete ammonia. Indeed, the protein abundance of Rhag, Rhbg and Rhcg recovered to the corresponding control levels after 1 day or 3 days of recovery from 6 months of aestivation.
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Winne, Christopher T; Willson, John D; Gibbons, J Whitfield
2006-11-01
1. Capital breeding is an ideal reproductive strategy for many ectotherms because it provides a disassociation between feeding and reproduction, a necessary requirement for animals that become anorexic during pregnancy. Among ectotherms, some viviparous snakes (e.g. Viperidae) exemplify the capital breeding strategy because many species (i) do not feed during pregnancy due to behavioural conflicts between reproduction and foraging, and (ii) take more than one season to accumulate sufficient energetic stores for reproduction. 2. Isolated wetlands often exhibit extreme annual fluctuations in environmental conditions with prolonged droughts periodically leaving wetlands completely dry and devoid of prey. Following droughts, however, wetlands can be extremely productive, rendering prey resources virtually unlimited for some species. 3. This study examines drought survival strategy and reproductive ecology of a small aquatic snake Seminatrix pygaea (Cope) in an isolated wetland. Seminatrix pygaea are atypical from most sympatric snake species in that (i) their small body size, reliance on aquatic prey, and high rates of evaporative water loss make them ill-suited to overland movement, and (ii) they may not be subject to costs typically associated with feeding during pregnancy. 4. We hypothesized that S. pygaea would survive periodic multiyear droughts by aestivating within the dried wetland, a survival strategy heretofore undocumented in snakes. Further, we hypothesized that if S. pygaea rely on 'typical' snake reproductive strategies of 'adaptive anorexia' and capital breeding, reproductive output would be reduced in the first wet year following drought. 5. By encircling a 10-ha wetland with a continuous drift fence before it refilled we were able to demonstrate that S. pygaea were present within the dried wetland prior to the onset of spring rains that refilled the wetland in 2003. Our results suggest that S. pygaea are capable of surviving multiyear droughts by
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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.
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Directory of Open Access Journals (Sweden)
G. Moraes
2005-05-01
Full Text Available Metabolic changes, principally in intermediary metabolism and nitrogen excretion, were investigated in the marble swamp eel (Synbranchus marmoratus after 15 and 45 days of artificially induced semi-aestivation. Glucose, glycogen, lactate, pyruvate, free amino acids, triglycerides, ammonia, urea, and urate contents were determined in liver, kidney, white muscle, heart, brain, and plasma. Lactate dehydrogenase, glutamate dehydrogenase, malate dehydrogenase, aspartate amino transferase, alanine amino transferase, glutamine synthase, ornithine carbamoyl transferase, and arginase enzymes were assayed. The teleost S. marmoratus maintained initial energetic demands by lipid oxidation. The course of normal oxidative processes was observed through tissue enzyme profiles. After the lipid stores were exhausted, the fish consumed body proteins. Constant values of hematocrit during induced semi-aestivation suggested that the water balance remained normal. Therefore, the surrounding water was probably did not trigger the semi-aestivation in this teleost. Decrease of ammonia and increase of renal urea synthesis after 45 days of semi-aestivation led to the assumption that an alternative form of eliminating ammonia exists. Metabolic changes entailed by starvation were proposed to explain the biosynthesis of small molecules involved in the semi-aestivation of S. marmoratus.Foram investigadas variações metabólicas em muçum (Synbranchus marmoratus após 15 e 45 dias de semi-estivação artificial induzida, com ênfase no metabolismo intermediário e excreção de nitrogênio. Glicose, glicogênio, lactato, piruvato, aminoácidos livres, triglicerídios, amônia, uréia e uratos foram determinados em fígado, rim, músculo branco, coração, cérebro, e plasma. As enzimas lactato desidrogenase, glutamato desidrogenase, malato desidrogenase, aspartato amino transferase, alanina amino transferase, glutamina sintetase, ornitina carbamil transferase e arginase foram
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Du, Rongbin; Zang, Yuanqi; Tian, Xiangli; Dong, Shuanglin
2013-03-01
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 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°C. 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 of A. japonicus is complex and may not be attributed to the elevated temperature only.
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A Role For Ca 2+ in the Thermal and Urea Denaturation of ...
African Journals Online (AJOL)
Giant African snail (Achatina achatina) becomes dormant (aestivate) under harsh environmental conditions like dry seasons. During this period the animal accumulates urea and is faced with thermal death. The stability towards thermal and urea denaturation of haemocyanin from aestivating and nonaestivating A. achatina ...
