Sea cucumber Apostichopus japonicus is an ideal model organism for marine invertebrate aestivation;it annually enters a“sleeping state”for nearly 3 months when ambient water temperature range is 25–30℃.The natural...Sea cucumber Apostichopus japonicus is an ideal model organism for marine invertebrate aestivation;it annually enters a“sleeping state”for nearly 3 months when ambient water temperature range is 25–30℃.The natural fasting is accompanied by remodeling the intestinal biota and function,which is a part of host biology and could affect the gut microbiota.We investigatesd the impact of annual aestivation on gut microbiota using high-throughput sequencing of 16S rRNA amplicons.Results reveal a notable alteration in the composition of gut bacteria during aestivation during which various indigenous families and genera that exhibit a preference for dietary glycans(e.g.,family Rhodobacteraceae and Flavobacteriaceae)decreased,while the taxa capable of utilizing substrates derived from the host(e.g.,genus Akkermansia and Prevotella)increased,and so did certain opportunistic pathogenic bacteria.Moreover,the investigation delved into the gut morphology and immunity response of A.japonicus and reveal that the intestine of A.japonicus undergoes substantial atrophy and degeneration during aestivation.However,there was an observed augmentation in the levels of acid and neutral mucin within mucous cells,as well as an enhanced immune defense response(as evidenced by increased gene expression of AjTLR3,LITAF,Ajp105,and LYZ).These results imply that the composition of sea cucumber gut microbiota differed between aestivation and active periods,which potentially affects the intestinal functions of the host and the symbiotic relationship between host and its microbiota over the activeaestivation cycle.展开更多
The effect of water temperature on gut mass and digestive enzyme activity in sea cucumber Apostichopusjaponicus, including relative gut mass （RGM）, amylase, lipase, pepsin and trypsin activities were studied at temp...The effect of water temperature on gut mass and digestive enzyme activity in sea cucumber Apostichopusjaponicus, including relative gut mass （RGM）, amylase, lipase, pepsin and trypsin activities were studied at temperatures of 7, 14, 21, and 28℃ over a period of 40 days. Results show that RGM significantly decreased after 40 days at 21 ℃ and markedly decreased over the whole experiment period at 28℃; however, no significant effect of duration was observed at 7 or 14℃. At 14℃, trypsin activity significantly decreased over 10 and 20 days, then increased; amylase and trypsin activity significantly decreased after 40 days at 28℃. However, no significant effect of duration was found on amylase, pepsin or trypsin activities in the other temperature treatment groups. At 28℃, 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℃ continuously increased over the whole experimental period. Principle component analysis showed that sea cucumbers on day 40 in the 21℃ group and in the previous 20 days in the 28℃ group were in the prophase of aestivation. At 28℃, sea cucumbers aestivated at 30-40 days after the start of the experiment. It is concluded that the effect of temperature on the digestion ofA. 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.展开更多
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. ...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 l, 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.展开更多
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 ...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 （RPSI 8）, 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] 1α 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.展开更多
Aestivation is a common strategy of sea cucumbers(Apostichopus japonicus)in response to high-temperature conditions.Previous studies have individually investigated the immune and physiological alterations at the aesti...Aestivation is a common strategy of sea cucumbers(Apostichopus japonicus)in response to high-temperature conditions.Previous studies have individually investigated the immune and physiological alterations at the aestivation stage.However,these studies have not evaluated the relationship between immunity and physiology.In this study,we explored the transcriptome and metabolome of A.japonicus during the aestivation stage to study the relationship.The transcriptome analysis of dormant(aestivation)and revived A.japonicus generated 2368 differentially expressed genes,including 927 downregulated genes and 1441 upregulated genes.Based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses,the downregulated genes in the dormant group were found to be involved in DNA replication,RNA metabolic process,and protein metabolism,which results in the inhibition of motility,skeletal development,neural activity,cell proliferation,and development of A.japonicus.In