latridius is a genus of beetles in the family latridiidae , containing the following species : latridius amplus johnson , 1977 latridius assimilis ( mannerheim , 1844 ) latridius brevicollis ( thomson , 1868 ) latridius canariensis ( palm , 1972 ) latridius consimilis ( mannerheim , 1844 ) latridius crenatus ( le conte , 1855 ) latridius desertus ( fall , 1899 ) latridius gemellatus ( mannerheim , 1844 ) latridius hirtus gyllenhal , 1827 latridius minutus ( linnaeus , 1767 ) latridius mongolicus rücker , 1983 latridius nigritus ( fall , 1899 ) latridius peacockae ( sen gupta , 1976 ) latridius perminutus johnson , 1977 latridius reflexus ( leconte , 1855 ) latridius porcatus ( herbst , 1793 ) latridius protensicollis mannerheim , 1843

latridius

из позднеэоценового ровенского янтаря описан latridius usovae sergi et perkovsky , sp . n . новый вид отличается от latridius alexeevi bukejs , kirejtshuk et rucker , 2011 и l . jantaricus borowiec , 1985 из балтийского янтаря формой переднеспинки , надкрыльев , средних и задних голеней .
johnson , c . , rucker , w . h . latridius regalis spec . nov . , eine neue art der gattung latridius ( coleoptera ) aus osterreich / / latridiidae - mitteilungsblatt fur systematik und taxonomie der latridiidae - 2011 . - 8 . - s . 21 - 23 .
based on a fossil specimen from late eocene rovno amber , latridius usovae sergi et perkovsky , sp . n . is described . it differs from latridius alexeevi bukejs , kirejtshuk et rucker , 2011 and l . jantaricus borowiec , 1985 ( both described from baltic amber ) by the shape of pronotum , elytra , mid and hind tibiae .
bukejs , a . , kirejtshuk , a . g . , rucker , w . h . new species of latridius ( coleoptera : latridiidae ) from baltic amber / / baltic journal of coleopterology . - 2011 . - 11 , n 2 . - p . 203 - 207 .
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native to palaearctic , adventive in the new world ; in our area , across so . canada and the us ( nf - ak to md - la - tx & co - ca )
the most common latridiid associated with stored products ( incl . grains ) ; especially frequent in putrid , mouldy vegetables and decaying hay / grass ; in buildings , hymenoptera nests , bird nests , manure heaps , decomposing fungi , wood stacks , on various mouldy objects ; native habitats ( e . g . , coniferous forests ) ; has been reared from dead conifer wood
beetles associated with stored products in canada : an identification guide bousquet y . 1990 . research branch agriculture canada , publication 1837 .
latridiidae ( coleoptera ) of atlantic canada : new records , keys to identification , new synonyms , distribution , and zoogeography majka c . g . , langor d . , rücker w . h . 2009 . the canadian entomologist 141 : 317 - 370 .
herbst in jablonsky , 1793 . accessed at : urltoken ; = 989870 on 2018 - 07 - 09
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full reference : j . f . w . herbst . 1793 . natursystem aller bekannten in - und ausländischen insekten als eine fortsezzung der von büffonschen naturgeschichte . der käfer fünfter theil 1 - 392
parent taxon : latridiinae according to h . p . reike et al . 2017
see also bouchard et al . 2011 , hawkeswood et al . 2009 , herbst 1793 , lesne 1920 , reike et al . 2013 and sergi and perkovsky 2014
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2 schmalhausen institute of zoology , nas of ukraine , vul . b . khmelnytskogo , 15 , kyiv , 01601 ukraine
borowiec , l . two new species of lathridius sensu lato ( coleoptera : lathridiidae ) from baltic amber / / polskie pismo entomologiczne . - 1985 . - 55 . - p . 251 - 254 .
dudka , i . o . , trikchleb , t . a . , romanenko , k . o . associations of myxomycetes with coleoptera ( latridiidae ) / / ecology and noospherology . - 2002 . - 12 , n 3 - 4 . - p . 54 - 64 . - ukrainian : дудка і . о . , трихліб т . а . , романенко к . о . асоціації міксоміцетів з жуками - скритниками ( coleoptera , latridiidae ) .
fall , h . c . revision of the lathridiidae of boreal america / / transactions of the american entomological society . - 1899 . - 26 . - p . 101 - 190 + pls . 3 - 5 .
johnson , c . latridiidae / / catalogue of palaearctic coleoptera / eds . i . lobl , a . smetana . - stenstrup : apollo books , 2007 . - vol . 4 . elateroidea , derodontoidea , bostrichoidea , lymexyloidea , cleroidea , cucujoidea . - p . 635 - 648 . `
hatch , m . h . th e beetles of the pacifi c northwest . part iii . pselaphidae and diversicornia i . - seattle : university of washington press , 1962 . - 503 p .
hinton , h . e . th e lathridiidae of economic importance / / bulletin of entomological research . - 1941 . - 32 . - p . 191 - 247 .
krasutsky , b . v . mycetophilous beetles of ural and trans - ural . vol . 2 . fungus - insect system . - chelyabinsk : ural section of the russian entomological society , 2005 . - 213 p . - russian : красуцкий б . в .
perkovsky , e . e . , zosimovich , v . yu . , vlaskin , a . p . a rovno amber fauna : a preliminary report / / acta zool . cracov . - 2003 . - 46 ( suppl . - fossil insects ) . - p . 423 - 430 .
perkovsky , e . e . , zosimovich , v . yu . , vlaskin , a . p . rovno amber in biodiversity of fossils in amber from the major world deposits / ed . d . penney . - manchester : siri scientifi c press , 2010 . - р . 116 - 136 .
rucker , w . h . kulonboző csapu bogarak vi ( diversicornia vi ) . bunkoscsapu bogarak vii ( clavicornia vii ) : merophysiidae , latridiidae , dasyceridae / / magyarorszag allatvilaga ( fauna hungariae ; n 158 ) . - budapest : akademiai kiado , 1983 . - 68 p .
rucker , w . h . checklist latridiidae & merophysiinae of the world / / latridiidae & merophysiinae . - 2010 . - 9 . - s . 1 - 16 .
cite score 2016 : 0 . 35 scimago journal rank ( sjr ) 2016 : 0 . 300 source normalized impact per paper ( snip ) 2016 : 0 . 496
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apostichopus japonicus is a species of sea cucumber in the family stichopodidae .