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Cartledge, Victoria A; Withers, Philip C; McMaster, Kellie A; Thompson, Graham G; Bradshaw, S Don
2006-09-01
Burrowed aestivating frogs of the cocoon-forming species Neobatrachus aquilonius and the non-cocooning species Notaden nichollsi were excavated in the Gibson Desert of central Australia. Their hydration state (osmotic pressure of the plasma and urine) was compared to the moisture content and water potential of the surrounding soil. The non-cocooning N. nichollsi was consistently found in sand dunes. While this sand had favourable water potential properties for buried frogs, the considerable spatial and temporal variation in sand moisture meant that frogs were not always in positive water balance with respect to the surrounding soil. The cocoon-forming N. aquilonius was excavated from two distinct habitat types, a claypan in which frogs had a well-formed cocoon and a dune swale where frogs did not have a cocoon. Cocoons of excavated frogs ranged in thickness from 19.4 microm to 55.61 microm and consisted of 81-229 layers. Cocooned claypan N. aquilonius were nearing exhaustion of their bladder water reserves and had a urine osmolality approaching that of the plasma. By contrast, non-cocooned N. aquilonius from the dune swale were fully hydrated, although soil moisture levels were not as high as calculated to be necessary to maintain water balance. Both species had similar plasma arginine vasotocin (AVT) concentrations ranging from 9.4 to 164 pg ml(-1), except for one cocooned N. aquilonius with a higher concentration of 394 pg ml(-1). For both species, AVT showed no relationship with plasma osmolality over the lower range of plasma osmolalities but was appreciably increased at the highest osmolality recorded. This study provides the first evidence that cocoon formation following burrowing is not obligatory in species that are capable of doing so, but that cocoon formation occurs when soil water conditions are more desiccating than for non-cocooned frogs.
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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.
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THE ASIATIC SPECIES OF LINDENBERGIA Lehm. (Scrophulariaceae
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B. PRIJANTO*
1969-03-01
Full Text Available Lindenbergia is represented in Asia by 7 species. Based on the hairiness oftheir ovaries L. muraria (Roxb. Briihl (= L. urticifolia Lehm. and L. indica(L. Vatke (= L. polyantha Benth. are reinstated as distinct species. I followBentham in including Lindenbergia in the tribe Gratioleae.Objection to the use of the aestivation of corolla as the only positivecharacter for distinguishing subfamilies of the Scrophulariaceae is put forward;it is shown that several genera (Lindenbergia, Isoplexis, Lagotis, Erinus, Frey-linia,, Phygelius and Mimulus considered to belong to one subfamily actuallyhave the aestivation character of the other subfamily.The occurrence of resupinatton of the flower in Dopatrium juncewm (Roxb.Buch.-Ham. ex Benth. is recorded for the first time.
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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.
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2013-11-14
... aestivate (sleep during the summer) when they are metabolically stressed or when the weather is cold (Harlow...; 355,000 ac (144,000 ha) in New Mexico; and 100,000 ac (41,000 ha) in Utah (Bureau of Sport Fisheries...
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African Journals Online (AJOL)
Profile of metabolite and biomolecule concentrations in the hemolymph of Bulinus globosus and Bulinus rohlfsi under aestivation and starvation. Abstract · Vol 32, No 2 (2011) - Articles Comparative Studies of two Fresh Water Snail Distributions and Physico-Chemical Parameters in Selected Human Schistosomiasis ...
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Burrow systems of mole-rats as refuges for frogs in the Miombo woodlands of south-east Africa
Czech Academy of Sciences Publication Activity Database
Šklíba, J.; Jirků, Miloslav; Šumbera, R.
2016-01-01
Roč. 32, MAR (2016), s. 158-161 ISSN 0266-4674 R&D Projects: GA ČR GB14-36098G Institutional support: RVO:60077344 Keywords : aestivation * Anura * Bathyergidae * commensalism * ecosystem engineer * Malawi * subterranean rodent * Zambia Subject RIV: EG - Zoology Impact factor: 1.041, year: 2016
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Observations of cocooned Hydrobaenus (Diptera: Chironomidae) larvae in Lake Michigan
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.