contrast,the upregulated genes were found to be associated with fatty acid metabolism,carbohydrate hydrolysis,and phagocytosis.In the metabolome analysis,the downregulated metabolites were found to be associated with fatty acid metabolism,starch and sucrose metabolism,and TCA cycle.This indicates that dormant sea cucumbers consume reserved carbohydrates and fatty acids to maintain low levels of energy supply.The protein-protein interaction network analysis further revealed that carbohydrate hydrolysis promoted phagocytosis activity in the dormant group.This study provides new insights into potential molecular mechanisms of sea cucumber survival in high-temperature conditions,which is critical in aquaculture of sea cucumbers.展开更多
Dormancy represents a fascinating adaptive strategy for organisms to survive in unforgiving environments.After a period of dormancy,organisms often exhibit exceptional resilience.This period is typically divided into ...Dormancy represents a fascinating adaptive strategy for organisms to survive in unforgiving environments.After a period of dormancy,organisms often exhibit exceptional resilience.This period is typically divided into hibernation and aestivation based on seasonal patterns.However,the mechanisms by which organisms adapt to their environments during dormancy,as well as the potential relationships between different states of dormancy,deserve further exploration.Here,we selected Perccottus glenii and Protopterus annectens as the primary subjects to study hibernation and aestivation,respectively.Based on histological and transcriptomic analysis of multiple organs,we discovered that dormancy involved a coordinated functional response across organs.Enrichment analyses revealed noteworthy disparities between the two dormant species in their responses to extreme temperatures.Notably,similarities in gene expression patterns pertaining to energy metabolism,neural activity,and biosynthesis were noted during hibernation,suggesting a potential correlation between hibernation and aestivation.To further explore the relationship between these two phenomena,we analyzed other dormancy-capable species using data from publicly available databases.This comparative analysis revealed that most orthologous genes involved in metabolism,cell proliferation,and neural function exhibited consistent expression patterns during dormancy,indicating that the observed similarity between hibernation and aestivation may be attributable to convergent evolution.In conclusion,this study enhances our comprehension of the dormancy phenomenon and offers new insights into the molecular mechanisms underpinning vertebrate dormancy.展开更多
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 phosp...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 of A. japonicus is complex and may not be attributed to the elevated temperature only.展开更多
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...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.展开更多
This study aims to examine the following three hypotheses on the impact of global warming on the populations of the water strider, Aquarius paludum in the Kochi-Nankoku area (33。30'N) of Kochi prefecture, Japan t...This study aims to examine the following three hypotheses on the impact of global warming on the populations of the water strider, Aquarius paludum in the Kochi-Nankoku area (33。30'N) of Kochi prefecture, Japan through the recent data collected in 2009-2011. 1) Has the generation number increased? 2) Has aestivation appeared in adults? 3) Have overwintering adults stopped dispersing between the water surface and overwintering lands-sites far away from water and, instead, overwintered on/near the shore? Sampling data showed that the number of generations may have increased from three (1989-2002 strains) and four (2004-2008) to five (2009-2011) per year in Kochi (33。N). The ratio of adults having well developed flight muscles decreased from 45% in 1995 to 24% - 28% in 2009-2011 inoverwintering adults collected from the field in fall likely as a result of histolysis. “Mosaic-typed” wing morph group with long fore-wings and short hind-wings newly appeared in 2009-2011 in the Kochi-Nankoku overwintering populations. The mosaic-typed wings group cannot fly and the black and long fore wings might function as absorbing apparatus of sun-lights in the daytime of winter. Some overwintering adults seem to stop migrating between water bodies and overwintering sites on land far from the water bodies and overwinter, instead, near the shore. The use of Aquarius paludum as a biological indicator would be possible in the future, because this species can respond and change their reproductive and dispersal characteristics to the global change.展开更多