it is found in shallow temperate waters along the coasts of south east asia and is commonly known as the japanese spiky sea cucumber or the japanese sea cucumber .

apostichopus japonicus

frédéric ducarme marked
file : japan sea animal , apostichopus japonicus . jpg
as trusted on the
apostichopus japonicus
page .
draft genome of the sea cucumber apostichopus japonicus and genetic polymorphism among color variants .
figure 5 : related data from apostichopus japonicus individual levels after each gene silencing .
print version : sea cucumber apostichopus japonicus . ( 9780127999531 / 0127999531 / 900827492 )
figure 4 : related data from apostichopus japonicus primary cultured coelomocytes after each gene silencing .
draft genome of the sea cucumber apostichopus japonicus and genetic polymorphism among color variants . - pubmed - ncbi
expression analysis of immune related genes identified from the coelomocytes of sea cucumber ( apostichopus japonicus ) in response to lps challenge .
expression analysis of immune related genes identified from the coelomocytes of sea cucumber ( apostichopus japonicus ) in response to lps challenge . - pubmed - ncbi
gigadb dataset - doi 10 . 5524 / 100257 - supporting data for
draft genome of the sea cucumber apostichopus japonicus and genetic polymorphis . . .
distribution of the japanese sea cucumber apostichopus japonicus in the intertidal zone of hirao bay , eastern yamaguchi pref . , japan : suitable environmental factors for juvenile habitats
distribution of the japanese sea cucumber apostichopus japonicus in the intertidal zone of hirao bay , eastern yamaguchi pref . , japan : suitable environmental factors for juvenile habitats
distribution of the japanese sea cucumber apostichopus japonicus in the intertidal zone of hirao bay , eastern yamaguchi pref . , japan : suitable environmental factors for juvenile habitats [ 2006 ]
zhang b l , sun d y , wu y q . 1995 . preliminary analysis on the feeding habit of apostichopus japonicus in the rocky coast waters of lingshan island .
bogatyrenko , e . a . , buzoleva , l . s . , and chi , z . , potential probiotics of the far eastern trepang apostichopus japonicus producing digestive enzymes ,
zhang w j , hou h m , zhang g l , li q y , du c m . 2011 . study on diversity of intestine cultivable microorganisms from apostichopus japonicus .
lebedev , a . m . 2000 . fisheries and reserves of the far eastern sea cucumber apostichopus japonicus . russina journal of marine biology 26 ( 4 ) : 296 - 302 .
22 . 6 . problems and prospects in sustainable a . japonicus production in japan
apostichopus japonicus appears to be more tolerant to environmental fluctuations than many other species of sea cucumbers . however , the larval stages remain rather sensitive and less tolerant to variations in their environment .
three color variants of a . japonicus ( green , red , and black ) .
12 . 5 . differences in mitf gene expressions in albino and normal a . japonicus
12 . 6 . differences in astacin gene expressions in albino and normal a . japonicus
gao f , sun h l , xu q , tan j , yan j p , wang q y . 2010 . pcrdgge analysis of bacterial community composition in the gut contents of apostichopus japonicus .
zhang x c , nakahara t , murase s , nakata h , inoue t , kudo t . 2013 . physiological characterization of aerobic culturable bacteria in the intestine of the sea cucumber apostichopus japonicus .
today , in northern china , the sea cucumber apostichopus japonicus is commonly farmed in earth ponds either in an extensive or semi - intensive system . sea rafts are sometimes used , but are not very popular .
selin , n . i . 2001 . vertical distribution of the far east trepang apostichopus japonicus in vostok bay , sea of japan . russian journal of marine biology 27 ( 4 ) : 256 - 258 .
12 . 3 . differences in nutrient and melanin contents between albino and normal a . japonicus
12 . 4 . differences in histological and ultrastructural characteristics between albino and normal a . japonicus
yang z p , sun f x , liu z m , zhang l , cao w , ma y x . 2013 . screening and identification of potential enzyme producing probiotics from gut of sea cucumber apostichopus japonicus .
17 . 3 . bioremediation capability of a . japonicus when combined with bivalve and / or macroalgae
gao f , li f h , tan j , yan j p , sun h l . 2014 . bacterial community composition in the gut content and ambient sediment of sea cucumber apostichopus japonicus revealed by 16s rrna gene pyrosequencing .
li b , rong x j , liao m j , chen g p , zhang z , wang y g , xue t s . 2010 . bacteria community in the intestine and culture environment of apostichopus japonicus in winter .
− 1 d − 1 ) of apostichopus japonicus during the experimental period . means ( n = 4 ) with different letters denoting significant differences ( p < 0 . 05 ) , and bars representing standard deviations of the means .
chen , l . , li , q . and yang , j . 2008 . microsatellite genetic variation in wild and hatchery populations of the sea cucumber ( apostichopus japonicus selenka ) from northern china . aquaculture research 2008 : 1 - 9 .
dubrovskii , s . v . and sergeenko , v . a . 2002 . distribution pattern of far eastern sea cucumber apostichopus japonicus in busse lagoon ( southern sakhalin ) . russian journal of marine biology 28 ( 2 ) : 87 - 93 .
in northern inshore areas of china , many other animals inhabit the eelgrass ecosystems in which a . japonicus is abundant . this study showed that decaying eelgrass debris could act as an important food resource for a . japonicus .
kanno , m . , suyama , y . , li , q . & kijima , a . 2006 . microsatellite analysis of japanese sea cucumber , stichopus ( apostichopus ) japonicus , supports reproductive isolation in color variants . marine biotechnology , 8 : 672 - 685 .
zhao y c , zhang w b , xu w , mai k s , zhang y j , liufu z g . 2012 . effects of potential probiotic bacillus subtilis t13 on growth , immunity and disease resistance against vibrio splendidus infection in juvenile sea cucumber apostichopus japonicus .