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Samanta, Luna; Paital, Biswaranjan
2016-11-01
Natural population of Bufo melanostictus in response to environmental cues shows several physiologic changes such as reproductive activity, hibernation, aestivation and metabolic depression in different seasons. We investigated the effects of seasonal fluctuations on oxidative stress (OS) physiology biomarkers, such as endogenous (ELPx) and induced (ILPx) lipid peroxidation, front-line redox regulatory enzymes (superoxide dismutase: SOD and catalase) and two non-enzyme antioxidant metabolites (ascorbic acid and reduced glutathione) in liver, gonad and cerebral hemisphere of toads collected from the Bhubaneswar area of India, where temperature fluctuates considerably rising to the highest in summer (∼46 °C) and being lowest in winter (pollutants alone and/or as results of metabolic changes under hibernation, aestivation and due to reproductive activities. Therefore, seasonal changes in OS physiological responses in poikilothermic models especially in toads must be cautiously used as indicators to assess environmental impact, mainly soil pollution. Results of the present study may be used as baseline data for any future analyses of the physiological impacts of environmental changes using toads as model organism.
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3.10. Habitat restoration and creation
2016-01-01
1.12.1 Terrestrial habitat Based on the collated evidence, what is the current assessment of the effectiveness of interventions for terrestrial habitat restoration and creation? Beneficial ● Replant vegetation Likely to be beneficial ● Clear vegetation● Create artificial hibernacula or aestivation sites● Create refuges● Restore habitat connectivity Unknown effectiveness (limited evidence) ● Change mowing regime No evidence found (no assessment) ● Create habitat connectivity Beneficial Repla...
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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.
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DAYA MAKAN, DIAPAUSE DAN MOBILITAS KEONG MAS (POMACEA CANALICULATA PADA BERBAGAI KEDALAMAN AIR
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Jacqualine Arriani Bunga
2017-04-01
Full Text Available Feeding rate, aestivation and mobility of golden snails (Pomacea canaliculata at different depths of water. The research was studied in Malaka District, East Nusa Tenggara Province, during the dry and the rainy season (October 2014 - March 2015. Studies on capacity of damage to the Ciherang rice seedlings were carried out for three weeks. The size of snails used in this experiment was 11-20; 21-30; and 31-40 mm. The numbers of seedlings that were planted were 3, 6, 9, 12, 15, 18 and 21 seeds. The treatments were repeated 5 times. The numbers of seeds which are damaged by the snails then were tabulated and analyzed. Snails with the size of 11-20 mm damaged the seeds in 31.67%, followed by snails with the size of 21-30 mm and 31- 40 mm with potency of damaging were 64.76% and 97.38%, respectively. The size of snails affects the level of damage to rice seedlings when transplanting. Study about aestivation was conducted in five villages, namely Kamanasa, Wehali, Umakatahan, Harekakae and Kletek when the rice fields were fallow. The observation point was observed at the corner of the dike and along the dike, evaluated every 10 meters away. The results showed snails aestivate when the fields were dry. Studies on snail’s mobility conducted on the experiment arena on the mud in buckets, which planted with 20 paddy seedlings. The treatment depth of puddles in the experiment were without puddles, half, the same height and twice the height of snails shell. The treatments were repeated 10 times. Measurement of snail’s mobility was performed routinely every 2 hours, observed from the beginning when the snails were placed for 24 hours in advance. The results showed that the depth of the water significantly affected the mobility of snails. Without puddles, the mobility of snails was severely hampered in the mud. The mobility of the juvenile was significantly higher than the imago. The implication of this study was benefit to that the regulating the level
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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.
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Biochemical evaluation of aestivation and starvation in two snail ...
African Journals Online (AJOL)
hope&shola
2010-11-08
Nov 8, 2010 ... ned by drying up of surface water from fresh water bodies either regularly in ... transferases; LDL, low-density lipoprotein; BUN, blood urea nitrogen; UUN ..... white spot syndrome virus infection in penaeus monodon (fabricius).