Invasive alien species are one of the greatest threats to biodiversity and ecosystem globally,affecting delivery of ecosystem goods and services,and consequently human well-being.Oreochromis niloticus is one of the mo...Invasive alien species are one of the greatest threats to biodiversity and ecosystem globally,affecting delivery of ecosystem goods and services,and consequently human well-being.Oreochromis niloticus is one of the most highly successful invaders of aquatic ecosystems with competitive characteristic advantages over indigenous species.The aim of this study was to investigate the potential presence and impact of O.niloticus on Mitukutuku fishery.The study was undertaken using fisheries independent surveys for the period of 2 months.Fish identification key and gel electrophoresis identification methods were also used to confirm presence of O.niloticus and also possible hybridization with indigenous congeneric species.Fisheries dependent survey was conducted with fishers and traders to further assess presence of the invasive species and its impacts on their catches and socio-economic well-being.A total of 32 Oreochromis hybrids species and 19 of O.niloticus were found in the reservoir.This confirmed a higher proportion of O.niloticus in the reservoir.Results from interviews of fishers and traders revealed catch per unit effort of O.hybrids and O.niloticus to be higher compared to that of indigenous congeneric species.Similarly,fish traders confirmed that income for the fish sales increased from 5%in March to 7%in August.Overall,these results suggested that O.niloticus does not only exist in Mitukutuku reservoir,but also hybridizes with native species and dominates the entire stretch of the reservoir threatening loss of biodiversity and aquaculture breeding programme.There is need for restricting culture of O.niloticus in Zambia.展开更多
The non-marine strata of the Ypresian Naredi Formation have been deposited and intermittently pedogenized after the culmination of the Early Eocene Climatic Optimum(EECO).This continental interval comprises intercalat...The non-marine strata of the Ypresian Naredi Formation have been deposited and intermittently pedogenized after the culmination of the Early Eocene Climatic Optimum(EECO).This continental interval comprises intercalation of laterite and palaeosol horizons developed by cyclic episodes of erosion,subaerial exposure,and deposition.The palaeopedological analyses investigate the morphological and micromorphological features evidencing repeated subaerial exposure and consequently moderate to well-developed palaeosol horizons.The topmost laterite bed records an intensely bioturbated ichnofabric(consisting of the root traces and the composite ichnotaxa of lungfish aestivation burrows,Macanopsis(possible arachnid burrows),and Skolithos.The pedogenized shale horizons contain the paucispecific Camborygma-root trace ichnofabric with highly localized patchy preservation of Camborygma symplokonomos,Camborygma eumekenomos,and rhizoturbation.The ichnospecies variation of Camborygma along with the ichnofabric analyses led to the demarcation of stratigraphic horizons and evaluation of the palaeowater-table fluctuations vis-a-vis the low-order allocyclicity,the ethology of producers,and the depositional setting.The paucispecific suite of trace fossils refers to the Camborygma Ichnofacies,where the substrate is intermittently pedogenized and lateritized with upward increasing thickness of beds and intensity of pedogenesis,lateritization,ichnodiversity,and ichnoabundance.Hence,as an expression of high-frequency(interpreted as 5th-order)stratigraphic fluctuations within an early Falling Stage Systems Tract(FSST),a hot palaeoclimate with seasonality varying between humid inundated to dry desiccated conditions is interpreted with the palaeowater table being the base-level control.It culminates with the driest condition at the top with the thickest laterite development associated with the RAeMaS ichnofabric.With the onset of early transgression as documented in the overlying marine deposits of the Bartonian Harudi Formation,the top of the studied interval marks an induced subaerial unconformity.展开更多
Organisms often live in unpredictable environments and have to adopt life history strategies that optimize their fitness under these conditions.According to bet-hedging theory,individuals can reduce variation in fitne...Organisms often live in unpredictable environments and have to adopt life history strategies that optimize their fitness under these conditions.According to bet-hedging theory,individuals can reduce variation in fitness outcomes by investing in different strategies at the same time.For arthropods,facultative summer diapause enables survival during dry and hot periods of the year,and can be triggered by a decrease in resource abundance. However,the effect of resource depletion on diapause induction has never been disentangled from the effect of the perception of the presence of competitors.Using