citation : du h , bao z , hou r , wang s , su h , yan j , et al . ( 2012 ) transcriptome sequencing and characterization for the sea cucumber apostichopus japonicus ( selenka , 1867 ) . plos one 7 ( 3 ) : e33311 . urltoken
wang , p . , chang , y . , yu , j . , li , c . & xu g . 2007 . acute peristome edema disease in juvenile and adult sea cucumbers apostichopus japonicus ( selenka ) reared in north china . journal of invertebrate pathology 96 : 11 - 17 .
dong , y . , dong , s . , tian , x . , wang , f . & zhang , m . 2006 . effects of diel temperature fluctuations on growth , oxygen consumption and proximate body composition in the sea cucumber apostichopus japonicus selenka . aquaculture , 255 : 514 - 521 .
dong , s . , liang , m . , gao , q . , wang , f . , dong , y . & tian , x . 2010 . intra - specific effects of sea cucumber ( apostichopus japonicus ) with reference to stocking density and body size . aquaculture research , 41 : 1170 - 1178
cheon s ; cho sj ; hong hh ; jin s ; jo j ; kern ema ; lee hg ; lee sg ; oh j ; park c ; park jk ( 2016 ) : supporting data for
draft genome of the sea cucumber apostichopus japonicus and genetic polymorphism among color variants
gigascience database . urltoken
lysenko , v . n . , zharikov , v . v . , and lebedev , a . m . , the abundance and distribution of the japanese sea cucumber , apostichopus japonicus ( selenka , 1867 ) ( echinodermata : stichopodidae ) , in nearshore waters of the southern part of the far eastern state marine reserve ,
citation : liu x , zhou y , yang h , ru s ( 2013 ) eelgrass detritus as a food source for the sea cucumber apostichopus japonicus selenka ( echinidermata : holothuroidea ) in coastal waters of north china : an experimental study in flow - through systems . plos one 8 ( 3 ) : e58293 . urltoken
there are over 1 000 species of sea cucumbers known worldwide . more than 100 species can be found in china , amongst which more than 20 species are considered edible . most of them , e . g . thelenota ananas , stichopus chloronotus , s . variegatus and apostichopus japonicus , are distributed in the southern sea of china .
yuan , x . , yang , h . , wang , l . , zhou , y . , zhang , t . and liu , y . 2007 . effects of aestivation on the energy budget of sea cucumber apostichopus japonicus ( selenka ) ( echinodermata : holothuroidea ) . acta ecologica sinica 27 ( 8 ) : 3155 - 3161 .
zzd is one of the main aquaculture and fishery companies in china , and it is the biggest base for aquaculture and sea ranching of high - valued seafood in north yellow sea . it operates a 2000 km 2 ocean farm , producing about 60 thousand t of scallop patinopecten yessoensis , sea cucumber apostichopus japonicus and abalone haliotis discus hannai annually .
sang , c . 1963 . biology of japanese common sea cucumber , stichopus japonicus selenka . kaibundo , tokyo , japan ( in japanese with english summary )
the yield and growth condition of albino juveniles and thermal resistant juveniles was checked by experts . after the project leader reported the work statement , the experts inquired the key technology and the progress of the project and finally confirmed the achievement on artificial breeding of thermal resistant a . japonicus and albino a . japonicus . according to the results of the project , the thermal resistant strain could terminate the stage of estivation 17 days earlier than normal a . japonicus . furthermore , the thermal resistant strain could endure 1 degree higher temperature than normal a . japonicus . the results of gene expression of heat shock proteins and lethal high temperature test indicated that the thermal resistant strain had better thermostability . at present , the yield of thermal resistant a . japonicus was one million eight hundred thousand , which included eight hundred thousand f1 offspring and one million f2 offspring . in addition , 18 a . japonicus pedigrees were established and each pedigree had 5000 - 30000 individuals . in march 2010 , the artificial breeding of albino a . japonicus was carried out . up to october 2010 , the yield of albino offspring was one million three hundres thousand .
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 markers were also identified from the a . japonicus transcriptome . this transcriptome resource would lay an important foundation for future genetic or genomic studies on this species .
some researchers pointed out that the appropriate temperature for the growth of a . japonicus is 5–20°c , while the optimum is 10–16°c [ 40 ] – [ 42 ] . during the experiment , the water temperature ranged from 13 . 5–20 . 8°c ( fig . 2 ) . with an increase in water temperature to 18°c , a . japonicus gradually went into an aestivation state , and the fpr of a . japonicus reduced rapidly ( fig . 2 ) . before entering into aestivation , the fpr of a . japonicus was higher , which were 0 . 33 g·ind . −1 d −1 , 1 . 31 g·ind . −1 d −1 , 1 . 31 g·ind . −1 d −1 , 0 . 63 g·ind . −1 d −1 for treatments es10 , es20 , es40 , and es100 , respectively ( fig . 3 ) . according to the experiment the water temperature had an effect on the sgr and fpr of a . japonicus which fed on the mixed food containing eelgrass detritus and seafloor surface sediment . when the water temperature was between 13 and 17°c , a . japonicus grew faster .
yaqing , c . , changging y . & songxin . 2004 . pond culture of sea cucumbers , apostichopus japonicus , in dalian . in : a lovatelli , c . conand , s . purcell , s . uthicke , j - f . hamel & a . mercier ( eds ) , advances in sea cucumber aquaculture and management , pp . 269 - 272 . fao fisheries technical paper no 463 . fao , rome .