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Huixia Du
Full Text Available BACKGROUND: Sea cucumbers are a special group of marine invertebrates. They occupy a taxonomic position that is believed to be important for understanding the origin and evolution of deuterostomes. Some of them such as Apostichopus japonicus represent commercially important aquaculture species in Asian countries. Many efforts have been devoted to increasing the number of expressed sequence tags (ESTs for A. japonicus, but a comprehensive characterization of its transcriptome remains lacking. Here, we performed the large-scale transcriptome profiling and characterization by pyrosequencing diverse cDNA libraries from A. japonicus. RESULTS: In total, 1,061,078 reads were obtained by 454 sequencing of eight cDNA libraries representing different developmental stages and adult tissues in A. japonicus. These reads were assembled into 29,666 isotigs, which were further clustered into 21,071 isogroups. Nearly 40% of the isogroups showed significant matches to known proteins based on sequence similarity. Gene ontology (GO and KEGG pathway analyses recovered diverse biological functions and processes. Candidate genes that were potentially involved in aestivation were identified. Transcriptome comparison with the sea urchin Strongylocentrotus purpuratus revealed similar patterns of GO term representation. In addition, 4,882 putative orthologous genes were identified, of which 202 were not present in the non-echinoderm organisms. More than 700 simple sequence repeats (SSRs and 54,000 single nucleotide polymorphisms (SNPs were detected in the A. japonicus transcriptome. CONCLUSION: Pyrosequencing was proven to be efficient in rapidly identifying a large set of genes for the sea cucumber A. japonicus. Through the large-scale transcriptome sequencing as well as public EST data integration, we performed a comprehensive characterization of the A. japonicus transcriptome and identified candidate aestivation-related genes. A large number of potential genetic
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Marta Luciane Fischer
2009-09-01
Full Text Available Achatina fulica Bowdich, 1822 is an african snail that is invasive in different parts of the world, being characterized mainly by its high adaptability. Our objective was to evaluate the influence of abiotic factors, such as temperature and substrate, on the egg eclosion, adult and juvenile reaction to different abiotics factors, and the resistance of A. fulica to popular methods of control. Three studies were made, including 19 laboratory experiments and observations of free animals in the municipal district of Guaraqueçaba, southern Brazil. Eggs were characterized as the most fragile phase, whereas the juveniles and adults were resistant to the immersion in fresh and salt water and little resistant to temperature variation and salt, using burying, aestivation, and muscular force as defense strategies. Those strategies should be considered in management actions and in orientating popular methods of control.
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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.
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Chainy, Gagan Bihari Nityananda; Paital, Biswaranjan; Dandapat, Jagneswar
2016-01-01
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.
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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.
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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.
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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.
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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
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Greater reproductive investment, but shorter lifespan, in agrosystem than in natural-habitat toads
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Francisco Javier Zamora-Camacho
2017-09-01
Full Text Available Global amphibian decline is due to several factors: habitat loss, anthropization, pollution, emerging diseases, and global warming. Amphibians, with complex life cycles, are particularly susceptible to habitat alterations, and their survival may be impaired in anthropized habitats. Increased mortality is a well-known consequence of anthropization. Life-history theory predicts higher reproductive investment when mortality is increased. In this work, we compared age, body size, and different indicators of reproductive investment, as well as prey availability, in natterjack toads (Epidalea calamita from agrosystems and adjacent natural pine groves in Southwestern Spain. Mean age was lower in agrosystems than in pine groves, possibly as a consequence of increased mortality due to agrosystem environmental stressors. Remarkably, agrosystem toads were larger despite being younger, suggesting accelerated growth rate. Although we detected no differences in prey availability between habitats, artificial irrigation could shorten aestivation in agrosystems, thus increasing energy trade. Moreover, agrosystem toads exhibited increased indicators of reproductive investment. In the light of life-history theory, agrosystem toads might compensate for lesser reproductive events—due to shorter lives—with a higher reproductive investment in each attempt. Our results show that agrosystems may alter demography, which may have complex consequences on both individual fitness and population stability.