two solitary parasitoid species of cereal aphids as a model system,Aphidius avenae (Haliday)and Aphidius rhopalosiphi (De Stefani-Perez)(Hymenoptera:Braconidae),we tested whether (i)low absolute host density and/or (ii)high levels of parasitoid females'competition lead to maternal-induced summer diapause in parasitoid offspring.Under summer-like climatic conditions,emerging parasitoid females were (i)reared alone and exposed to different host densities (from 5 to 130 aphids),or (ii)reared together with competing females (from 2 to 20 females)and then exposed individually to 50 aphids.For both parasitoid species, low aphid densities did not induce summer diapause.However,the incidence of summer diapause increased up to a maximum of 11% with increasing levels of competition expe rienced by female parasitoids.More than 60% of the females produced both diapausing and nondiapausing offspring after being kept at the two highest competition densities. Such a "spreading-the-risk"strategy has likely evolved to optimize parasitoid fitness by preventing the following generation from exposure to low populations of suitable hosts and high mortality from superparasitism.These results provide the first experimental evidence of direct maternal competition-induced diapause in insects,and may change the way we apprehend the evolution of arthropod seasonal ecology,by considering intraspecific competition.展开更多
基金Supported by the National Natural Science Foundation of China(No.41906098)the NSFC-Shandong Joint Fund(No.U2106208)the Development Plan of Youth Innovation Team in Colleges and Universities of Shandong Province(No.2022KJ269)。
文摘Sea cucumber Apostichopus japonicus is an ideal model organism for marine invertebrate aestivation;it annually enters a“sleeping state”for nearly 3 months when ambient water temperature range is 25–30℃.The natural fasting is accompanied by remodeling the intestinal biota and function,which is a part of host biology and could affect the gut microbiota.We investigatesd the impact of annual aestivation on gut microbiota using high-throughput sequencing of 16S rRNA amplicons.Results reveal a notable alteration in the composition of gut bacteria during aestivation during which various indigenous families and genera that exhibit a preference for dietary glycans(e.g.,family Rhodobacteraceae and Flavobacteriaceae)decreased,while the taxa capable of utilizing substrates derived from the host(e.g.,genus Akkermansia and Prevotella)increased,and so did certain opportunistic pathogenic bacteria.Moreover,the investigation delved into the gut morphology and immunity response of A.japonicus and reveal that the intestine of A.japonicus undergoes substantial atrophy and degeneration during aestivation.However,there was an observed augmentation in the levels of acid and neutral mucin within mucous cells,as well as an enhanced immune defense response(as evidenced by increased gene expression of AjTLR3,LITAF,Ajp105,and LYZ).These results imply that the composition of sea cucumber gut microbiota differed between aestivation and active periods,which potentially affects the intestinal functions of the host and the symbiotic relationship between host and its microbiota over the activeaestivation cycle.
基金Supported by the Science Fund for Creative Research Groups (No.40821004)National Natural Science Foundation of China (No.40576073)+1 种基金Breeding Project of Shandong Province (China),National Key Technology Research and Development Program of China (No. 2006BAD09A02)the National High Technology Research and Development Program of China (863 Program) (No.2006AA100304 /2006AA10A411)
文摘The effect of water temperature on gut mass and digestive enzyme activity in sea cucumber Apostichopusjaponicus, including relative gut mass （RGM）, amylase, lipase, pepsin and trypsin activities were studied at temperatures of 7, 14, 21, and 28℃ over a period of 40 days. Results show that RGM significantly decreased after 40 days at 21 ℃ and markedly decreased over the whole experiment period at 28℃; however, no significant effect of duration was observed at 7 or 14℃. At 14℃, trypsin activity significantly decreased over 10 and 20 days, then increased; amylase and trypsin activity significantly decreased after 40 days at 28℃. However, no significant effect of duration was found on amylase, pepsin or trypsin activities in the other temperature treatment groups. At 28℃, 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℃ continuously increased over the whole experimental period. Principle component analysis showed that sea cucumbers on day 40 in the 21℃ group and in the previous 20 days in the 28℃ group were in the prophase of aestivation. At 28℃, sea cucumbers aestivated at 30-40 days after the start of the experiment. It is concluded that the effect of temperature on the digestion ofA. 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.
