| rapid and inexpensive analysis of genetic variability in arapaima gigas by pcr multiplex panel of eight microsatellites. | the aim of the present study was the development of a multiplex genotyping panel of eight microsatellite markers of arapaima gigas, previously described. specific primer pairs were developed, each one of them marked with either fam-6, hex or ned. the amplification conditions using the new primers were standardized for a single reaction. the results obtained demonstrate high heterozygosity (average of 0.69) in a lower amazon population. the multiplex system described can thus be considered a fast ... | 2008 | 18273816 |
| conservation strategies for arapaima gigas (schinz, 1822) and the amazonian várzea ecosystem. | in the present study we report a spatial autocorrelation analysis of molecular data obtained for arapaima gigas, and the implication of this study for conservation and management. arapaima is an important, but critically over-exploited giant food fish of the amazonian várzea. analysis of 14 variable microsatellite loci and 2,347 bp of mtdna from 126 individuals sampled in seven localities within the amazon basin suggests that arapaima forms a continuous population with extensive genetic exchange ... | 2007 | 18278359 |
| the monotony of transferrin and esterase electrophoretic patterns in pirarucu, arapaima gigas (schinz, 1822) from santa cruz lake, tefé river, amazonas, brazil. | starch gel electrophoresis was used for examining the transferrin gene locus (tf) and two esterase gene loci (est-1 and est-d1) of a pirarucu (arapaima gigas) population sample collected from santa cruz lake, tefé river, amazonas, brazil. the tf locus was tentatively classified as being polymorphic, showing two double-banded patterns (tf(12) and tf(22)) of the three theoretically expected ones (tf(11), tf(12) and tf(22)), presumably controlled by two co-dominant alleles, tf(1) and tf(2). the mon ... | 2008 | 18551407 |
| capillostrongyloides arapaimae sp. n. (nematoda: capillariidae), a new intestinal parasite of the arapaima arapaima gigas from the brazilian amazon. | a new nematode species, capillostrongyloides arapaimae sp. n., is described from the intestine and pyloric caeca of the arapaima, arapaima gigas (schinz), from the mexiana island, amazon river delta, brazil. it is characterized mainly by the length of the spicule (779-1,800 microm), the large size of the body (males and gravid females 9.39-21.25 and 13.54-27.70 mm long, respectively) and by the markedly broad caudal lateral lobes in the male. it is the third species of genus capillostrongyloides ... | 2008 | 18660995 |
| immunocytochemical identification of adenohypophyseal cells in the pirarucu (arapaima gigas), an amazonian basal teleost. | the adenohypophysis (ah) of juvenile pirarucu (arapaima gigas), a representative species of the osteoglossomorpha (bonytongue fishes, one of the oldest living groups of the teleosts), was studied using histochemical and immunocytochemical methods. the ah is comprised of the pars distalis (pd), without a clear distinction between rostral pars distalis (rpd) and proximal pars distalis (ppd), and the pars intermedia (pi). the neurohypophysis (nh) is positioned on top of the pd and penetrates and br ... | 2009 | 18758983 |
| light and scanning electron microscopy of henneguya arapaima n. sp. (myxozoa: myxobolidae) and histology of infected sites in pirarucu (arapaima gigas: pisces: arapaimidae) from the araguaia river, brazil. | in this report, we describe henneguya arapaima n. sp., a parasite of the gill arch and gall bladder of arapaima gigas (pirarucu) collected in the araguaia river, in the municipality of nova crixás, goiás state, central brazil. the plasmodia were white, round or ellipsoidal and measured 200-600 microm. parasite development was asynchronous and the mature spores were fusiform and had smooth wall. the spores measurements were (range, with means+/-s.d. in parentheses): total length-48.4-53.1 microm ... | 2008 | 18771855 |
| patterns of commercial fish landings in the loreto region (peruvian amazon) between 1984 and 2006. | patterns of commercial fish catches over the period from 1984 to 2006 were studied in the loreto region and in iquitos, which is the most important town of the region and the principal fish marketplace of the peruvian amazon. despite important inter-annual variations, the overall fish landings have significantly increased in the region during this period. the same three species dominated the catches during the whole period (prochilodus nigricans, potamorhina altamazonica and psectrogaster amazon ... | 2009 | 19189235 |
| gender determination in the paiche or pirarucu (arapaima gigas) using plasma vitellogenin, 17beta-estradiol, and 11-ketotestosterone levels. | arapaima gigas is an air-breathing giant fish of amazonian rivers. given its great economic and cultural importance, the aquaculture development of this species represents an evident solution to face the decline of wild populations. in captivity, reproduction occurs generally in large earthen ponds where stocks of a few tens of brooders are maintained together at the beginning of the rainy season (december-march in the peruvian amazon). fry production relies on the spontaneous formation of male ... | 2009 | 19189239 |