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MAR YVONNE CHARRIER
2006-01-01
Full Text Available The intestinal microbiota of the edible snails Cornu aspersum fSyn: H. aspersa, and Helix pomatia were investigated by culture-based methods, 16S rRNA sequence analyses and phenotypic characterisations. The study was carried out on aestivating snails and two populations of H. pomatia were considered. The cultivable bacteria dominated in the distal part of the intestine, with up to 5.10(9 CFU g -1, but the Swedish H. pomatia appeared significantly less colonised, suggesting a higher sensitivity of its microbiota to climatic change. All the strains, but one, shared ≥ 97% sequence identity with reference strains. They were arranged into two taxa: the Gamma Proteobacteria with Buttiauxella, Citrobacter, Enterobacter, Kluyvera, Obesumbacterium, Raoultella and the Firmicutes with Enterococcus, Lactococcus, and Clostridium. According to the literature, these genera are mostly assigned to enteric environments or to phyllosphere, data in favour of culturing snails in contact with soil and plants. None of the strains were able to digest filter paper, Avicel cellulose or carboxymethyl cellulose (CMC. Acetogens and methanogenic archaea were not cultivated, so the fate of hydrogen remains questionable. This microbiota could play important roles in the digestive process (fermentation and the energy supply of the snail (L-lactate, acetate. The choice of cereals and plants by snail farmers should take into account the fermentative abilities of the intestinal microbiota
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Acierno, Mark J; Mitchell, Mark A; Roundtree, Marlana K; Zachariah, Trevor T
2006-12-01
To determine whether there are increased concentrations of 25-hydroxyvitaminn D(3) in red-eared slider turtles (Trachemys scripta elegans) after exposure to UV radiation. 12 yearling turtles recently removed from aestivation. Turtles were randomly allocated to 2 groups (6 turtles/group). An initial blood sample was collected from all turtles for measurement of 25-hydroxyvitamin D(3) concentrations. Turtles of 1 group were then provided no supplemental lighting, whereas turtles of the other group were exposed to full-spectrum coil bulbs at a distance of 22.86 cm. The UV-A and UV-B radiation generated by the supplemental lighting was measured by use of a radiometer-photometer at weekly intervals. Measurements were collected 2.54 and 22.86 cm from the bulb surface. The study was continued for a 4-week period. At the end of the study, a second blood sample was collected from all turtles for measurement of 25-hydroxyvitamin D(3). Mean +/- SD 25-hydroxyvitamin D(3) concentrations differed significantly between turtles provided supplemental UV radiation (71.7 +/- 46.9 nmol/L) and those not provided UV radiation (31.4 +/- 13.2 nmol/L). Appropriate husbandry recommendations for raising and maintaining red-eared slider turtles should include use of sunlight that is unobstructed by UV-B filtering material or provision of an artificial source of UV-B radiation.
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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.
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Spiral phyllotaxis underlies constrained variation in Anemone (Ranunculaceae) tepal arrangement.
Kitazawa, Miho S; Fujimoto, Koichi
2018-05-01
Stabilization and variation of floral structures are indispensable for plant reproduction and evolution; however, the developmental mechanism regulating their structural robustness is largely unknown. To investigate this mechanism, we examined positional arrangement (aestivation) of excessively produced perianth organs (tepals) of six- and seven-tepaled (lobed) flowers in six Anemone species (Ranunculaceae). We found that the tepal arrangement that occurred in nature varied intraspecifically between spiral and whorled arrangements. Moreover, among the studied species, variation was commonly limited to three types, including whorls, despite five geometrically possible arrangements in six-tepaled flowers and two types among six possibilities in seven-tepaled flowers. A spiral arrangement, on the other hand, was unique to five-tepaled flowers. A spiral phyllotaxis model with stochasticity on initiating excessive primordia accounted for these limited variations in arrangement in cases when the divergence angle between preexisting primordia was less than 144°. Moreover, interspecific differences in the frequency of the observed arrangements were explained by the change of model parameters that represent meristematic growth and differential organ growth. These findings suggest that the phyllotaxis parameters are responsible for not only intraspecific stability but interspecific difference of floral structure. Decreasing arrangements from six-tepaled to seven-tepaled Anemone flowers demonstrate that the stabilization occurs as development proceeds to increase the component (organ) number, in contrast from the intuition that the variation will be larger due to increasing number of possible states (arrangements).
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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.
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Gavira, Rodrigo S B; Sartori, Marina R; Gontero-Fourcade, Manuel N; Gomes, Bruna F; Abe, Augusto S; Andrade, Denis V
2018-04-19
Tegu lizards ( Salvator merianae ) aestivate for up to 5 months during Brazil's winter, when they retreat to burrows and halt most activities. Dormant tegus reduce their gastrointestinal (GI) mass, which allows a substantial energy economy. This strategy, however, implies that the first post-dormancy digestion would be more costly than subsequent feeding episodes as a result of GI atrophy. To address this, we determined the postprandial metabolic response (SDA) of the first (M1), second (M2) and several (RM) feeding episodes after tegus' dormancy. Another group of tegus (PF) was subjected to an extra 50 day fasting period after arousal. Glucose, triglycerides and uric acid levels were checked before and after feeding. M1 digestion lasted twice as long and cost twofold more when compared with M2 or RM, in agreement with the idea that GI atrophy inflates digestion cost at the first post-dormancy meal. The SDA response was similar in M2 and RM, suggesting that the GI tract was fully reorganized after the first feeding. The SDA cost was equal in PF and RM, implying that the change in state per se (dormant to arousal) triggers the regrowth of GI, independently of feeding. Fasting tegus at M1 presented higher triglyceride and lower uric acid levels than fed tegus, indicating that fasting is mainly sustained by fat storage. Our results show that seasonal fasting imposes an extra digestion cost to tegus following their next feeding, which is fully paid during their first digestion. This surplus cost, however, is negligible compared with the overall energetic savings from GI tract atrophy during the dormancy period. © 2018. Published by The Company of Biologists Ltd.