基金Supported by the National Key Technology Research and Development Program(No.2006AA10A411)the Agricultural Seed Project of Shandong Province
文摘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 l, 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.
基金Supported by the National Nature Science Foundation of China(Nos.41176139,31201972)
文摘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 （RPSI 8）, 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] 1α 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.
基金supported by the Science and Technology Program of Fujian Province(Nos.2018R1003-1 and 2019R1013-5)the Special Funds for Marine and Fishery Structure Adjustment(No.2020HYJG02)the Marine Economy Innovation and Area Development Demonstration Project of Fujian Province(No.FJHJF-L-2020-4)。
文摘Aestivation is a common strategy of sea cucumbers(Apostichopus japonicus)in response to high-temperature conditions.Previous studies have individually investigated the immune and physiological alterations at the aestivation stage.However,these studies have not evaluated the relationship between immunity and physiology.In this study,we explored the transcriptome and metabolome of A.japonicus during the aestivation stage to study the relationship.The transcriptome analysis of dormant(aestivation)and revived A.japonicus generated 2368 differentially expressed genes,including 927 downregulated genes and 1441 upregulated genes.Based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses,the downregulated genes in the dormant group were found to be involved in DNA replication,RNA metabolic process,and protein metabolism,which results in the inhibition of motility,skeletal development,neural activity,cell proliferation,and development of A.japonicus.In contrast,the upregulated genes were found to be associated with fatty acid metabolism,carbohydrate hydrolysis,and phagocytosis.In the metabolome analysis,the downregulated metabolites were found to be associated with fatty acid metabolism,starch and sucrose metabolism,and TCA cycle.This indicates that dormant sea cucumbers consume reserved carbohydrates and fatty acids to maintain low levels of energy supply.The protein-protein interaction network analysis further revealed that carbohydrate hydrolysis promoted phagocytosis activity in the dormant group.This study provides new insights into potential molecular mechanisms of sea cucumber survival in high-temperature conditions,which is critical in aquaculture of sea cucumbers.
基金supported by the National Natural Science Foundation of China (32170480,31972866)Youth Innovation Promotion Association,Chinese Academy of Sciences (http://www.yicas.cn)+1 种基金Young Top-notch Talent Cultivation Program of Hubei ProvinceWuhan Branch,Supercomputing Center,Chinese Academy of Sciences,China。
文摘Dormancy represents a fascinating adaptive strategy for organisms to survive in unforgiving environments.After a period of dormancy,organisms often exhibit exceptional resilience.This period is typically divided into hibernation and aestivation based on seasonal patterns.However,the mechanisms by which organisms adapt to their environments during dormancy,as well as the potential relationships between different states of dormancy,deserve further exploration.Here,we selected Perccottus glenii and Protopterus annectens as the primary subjects to study hibernation and aestivation,respectively.Based on histological and transcriptomic analysis of multiple organs,we discovered that dormancy involved a coordinated functional response across organs.Enrichment analyses revealed noteworthy disparities between the two dormant species in their responses to extreme temperatures.Notably,similarities in gene expression patterns pertaining to energy metabolism,neural activity,and biosynthesis were noted during hibernation,suggesting a potential correlation between hibernation and aestivation.To further explore the relationship between these two phenomena,we analyzed other dormancy-capable species using data from publicly available databases.This comparative analysis revealed that most orthologous genes involved in metabolism,cell proliferation,and neural function exhibited consistent expression patterns during dormancy,indicating that the observed similarity between hibernation and aestivation may be attributable to convergent evolution.In conclusion,this study enhances our comprehension of the dormancy phenomenon and offers new insights into the molecular mechanisms underpinning vertebrate dormancy.