jo , j . , oh , j . , lee , h . - g . , hong , h . - h . , lee , s . - g . , cheon , s . , … park , c . ( 2017 ) . draft genome of the sea cucumber apostichopus japonicus and genetic polymorphism among color variants . gigascience , 6 ( 1 ) , 1–6 . doi : 10 . 1093 / gigascience / giw006
publication date 2015 series developments in aquaculture and fisheries science ; volume 39 note includes index . available in another form print version : sea cucumber apostichopus japonicus : history , biology and aquaculture . london , england : academic press , ©2015 xxiii , 454 pages developments in aquaculture and fisheries science ; volume 39 ( 9780127999531 ) isbn 0127999531 ( trade cloth ) 9780127999531 ( trade cloth ) 9780128004678 ( e - book ) 0128004673 ( e - book ) 9780127999531
in order to verify which factors affect habitat selection for aestivating and in the active adult apostichopus japonicus , animals were tested for their selection of attachment site in an experimental device ( 1 - m pipes ) in which the perceived environmental stimuli ( light intensity , degree of contact with a hard surface , geotaxis ) varied depending on the attachment site . during the aestivating season , the animals showed a strong selection for attachment sites during the daytime and nighttime ; they also showed positive stereotaxis ( thigmotaxis ) , negative phototaxis , and negative geotaxis . the results suggest that ( 1 ) habitats are not suitable for the aestivating adult a . japonicus unless these three environmental requirements are satisfied .
to identify genomic repeat elements in the a . japonicus genome assembly , we ran repeatmasker ( version 4 . 0 . 6 ) [ 19 ] using the repbase transposable element library ( release 20150807 ) [ 20 ] and the de novo repeat library constructed by repeatmodeler ( version 1 . 0 . 8 ) [ 21 ] . approximately 27 . 2 % of the a . japonicus genome was identified as interspersed repeats .
generally , a . japonicus feeds on sediments containing organic matter , which includes microorganisms and the detritus of plants or animals . results in this experiment showed that a . japonicus could use eelgrass detritus as a food resource . according to the present study , a mixture of z . marina debris and seafloor muddy sediments with an organic content of 19 . 6 % ( es40 ) , could lead to a better growth effect .
the collecting of the decaying eelgrass leaves and the invertebrate apostichopus japonicus from swan lake of weihai was permitted by peiliang wang , manager of mashan group co . ltd . no specific permit was required for the collecting of the sediment from jiaozhou bay , qingdao , where is not privately owned or protected . ethical approval was not required for this study because no endangered animals were involved . however , specimen collection and maintenance were performed in strict accordance with the recommendations of animal care quality assurance in china .
recently the institute of oceanology , chinese academy of sciences and shandong oriental ocean sci - tech co . , ltd collaborated on the establishment of sea products breeding and healthy aquaculture lab . these affiliations carried out the research on the breeding of thermal resistant a . japonicus and albino a . japonicus jointly , and finally achieved a series of innovative outcome , which laid the groundwork for popularization and industrialization of thermal resistant strain and albino strain .
according to several sources of information , the output of apostichopus japonicus in dalian was 906 tonnes in 1955 . with the improvement of breeding technology , the quantity of farmed sea cucumbers has increased significantly . in 1999 , the farming area was estimated at around 32 000 hectares and the output at 2 000 tonnes ; the following year , in 2000 , the farming area covered 48 000 hectares , while the output was 3 000 tonnes valued at 200 million yuan . in 2002 , the production reached 8 000 tonnes .
yin - geng , w . , chun - yun , z . , xiao - jun , r . , jie - jun , c . & cheng - yin , s . 2004 . diseases of cultured sea cucumber , apostichopus japonicus , in china in : a lovatelli , c . conand , s . purcell , s . uthicke , j - f . hamel & a . mercier ( eds ) , advances in sea cucumber aquaculture and management , pp . 297 - 310 . fao fisheries technical paper no 463 . fao , rome .
schematic workflow of a . japonicus genome assembly and annotation . the left side represents the genome assembly and the right side represents the transcriptome assembly that was performed in previous publications . to achieve suitable gene prediction , we integrated these two assembly results .
( of stichopus japonicus selenka , 1867 ) selenka , e . ( 1867 ) . beitrage zur anatomie und systematik der holothurien . der philosophischen facultat zu gottingen in december 1866 , als dissertation vorgelegt . : pp . 291 - 374 . [ details ]
the spatial and size - frequency distribution of the japanese sea cucumber , apostichopus japonicus , in the far eastern state marine reserve and unprotected parts of peter the great bay , sea of japan was studied using both scuba diving equipment and a remotely operated underwater sub - fighter 3000 vehicle . the abundance of the japanese sea cucumber and the pattern of its distribution over the southern part of the reserve were determined . it was found that the density of sea cucumber aggregations in the studied unprotected parts of peter the great bay is not lower than that over the major portion of the reserve .
at present , artificial breeding and culture of sea cucumbers is still a work in progress , but the scale of the production is increasing and a number of questions related to the culture techniques are being raised , calling for further studies on the commercial aspects of a . japonicus aquaculture .
figure 1 . the development of a . japonicus . 1 . gastrula ; 2 . early auricularia ; 3 . mid auricularia ; 4 . late auricularia ; 5 . early doliolaria ; 6 . doliolaria ; 7 . early pentactula ; 8 . pentactula ( bar = 100 mm ) .
sgr of a . japonicus in treatment es0 with a negative value was significantly lower than that in other treatments ( all p < 0 . 05 ) ( fig . 1 ) . and sgr of a . japonicus in treatment es40 was significantly higher than those in treatments es10 and es20 ( f = 24 . 08 , df = 7 , p = 0 . 003 ; f = 16 . 57 , df = 7 , p = 0 . 007 , respectively ) . no significant differences were found between the other treatments es10 , es20 and es100 ( all p > 0 . 05 ) .
gut microorganisms play an important role in the digestion of their host animals . the purpose of this research was to isolate and assess the enzyme - producing microbes from the apostichopus japonicus gut . thirty - nine strains that can produce at least one of the three digestive enzymes ( protease , amylase , and cellulase ) were qualitatively screened based on their extracellular enzyme - producing abilities . the enzyme - producing strains clustered into eight groups at the genetic similarity level of 100 % by analyzing the restriction patterns of 16s rdna amplified with mbo i . phylogenetic analysis revealed that 37 strains belonged to the genus bacillus and two were members of the genus virgibacillus . enzyme - producing capability results indicate that the main enzyme - producing microflora in the a . japonicus gut was bacillus , which can produce protease , amylase , and cellulase . virgibacillus , however , can only produce protease . the high enzyme - producing capability of the isolates suggests that the gut microbiota play an important role in the sea cucumber digestive process .