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Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes.
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
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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.
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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
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Directory of Open Access Journals (Sweden)
Zaidett Barrientos
2000-03-01
Full Text Available The introduced snail Ovachlamys fulgens (Stylommatophora: Helicarionidae occurs on cultivated land habitats in Costa Rica, where its macrodistribution seems to be limited by annual mean temperature (20 - 27.6°C and annual precipitation (1 530 - 3 034 and 3 420 - 8 000 mm, with no more than six dry months. This species can be found in litter and on vegetation up to 70 cm tall. Random quadrat field sampling was done in leaf litter and understory plants every three months for a total of five dates in Central Costa Rica. At least 150 plots of 25x25 cm were analyzed on each date. Abundance of living specimens and eggs was positively correlated with (1 litter abundance and depth, (2 litter and soil humidity, (3 relative humidity and (4 early morning temperature (6:30 AM, and negatively correlated with temperature later in the morning (10:00 AM. Besides these factors, living snail abundance was correlated with thickness of the herbaceous vegetation and with the occurrence of Yucca elephantiphes (in litter and understory. Egg abundance was also correlated with the sampling date, apparently because of changes in humidity. The correlation pattern of shell abundance was opposite to that of living specimens. Population size and number of empty shells throughout the year parallel the rainfall pattern. Reproduction takes place between May and November (wet season; and up to 92% of the specimens can be found aestivating between December and April (dry season. Clutch size averages three eggs. The maximum density of living specimens was reached in December (43.41 ind/m² and the minimum in March (8.30 ind/m². Shells decompose in an average of five months.El caracol introducido Ovachlamys fulgens (Stylommatophora: Helicarionidae habita regiones cultivadas de Costa Rica y su distribución está limitada por temperaturas anuales entre 20 y 27.6ºC y precipitaciones anuales entre 1530-3034 y 3420-8000 mm con no más de seis meses secos. Esta especie habita en la
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Medem Fred
1958-09-01
the Amazon. In Venezuela he ranges as far as San Fernando de Atabapo in the upper Orinoco area. For unexplainable reasons he does not enter the Amazon, by the comunicatron of the Orinoco-Casiquiare-Río Negro. 7. Numerous ecological observations were made on habitat, size, alimentation, parasites, reproduction and behavior. The "record" in size is apparently shown by an old male, which, according to Humboldt was 22 feet 3 inches long (6.78 meters. As far as known the females do not grow larger than 4 to 4.50 meters. The 4 fetus were between 22.4 cm. and 23.7 cm. long. The food of intermedius consists mainly of fish: in the stomach specimens a great amount of small stones were found ranging from 440 gr. to 920 gr. The egg laying period takes place mainly in January and the juveniles hatch in March. The eggs are white; their average size is about 8 em. long and 5 cm. wide. Up to 70 eggs were found in a nest. March 3, 1957 a nest 43 cm. deep and 51 cm. wide at the base, was found in the Río Guaviare. It was situated on a, sand-bank, about 40 meters from the river. The first eggs were found in a depth of 27 cm. The temperature in the nest, measured before the eggs were taken out, was slightly higher than outside. The shell of the eggs was quite elastic while still in the nest, but became hard soon after being taken out. Of the 57 eggs found in the nest, 54 contained fetus, the remaining 3 were rotten. The fetus already moved; but still had a well developed vitelline sack. The female, a specimen a about 3 meters long, remained in the water, splashing furiously. Cr. intermedius undergoes an aestivation the dry season in the Llanos Orientales (Rivers Arauca, Meta, Vichada but no information is available from the Guaviare area. The Orinoco Crocodile of the Guaviare area digs no subterranean caves as does Cr. acutus from the Magdalena region and other rivers of northern Colombia. Due to excessive