基金supported by the Natural Science Funds for Distinguished Young Scientists of Shandong Province (No.JQ201009)the National Great Project of Scientific and Technical Supporting Programs (No.2011-BAD13B03)+2 种基金the National Natural Science Foundation of China (No.30771661)the Public Science and Technology Research Funds Projects of Ocean, State Oceanic Administration of China (No.200905020)the 111 Project of China Ministry of Education (No.B08049)
文摘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 of A. japonicus is complex and may not be attributed to the elevated temperature only.
基金Supported by the National Marine Public Welfare Research Project(No.201305043)the National Natural Science Foundation of China(No.41106134)the National Key Technology R&D Program of China(Nos.2011BAD13B02,2010BAC68B01)
文摘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.
文摘This study aims to examine the following three hypotheses on the impact of global warming on the populations of the water strider, Aquarius paludum in the Kochi-Nankoku area (33。30'N) of Kochi prefecture, Japan through the recent data collected in 2009-2011. 1) Has the generation number increased? 2) Has aestivation appeared in adults? 3) Have overwintering adults stopped dispersing between the water surface and overwintering lands-sites far away from water and, instead, overwintered on/near the shore? Sampling data showed that the number of generations may have increased from three (1989-2002 strains) and four (2004-2008) to five (2009-2011) per year in Kochi (33。N). The ratio of adults having well developed flight muscles decreased from 45% in 1995 to 24% - 28% in 2009-2011 inoverwintering adults collected from the field in fall likely as a result of histolysis. “Mosaic-typed” wing morph group with long fore-wings and short hind-wings newly appeared in 2009-2011 in the Kochi-Nankoku overwintering populations. The mosaic-typed wings group cannot fly and the black and long fore wings might function as absorbing apparatus of sun-lights in the daytime of winter. Some overwintering adults seem to stop migrating between water bodies and overwintering sites on land far from the water bodies and overwinter, instead, near the shore. The use of Aquarius paludum as a biological indicator would be possible in the future, because this species can respond and change their reproductive and dispersal characteristics to the global change.
文摘Invasive alien species are one of the greatest threats to biodiversity and ecosystem globally,affecting delivery of ecosystem goods and services,and consequently human well-being.Oreochromis niloticus is one of the most highly successful invaders of aquatic ecosystems with competitive characteristic advantages over indigenous species.The aim of this study was to investigate the potential presence and impact of O.niloticus on Mitukutuku fishery.The study was undertaken using fisheries independent surveys for the period of 2 months.Fish identification key and gel electrophoresis identification methods were also used to confirm presence of O.niloticus and also possible hybridization with indigenous congeneric species.Fisheries dependent survey was conducted with fishers and traders to further assess presence of the invasive species and its impacts on their catches and socio-economic well-being.A total of 32 Oreochromis hybrids species and 19 of O.niloticus were found in the reservoir.This confirmed a higher proportion of O.niloticus in the reservoir.Results from interviews of fishers and traders revealed catch per unit effort of O.hybrids and O.niloticus to be higher compared to that of indigenous congeneric species.Similarly,fish traders confirmed that income for the fish sales increased from 5%in March to 7%in August.Overall,these results suggested that O.niloticus does not only exist in Mitukutuku reservoir,but also hybridizes with native species and dominates the entire stretch of the reservoir threatening loss of biodiversity and aquaculture breeding programme.There is need for restricting culture of O.niloticus in Zambia.