( of stichopus japonicus var . typicus théel , 1886 ) théel , h . ( 1886 ) . report on the holothurioidea dredged by h . m . s . ' challenger ' during the years 1873 - 76 . chall . rep . zool . no . xxxix : 290 pp . [ details ]
at the beginning of the experiment , there were no significant differences in wet body weights of a . japonicus between the five treatments ( f = 1 . 20 , df = 39 , p = 0 . 33 ) ( table 2 ) . by contrast , at the end of the experiment , final wet body weight of a . japonicus in treatment es0 was significantly lower than that in other treatments containing eelgrass debris ( all p < 0 . 05 ) . and final wet body weight in treatment es40 was significantly higher that that in treatments es10 and es20 ( both p < 0 . 05 ) .
the development of a . japonicus includes six major phases : fertilized oocytes , early development ( including cleavage , blastula and gastrula ) , auricularia ( including early auricularia , middle auricularia and late auricularia ) , metamorphosis ( including doliolaria and pentactula ) , juvenile , young sea cucumber and adult ( figure 1 ) .
mixtures of z . marina debris and sediment were used to feed a . japonicus . according to the proportion of z . marina debris , 5 diet treatments in quadruplicate were designed , i . e . , es0 , es10 , es20 , es40 , and es100 , with eelgrass debris accounting for 0 % , 10 % , 20 % , 40 % , and 100 % in dry weight , respectively . the chemical composition of each diet was analyzed in 3 replicates . each diet treatment involved 4 aforementioned pvc boxes , and each box contained 2 individuals of a . japonicus with initial wet body weights of 25 . 12±5 . 79 g·ind . −1 . the experiment was conducted from april 22nd to june 8th , 2009 in the laboratory at the institute of oceanology , chinese academy of sciences , qingdao , p . r . china . during the experiment , specific growth rates and fecal production rates of a . japonicus were measured .
assimilation efficiency ( ae ) of organic matter by a . japonicus had no significant difference in four experimental treatments ( fig . 4 ) , with mean ae being 14 . 2 % , 14 . 3 % , 24 . 2 % , and 21 . 8 % , respectively ( all p > 0 . 05 ) .
although a . japonicus always occurs abundantly in eelgrass - rich meadows in temperate northern coastal areas of china ; yet it has never been reported whether eelgrass detritus can act as a food source for sea cucumbers or not . in this study , decaying eelgrass debris and muddy sediment were mixed as food to feed a . japonicas . the ingestion and growth of the animals were then determined , in order to understand the importance of eelgrass meadows for a . japonicus , and thus clarify the importance of eelgrass - meadow restoration . it is suggested that eelgrass - meadow restoration is imperative and could not only be of huge ecological benefit , but also of potential economic value .
the initial and final wet body weight of a . japonicus was measured . animal feces were collected by siphon every 1–3 days , depending on the amount of produced feces . for estimation of assimilation efficiency ( ae ) of a . japonicus , fresh feces produced within 6 h were collected . fecal samples were dried at 60°c to constant weight and preserved for further analysis . subsamples of the dried food and feces were used to estimate organic material ( om ) by combusting ( 500°c for 3 h ) dried and pre - weighed samples . subsamples were treated with hcl vapor for 6 h to remove carbonates for analyzing organic carbon ( oc ) and nitrogen ( on ) with a perkin elmer model 240c chn analyzer standardized with acetanilide .
in this experiment , the organic contents of food in the five diet treatments were 5 . 6 % , 7 . 6 % , 10 . 9 % , 19 . 6 % , 39 . 9 % , respectively ; and organic matter in the feces of a . japonicus was lower than that in the food ; and organic carbon and nitrogen were the same ( table 1 ) .
in conclusion , a comprehensive collection of ests has been achieved for the sea cucumber a . japonicus using the 454 gs flx platform , permitting gene discovery and characterization across a broad range of functional categories . in addition , our study identified a large number of ssrs and snps , from which genetic markers can be rapidly developed to serve as tools for further genetic or genomic studies on this species .
in comparison with the 454 sequencing data obtained from sun et al . [ 15 ] , 53 % of the hq reads obtained in our study did not find significant matches ( blastn , e < 10 −4 ) with their data . for gene annotation , 94 % of gene annotations obtained in this study were not found in their data . these above results possibly suggest more representative collections of a . japonicus genes in this study .
in this experiment , sgr of a . japonicus in the five treatments were significantly different . sgr was only −0 . 65 % d −1 in the pure sediment diet ( treatment es0 ) , which was significantly lower than that in the mixed diets of z . marina debris and sediment . in contrast , the mean sgr in treatments es10 , es20 , es40 and es100 were 0 . 70 % ·d −1 , 0 . 61 % ·d −1 , 1 . 54 % ·d −1 , and 1 . 20 % ·d −1 , respectively ( fig . 1 ) . the occurrence of negative growth of a . japonicus fed with pure sediment might be due to the lower organic matter content ( 5 . 6 % ) of the diet , which might not satisfy the need for growth . the highest sgr of a . japonicus occurred in treatment es40 with organic matter content being 19 . 6 % and higher than that in es0 , es10 , and es20 ; while in the pure eelgrass - debris diet ( es100 ) with organic matter content as high as 39 . 9 % , the sgr was not significantly higher than that in treatment es40 ( p > 0 . 05 ) . sea cucumbers are deposit feeders , and clay sediment is an important component of ingested material , which is supposed to be helpful for the digestion of food [ 37 ] .
fig . 2 shows variation in fecal production rates ( fpr ; g·ind . −1 d −1 ) of a . japonicus during the experimental period . sea cucumbers in treatment es0 had hardly ingested food during the experiment period , thus only fecal production rates in other treatments were considered comparable with each other . generally , fprs in treatments es20 and es40 were significantly higher than those in treatments es10 and es100 ( all p < 0 . 05 ; fig . 3 ) .
in natural eelgrass ecosystems , deposit feeders feed on organic detritus after eelgrass decomposition , which not only accelerates the cycling of matter but also promotes the health and stability of the ecosystem structure . until now eelgrass meadows in shandong coastal waters with water depth 2–6 m have deteriorated badly , and some eelgrass meadows have even disappeared [ 43 ] . for the restoration of the declining natural resource of a . japonicus , it is suggested that the degraded eelgrass meadows should be restored in the northern inshore areas of china .