| tissue-dwelling philometrid nematodes of the fish arapaima gigas in brazil. | the nematode rumai rumai travassos, 1960 (philometridae) is redescribed from the tissues of the mouth, tongue, operculum and head of the arapaima, arapaima gigas (schinz) (osteichthyes), from mexiana island, amazon river delta, brazil. additional data on the related nilonema senticosum (baylis, 1922) from the same host and locality are also presented. rumai rumai is characterized by the presence of a sclerotized formation on the female cephalic end, dorsal and ventral cephalic projections, the s ... | 2009 | 19224666 |
| [helminth parasites of pirarucu, arapaima gigas (schinz, 1822) (osteoglossiformes: arapaimidae) from araguaia river, state of mato grosso, brazil]. | sixty-five specimens of pirarucu collected in august 2004 from araguaia river, state of mato grosso, brazil, were examined to study their helminth parasites. five species were recorded parasitic arapaima gigas: dawestrema cycloancistrium (monogenea) in gills, nilonema senticosum and goezia spinulosa (nematoda) in the swimbladder and stomach, respectively; caballerotrema brasiliense (digenea) and polyacanthorhynchus rhopalorhynchus (acanthocephala) in the intestine. highest prevalence values were ... | 2008 | 19245767 |
| camallanus tridentatus (drasche) (nematoda: camallanidae): new taxonomically important morphological data. | camallanus tridentatus is redescribed on the basis of the examination of specimens obtained from the stomach, caeca and intestine of the naturally infected arapaima arapaima gigas (schinz) from the mexiana island, amazon river delta, brazil. data on the surface morphology of adults inferred from confocal laser scanning and scanning electron microscopical observations are also provided. the study revealed some taxonomically important, previously unreported morphological features in this species, ... | 2009 | 19274382 |
| goezia spinulosa (nematoda: raphidascarididae), a pathogenic parasite of the arapaima arapaima gigas (osteichthyes). | the nematode goezia spinulosa (diesing, 1839) (raphidascarididae) is redescribed based on specimens found in the stomach and intestine of the naturally infected arapaima arapaima gigas (schinz) from the mexiana island, amazon river delta, brazil. light and electron microscopy examinations revealed some previously unreported or inaccurately described morphological features in the species, such as the position of the excretory pore, phasmids in the male or the number (4) of postanal papillae. the ... | 2009 | 19391331 |
| the evolution of root effect hemoglobins in the absence of intracellular ph protection of the red blood cell: insights from primitive fishes. | the root effect, a reduction in blood oxygen (o(2)) carrying capacity at low ph, is used by many fish species to maximize o(2) delivery to the eye and swimbladder. it is believed to have evolved in the basal actinopterygian lineage of fishes, species that lack the intracellular ph (ph(i)) protection mechanism of more derived species' red blood cells (i.e., adrenergically activated na(+)/h(+) exchangers; betanhe). these basal actinopterygians may consequently experience a reduction in blood o(2) ... | 2010 | 20213180 |
| permanent genetic resources added to molecular ecology resources database 1 december 2010-31 january 2011. | this article documents the addition of 238 microsatellite marker loci to the molecular ecology resources database. loci were developed for the following species: alytes dickhilleni, arapaima gigas, austropotamobius italicus, blumeria graminis f. sp. tritici, cobitis lutheri, dendroctonus ponderosae, glossina morsitans morsitans, haplophilus subterraneus, kirengeshoma palmata, lysimachia japonica, macrolophus pygmaeus, microtus cabrerae, mytilus galloprovincialis, pallisentis (neosentis) celatus, ... | 2011 | 21457476 |
| lethal dose and clinical signs of aeromonas hydrophila in arapaima gigas (arapaimidae), the giant fish from amazon. | aeromonas hydrophila is causing substantial economic losses in world aquaculture. this study determined the tolerance limit (ld50-96h) of a. hydrophila in arapaima gigas, and also investigated the clinical signs after intradermal inoculation. arapaima gigas fingerlings were inoculated intraperitoneally with 0 (control), 1.0×10(5), 1.0×10(6), 1.0×10(7), 1.0×10(9) and 1.0×10(10)cfu/ml of a. hydrophila for the determination of ld50-96h, which was 1.8×10(8)cfu/ml. in another trial with intradermal i ... | 2016 | 27139024 |
| rapid-communication genetic diversity and differentiation in natural populations of arapaima gigas from lower amazon revealed by microsatellites. | genetic variability is one of the important criteria for species conservation decisions. this study aimed to analyze the genetic diversity and the population differentiation of two natural populations of arapaima gigas, a species with a long history of being commercially exploited. we collected 87 samples of a. gigas from grande curuai lake and paru lake, located in the lower amazon region of amazônia, brazil, and genotyped these samples using a multiplex panel of microsatellite markers. our res ... | 2017 | 28198511 |
| a comparative study of piscine defense: the scales of arapaima gigas, latimeria chalumnae and atractosteus spatula. | we compare the characteristics of the armored scales of three large fish, namely the arapaima gigas (arapaima), latimeria chalumnae (coelacanth), and atractosteus spatula (alligator gar), with specific focus on their unique structure-mechanical property relationships and their specialized ability to provide protection from predatory pressures, with the ultimate goal of providing bio-inspiration for manmade materials. the arapaima has flexible and overlapping cycloid scales which consist of a tou ... | 2016 | 27816416 |