基金Science and Engineering Research Board(SERB),Government of India(grant#CRG/2018/000259 to SDG)Industrial Research and Consultancy Centre(IRCC),IIT Bombay(seed grant#RD/0517-IRCCSH0-035 to SDG and final-year scholarship to MD)+1 种基金IITB and Ministry of Education,Government of India(doctoral scholarship for MD)Council of Scientific&Industrial Research(CSIR)(doctoral scholarship for RD.
文摘The non-marine strata of the Ypresian Naredi Formation have been deposited and intermittently pedogenized after the culmination of the Early Eocene Climatic Optimum(EECO).This continental interval comprises intercalation of laterite and palaeosol horizons developed by cyclic episodes of erosion,subaerial exposure,and deposition.The palaeopedological analyses investigate the morphological and micromorphological features evidencing repeated subaerial exposure and consequently moderate to well-developed palaeosol horizons.The topmost laterite bed records an intensely bioturbated ichnofabric(consisting of the root traces and the composite ichnotaxa of lungfish aestivation burrows,Macanopsis(possible arachnid burrows),and Skolithos.The pedogenized shale horizons contain the paucispecific Camborygma-root trace ichnofabric with highly localized patchy preservation of Camborygma symplokonomos,Camborygma eumekenomos,and rhizoturbation.The ichnospecies variation of Camborygma along with the ichnofabric analyses led to the demarcation of stratigraphic horizons and evaluation of the palaeowater-table fluctuations vis-a-vis the low-order allocyclicity,the ethology of producers,and the depositional setting.The paucispecific suite of trace fossils refers to the Camborygma Ichnofacies,where the substrate is intermittently pedogenized and lateritized with upward increasing thickness of beds and intensity of pedogenesis,lateritization,ichnodiversity,and ichnoabundance.Hence,as an expression of high-frequency(interpreted as 5th-order)stratigraphic fluctuations within an early Falling Stage Systems Tract(FSST),a hot palaeoclimate with seasonality varying between humid inundated to dry desiccated conditions is interpreted with the palaeowater table being the base-level control.It culminates with the driest condition at the top with the thickest laterite development associated with the RAeMaS ichnofabric.With the onset of early transgression as documented in the overlying marine deposits of the Bartonian Harudi Formation,the top of the studied interval marks an induced subaerial unconformity.
文摘Organisms often live in unpredictable environments and have to adopt life history strategies that optimize their fitness under these conditions.According to bet-hedging theory,individuals can reduce variation in fitness outcomes by investing in different strategies at the same time.For arthropods,facultative summer diapause enables survival during dry and hot periods of the year,and can be triggered by a decrease in resource abundance. However,the effect of resource depletion on diapause induction has never been disentangled from the effect of the perception of the presence of competitors.Using two solitary parasitoid species of cereal aphids as a model system,Aphidius avenae (Haliday)and Aphidius rhopalosiphi (De Stefani-Perez)(Hymenoptera:Braconidae),we tested whether (i)low absolute host density and/or (ii)high levels of parasitoid females'competition lead to maternal-induced summer diapause in parasitoid offspring.Under summer-like climatic conditions,emerging parasitoid females were (i)reared alone and exposed to different host densities (from 5 to 130 aphids),or (ii)reared together with competing females (from 2 to 20 females)and then exposed individually to 50 aphids.For both parasitoid species, low aphid densities did not induce summer diapause.However,the incidence of summer diapause increased up to a maximum of 11% with increasing levels of competition expe rienced by female parasitoids.More than 60% of the females produced both diapausing and nondiapausing offspring after being kept at the two highest competition densities. Such a "spreading-the-risk"strategy has likely evolved to optimize parasitoid fitness by preventing the following generation from exposure to low populations of suitable hosts and high mortality from superparasitism.These results provide the first experimental evidence of direct maternal competition-induced diapause in insects,and may change the way we apprehend the evolution of arthropod seasonal ecology,by considering intraspecific competition.