with a . japonicus , spawning often occurs between 2100 h and 0200 h . it is important to maintain a quiet environment and keep the tanks in the dark . male sea cucumbers usually are the first to spawn , which in turn induce the females to start releasing the eggs . at this point the number of spawning males should be reduced , only retaining a few strong spawners . following the spawning activity the tanks are drained and all the sea cucumbers removed . the eggs are gently washed and the tanks refilled with clean seawater at a temperature of 22 °c .
to maximize the transcript representation in a broad range of biological processes , eight a . japonicus cdna libraries representing different developmental stages and adult tissues were constructed and used for 454 sequencing ( table 1 ) . after a single - run of 454 sequencing , a total of 1 , 061 , 078 raw reads with an average length of 344 bases were obtained . the size distribution of raw reads is shown in figure 1a . of all these reads , 92 % ( 974 , 004 reads ) passed through our quality filters and represented high - quality ( hq ) reads .
the hq reads combined with the public ests were assembled into 33 , 835 contigs and 199 , 011 singletons . approximately 80 % ( 774 , 993 ) of the hq reads were incorporated into contigs . the size of contigs ranged from 101 to 6 , 323 bp , with an average length of 630 bp . the size distribution of contigs is shown in figure 1b . the sequencing coverage of contigs ranged from 2 to 7 , 429 with a mean of 23 . as expected for a randomly fragmented transcriptome , there was a positive relationship between the length of a given contig and the number of reads assembled into it ( figure 1c ) . contigs were then assembled into 29 , 666 isotigs ranging from 104 to 7 , 697 bp with an average length of 1 , 042 bp ( n50 = 1 , 294 bp ) . the size distribution of isotigs is shown in figure 1d . the average contig coverage for each isotig was 2 . 1 . the isotigs were further grouped into 21 , 071 isogroups , which possibly represents the total number of genes in the a . japonicus transcriptome . the summary statistics for the a . japonicus est assembly are shown in table 2 .
validation of rna - seq results using qrt - pcr . the relative fold changes of 10 genes expressed in a . japonicus coelemocytes at 4 h ( a ) ; 24 h ( b ) and 72 h ( c ) after lps challenge . gene abbreviations are : bf , complement factor b ; c3 - 2 , complement component 3 - 2 ; cat b , cathepsin b ; cd36 , cluster of differentiation 36 ; hsp90 , heat shock protein 90 ; lbp , lipopolysaccharide binding protein ; myd88 , myeloid differentiation primary response gene 88 ; mys , myosin ; rel , nf - κb transcription factor rel ; thy , thymosin β .
eelgrass debris used in this study was from decaying eelgrass leaves . the decaying dark colored eelgrass leaves were collected from swan lake of weihai . muddy sediment was obtained from the non - vegetated seafloor surface in the inshore area of jiaozhou bay , qingdao . both decaying eelgrass leaves and sediment were dried at 65°c , ground and sieved using 0 . 18 mm mesh . the specimens of a . japonicus used in this study were also collected from the cove of swan lake . sea cucumbers were transported to the laboratory where they were acclimatized for a week , after which an experiment was carried out using 20 pvc boxes , with each box measuring 30×40×30 cm in size .
in addition , 52 , 102 high - quality snps and 2 , 083 indels were identified from 10 , 333 contigs ( table 5 ) . the predicted snps included 30 , 366 transitions , 21 , 736 transversions . the overall frequency of all types of snps including indels was one per 393 bp . we randomly chose 32 contigs containing 201 snps to evaluate the preference of snp position in the coding regions . the result showed that 70 % of snps resided in the third codon position , while 18 % and 12 % in the first and second codon position , respectively . experimental validation was also carried out to evaluate the reliability of the predicted snps . fifteen of randomly chosen snps were subject to experimental validation in 48 a . japonicus adults using the high - resolution melting ( hrm ) genotyping method [ 42 ] . it turned out that 80 % of these snps could be validated , suggesting the majority of our predicted snps are likely to be true snps .
the history of sea cucumber fishery dates back for more than 1 000 years . over the last century , and especially the past 20 years , chinese research projects have focused on the breeding , artificial culture and processing of sea cucumber .
after the oocytes have been fertilized , they slowly sink and start their development . when the water temperature ranges from 21 to 24 °c the fertilized eggs require about 45 minutes to begin to divide themselves and finally develop into a blastula ( table 1 ) . the blastula is ciliated and rotates actively . after about 2 to 3 h , the hatched embryo gradually elongates and moves to the surface of the water column . during this ascent the embryo begins to invaginate and gradually develops into gastrula . a fully developed gastrula appears at the surface of the culture tanks 24 to 28 h after fertilization . twelve to twenty hours later the gastrula gradually elongates and begins to fold into the auricularia stage .
1 . water temperature maintained between 21 . 5 and 23 °c . 2 . results obtained in research facilities in yantai and changdao ( china ) and japan .
the auricularia stage lasts from day 7 to day 10 at a water temperature ranging from 18 to 26 °c . early auricularia larvae have a symmetrical bilateral and a length varying from 320 to 600 mm . as the larva grows , the stomach increases in size . when the auricularia reaches 600 to 750 mm , its left cavity , which adjoins the stomach and gullet , begins to grow and gradually takes on a semi circular shape . at this point , the auricularia has reached the middle phase of its development . later , the cilia develop into five pairs of symmetrical circles . at the same time , the primary tentacles begin to develop as the larva reaches the late auricularia stage . typically , the ball shaped body of the larva at this stage is the early sign of the upcoming doliolaria stage .
in the late auricularia phase , the larvae begin to shrink ; the five lipid spheres finally connect while the tentacles enlarge and move to the centre of the body . at this stage the auriculariae are still swimming in the water column ; they move from the surface to the bottom . the settlement plates should be placed in the tanks at this time .
the doliolaria phase usually lasts for 1 or 2 days at the end of which five tentacles reach out of the body . at this moment , the larvae begin to creep along the bottom for an additional 1 or 2 days . the number of cilia on the body surface of the larvae progressively decreases and x - shaped ossicles gradually begin to appear . the body becomes rounder and the first tube - like foot emerges on the left posterior section of the body . the presence of podia is a significant precursor to the juvenile stage .
the primary change in the juvenile stage is the appearance of tube - like feet ( which enables the organism to attach to a substrate ) and the ability to ingest food . the gut , mouth and papillae become clearly visible . in the next couple of months the juvenile sea cucumbers grow to about 1 cm in length assuming the appearance of an adult individual . the body pigmentation changes gradually from a transparent whitish appearance to a red , grey or light green colouration ( figure 2 ) . at this point the individual has reached the young sea cucumber stage .
there is almost no morphological difference between a young and an adult sea cucumber . in a hatchery facility the movement and feeding activity of young sea cucumbers sharply decreases when the seawater temperature exceeds 23 °c . the young specimens move from the surface of the water to the bottom of the tank . for this reason it is important to maintain an optimal temperature level in the culture tanks to ensure adequate growth and reduce the length of this relatively fragile developmental stage .
a large sea cucumber hatchery in northern china typically has the following facilities : a larvae culture volume of 2 600 m 3 divided into tanks of 10 to 20 m 3 with a depth of 1 . 4 m ; a juvenile culture volume of 4 000 m 3 divided into tanks of 30 m 3 with a depth of 1 . 7 m ( figure 3 ) ; a phytoplankton production unit with a total tank volume of 500 m 3 ; 4 filter tanks of 200 m 3 / h filtering capacity ; and 5 overhead troughs of 200 m 3 each . the facility is also fitted with a high quality water supply and drainage system as well as a heater to raise the water temperature when necessary .
the devices used for larval settlement include metal frames each fitted with 5 - 10 polyethylene screens measuring 50 x 50 cm and used as the settlement substrate ( figure 4 ) .
figure 3 . sea cucumber settlement device ( photo : a . lovatelli ) .
figure 4 . sea cucumber hatchery in the vicinity of dalian , liaoning province . juvenile culture tanks ( photo : a . lovatelli ) .
the optimum water temperature in a hatchery is between 23 and 25 °c , even though sea cucumbers can adapt to a range between 10 and 26 °c . the best salinity level is 31 . 6 , but individuals can tolerate salinities from 26 to 33 . the optimal ph is 7 . 8 , but it can range from 7 . 5 to 8 . 2 . the dissolved oxygen should be maintained at > 5 mg / litre .
broodstock harvesting . individuals are generally collected from the 20 th june to the 20 th july in the dalian area . at that time , the seawater temperature varies from 15 to 17 °c . a few individuals are usually sacrificed and dissected in order to adequately determine the maturation stage of the gonads . specimens weighing around 300 g and measuring around 20 cm in length are generally preferred .
considerable care is required during the collection and transportation of the sea cucumber broodstock . it is important to : 1 ) select each specimen individually ; 2 ) keep the selected sea cucumber away from any source of pollution ( e . g . oil spills from the boat engine ) ; 3 ) avoid exposing the sea cucumbers to high temperatures or violent movements during transport ; and 4 ) avoid simultaneous collection of the sea cucumbers and other marine organisms ( e . g . bivalves ) in order to avoid damaging the broodstock .
maintaining broodstock . following collection , the sea cucumbers should be placed in a tank filled with seawater at ambient temperature . the tanks should be clean and the individuals kept at a density of 30 individuals / m 3 for 2 - 3 days . no feed is supplied . at this point the water temperature is gradually raised to 19 °c at a rate of 1 °c per day . after 7 to 10 days the broodstock can be induced to spawn . during this phase it is necessary to maintain the quality of the water in the culture tanks . water exchange should be carried out rapidly , when required .
when the seawater temperature has been raised to 19 °c , the sea cucumber activity should be carefully monitored particularly during the night hours . the bottom of the tanks should be examined for the presence of oocytes as this is an indication that the sea cucumbers are likely to start mass release of gametes . there are two ways to induce spawning : the first method consists of drying the sea cucumber in the shade followed by a jet of violent water ; the second method uses a temperature shock by raising and lowering the water temperature by several degrees .
the clean seawater in the tanks should be stirred gently every 30 minutes ensuring that whirlpools do not form . edta is added at a concentration of 3 - 4 ppm while the larval density is kept at about 5 larvae / ml . the hatching success may exceed 90 % .
selection of the larvae begins before the auricularias tube - like foot is formed , or shortly after . an hour prior to the selection process , stirring is stopped in order to allow the auriculariae to gather at the surface of the tanks . malformed larvae are unable to swim and will sink to the bottom of the tanks . the larvae gathered at the surface are collected from the uppermost 0 . 5 m of the water column with the use of a fine mesh . these are then transferred to a new tank at a density of 300 larvae / litre .
after the appearance of the mouth in the auricularia larvae , feeding should commence immediately . early in the growth of the auricularia , the feeding regime should be in the range of 5 000 to 10 000 microalgae cells / ml . at the intermediate stage , feeding needs to be increased to about 20 000 cells / ml . monitoring the presence of algae in the stomach of the larvae helps the adjustment of the feeding regime . dunaliella is the primary algal species used and is generally mixed with diatoms and chaetoceros sp . the three micro - organisms are added in a proportion of 4 : 1 : 1 . the food mixture should be supplied in small quantities in order to maintain optimal water quality .
rearing during the auricularia stage should be carried out in still water . water should be added to the rearing tank at a rate of 20 cm per day until the tank is filled . this usually takes approximately 3 days . once the tank is filled , one third to a half of the water should be exchanged daily using a siphon . as the larvae grow the water exchange rate should gradually increased . water exchange should be carried out gently in order to avoid injuries or loss of larvae .
the culture of auricularia larvae requires the proper control of all major chemical and physical factors . generally speaking , the ph and salinity values should remain within the range tolerated by the larvae . stirring the water or adding new seawater will control dissolved oxygen levels . it is important to maintain the temperature at around 23 °c . if the larvae are reared in natural seawater , the temperature will rise gradually with the seasonal fluctuations . appropriate measures must be taken to maintain it within the acceptable range .
during the larval culture , the primary harmful organisms are copepods ; however their presence can be contained through a proper water exchange protocol and the use of edta ( 3 to 4 ppm ) , if necessary .
the primary symptoms of disease are a slow development rate of the larvae and the rotten stomach phenomenon observed in late auriculariae . this can be caused by food deficiency or sub - optimal larval densities . the use of quality feeds and maintaining low larvae densities can minimise the outbreak of diseases .
after the larvae have developed for 7 to 10 days , the five lipid spheres on each side of the larvae appear and the hydrocoel begins to develop . the larvae are now transforming into doliolaria . at this stage , the settlement substrates ( see figure 4 ) should be placed in the rearing tanks . the density of the larvae settled on substrate should be maintained between 1 to 2 individuals / cm 2 .
the rearing techniques at this point of the development of the sea cucumber juveniles are very important and should be carefully applied in order to ensure a high rate of survival .
the rearing tanks are fitted with a water flow through system . the presence of food particles and the relatively high water temperature are responsible for the proliferation of undesirable and harmful organisms , such as copepods and bacteria . the water in the tanks should be clean with a daily exchange rate of up to 200 % .
juvenile sea cucumbers grow at different rates and it is therefore important to sort them according to their size . this is done using sieves fitted with different mesh sizes . while sorting , care should be taken not to damage or kill the juvenile sea cucumbers .
raft culture . wooden rafts are usually located in sea areas not exposed to strong winds and tidal action . the sea cucumber cages are usually hung under the rafts or placed directly on the sea floor . during the rearing period , sea cucumbers are fed with sargassum sp . and other macroalgae . this farming method is not very popular due to the high costs involved .
intensive farming : intensive sea cucumber aquaculture has only recently developed . large quantities of rocks or other suitable substrates ( e . g . roof tiles ) are placed in the culture ponds to increase the surface area for the juvenile sea cucumbers and to provide shelter from predators . a refrigeration system or underground water supply is used to lower the water temperature in the ponds in the summer months when high temperatures can reduce growth and feeding rates . these pond facilities are expensive and therefore intensive farming is only carried out by large and financially strong companies .
the most suitable sea locations are rocky sites with an abundance of macrophytes and with muddy and sandy bottoms . areas protected from strong winds and tidal actions are usually favoured .
juveniles over 1 cm in length are used when stocking directly in the sea . the larger the initial size of the juveniles , the higher the survival rate . when stocking , the juveniles are placed in bags with a mesh size of 0 . 25 - 0 . 5 cm . a diver then places the bags on the sea bottom in the vicinity of existing rocks or artificially prepared rock piles . subsequently the mesh bags are opened and the juveniles are simply left to crawl away . larger juveniles ( > 5 cm ) can be released into the sea directly .
generally , two years after stocking , the sea cucumbers have reached a marketable size and can be collected . harvesting is often done in the spring ( mid - april to early june ) and autumn ( october to december ) ( figure 5 ) .
figure 5 . sea cucumber harvested off the coast of dalian , china ( photo : a . lovatelli ) .
sea ranching takes full advantage of the natural environment and this method is considered to be ecologically acceptable and therefore worth developing . however , due to a number of seasonal limitations and resource use conflict ( presence of industrial activities ) , this growout method can only be carried out in locations which have the right conditions .
liao , y . l . 1997 . fauna sinica , phylum echinodermata , class holothuroidea . science press , beijing . 334pp .
sui , x . l . & liao , y . l . 1988 . sea cucumber culture and its enhancement . agriculture publishing house , beijing . 288pp .
zhang , f . y . 1958 . the preliminary report of aquaculture and sea ranching of sea cucumber ( apostichopusjaponicus ) . journal of zoology , 2 ( 2 ) : 65 - 73 .
zhang , q . l . & liu , y . h . 1998 . the techniques of sea cucumber culture and its enhancement . qingdao ocean university publishing house , qingdao . 157pp .
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copyright : © 2012 du et al . this is an open - access article distributed under the terms of the creative commons attribution license , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited .
funding : financial support for this work was provided by the national key technology r & d program of china ( 2011bad13b05 and 2011bad13b06 ) , and the national high technology research and development program of china ( 2012aa10a412 ) . the funders had no role in study design , data collection and analysis , decision to publish , or preparation of the manuscript .
( a ) size distribution of raw reads . ( b ) size distribution of contigs . ( c ) log - log plot showing the dependence of contig lengths on the number of reads assembled into each . ( d ) size distribution of isotigs .
regarding gene annotation , all isogroups were searched against the swiss - prot database with an e - value threshold of 1e - 6 . of 21 , 071 isogroups , 8 , 229 ( 39 % ) had at least one hit , which corresponded to 6 , 963 unigene names . the sequences and annotation information of all isogroups are provided in dataset s1 and table s1 . more than half of the isogroups did not match to known genes most likely due to the fact that insufficient sequences are available in public databases from phylogenetically closely related species . the annotation rate in our study is also comparable to those ( 20∼40 % ) reported in the previous de novo transcriptome sequencing studies for non - model organisms [ 26 ] , [ 27 ] , [ 33 ] , [ 34 ] , [ 35 ] .
aestivation is possibly a protection strategy for sea cucumbers to survive from high temperatures [ 10 ] , [ 11 ] . studies on sea cucumber aestivation from different perspectives such as morphology [ 10 ] , [ 11 ] , [ 37 ] , physiology [ 10 ] , [ 11 ] , [ 37 ] , [ 38 ] , and immunology [ 39 ] have been performed . nonetheless , the molecular mechanism of this process is still far from fully understood . identification and characterization of candidate genes involved in aestivation would represent the first step to understand the genetic basis of aestivation in sea cucumbers .
twelve candidate dges were selected for q - pcr validation . q - pcr results verified the differential expression of these genes between the active and aestivating sea cucumbers ( figure 3 ) . however , it should be noted that many genes in the two libraries were lowly expressed and therefore were not included in the comparison . more dges would be determined from these lowly expressed genes by performing deep transcriptome sequencing in future studies .