| molecular and functional characterization of a fads2 orthologue in the amazonian teleost, arapaima gigas. | the brazilian teleost arapaima gigas is an iconic species of the amazon. in recent years a significant effort has been put into the farming of arapaima to mitigate overfishing threats. however, little is known regarding the nutritional requirements of a. gigas in particular those for essential fatty acids including the long-chain polyunsaturated fatty acids (lc-pufa) eicosapentaenoic acid (epa) and docosahexaenoic acid (dha). the ability to biosynthesize lc-pufa is dependent upon the gene repert ... | 2017 | 27693628 |
| the natural armors of fish: a comparison of the lamination pattern and structure of scales. | fish scales exhibit a unique balance of flexibility, strength and toughness, which is essential to provide protection without encumbering locomotion. although the mechanical behavior and structure of this natural armor are of recent interest, a comparison of these qualities from scales of different fish species has not been reported. in this investigation the armor of fish with different locomotion, size and protection needs were analyzed. scales from the arapaima gigas, the tarpon (megalops atl ... | 2016 | 27745845 |
| community-based management induces rapid recovery of a high-value tropical freshwater fishery. | tropical wetlands are highly threatened socio-ecological systems, where local communities rely heavily on aquatic animal protein, such as fish, to meet food security. here, we quantify how a 'win-win' community-based resource management program induced stock recovery of the world's largest scaled freshwater fish (arapaima gigas), providing both food and income. we analyzed stock assessment data over eight years and examined the effects of protected areas, community-based management, and landscap ... | 2016 | 27731319 |
| unravelling the life history of amazonian fishes through otolith microchemistry. | amazonian fishes employ diverse migratory strategies, but the details of these behaviours remain poorly studied despite numerous environmental threats and heavy commercial exploitation of many species. otolith microchemistry offers a practical, cost-effective means of studying fish life history in such a system. this study employed a multi-method, multi-elemental approach to elucidate the migrations of five amazonian fishes: two 'sedentary' species (arapaima sp. and plagioscion squamosissimus), ... | 2016 | 27429777 |
| recovery of arapaima sp. populations by community-based management in floodplains of the purus river, amazon. | in the present study a unique dataset on population abundance in various community-based management (cbm) and non-cbm areas is analysed to address the question of whether cbm can recover overexploited populations of arapaima sp. in river-floodplain ecosystems. all non-cbm areas possessed depleted arapaima sp. populations with a mean density of 0·01 individuals ha(-1) . arapaima sp. population densities in all cbm areas changed over time from depleted to overexploited or well managed status, with ... | 2016 | 27094974 |
| the fortune of the commons: participatory evaluation of small-scale fisheries in the brazilian amazon. | this paper applies a participatory approach in evaluating small-scale fisheries, focusing on the arapaima gigas fishery in the brazilian amazon. the evaluation uses the social-ecological system (ses) framework, adopted to explain the conditions needed for sustainability and user cooperation in natural resources management, as a more suitable alternative to the 'blueprint' or 'panaceas' approaches, based only on property rights or governmental intervention. however, managers and users often do no ... | 2016 | 26796697 |
| novel, major 2α- and 2β-hydroxy bile alcohols and bile acids in the bile of arapaima gigas, a large south american river fish. | bile alcohols and bile acids from gallbladder bile of the arapaima gigas, a large south american freshwater fish, were isolated by reversed-phase high-performance liquid chromatography. the structures of the major isolated compounds were determined by electrospray-tandem mass spectrometry and nuclear magnetic resonance using (1)h- and (13)c-nmr spectra. the novel bile salts identified were six variants of 2-hydroxy bile acids and bile alcohols in the 5α- and 5β-series, with 29% of all compounds ... | 2016 | 26768415 |
| first record of larvae of hysterothylacium (nematoda: anisakidae) with zoonotic potential in the pirarucu arapaima gigas (osteichthyes: arapaimidae) from south america. | third-stage larvae (l3) of hysterothylacium sp. were collected by the first time in juveniles of pirarucu arapaima gigas farmed in the rio preto da eva, amazonas state. ninety-eight (98) out of 100 examined fish showed to be parasitized. five hundred and ninety larvae of hysterothylacium sp. were collected from the intestines, stomach and pyloric caeca. the mean intensity of parasite indexes was 6.02 (±5.75) ranging from 1 to 40 larvae per host and the mean abundance was 5.9 (±5.76). the a. giga ... | 2015 | 26675898 |
| first record of larvae of hysterothylacium (nematoda: anisakidae) with zoonotic potential in the pirarucu arapaima gigas (osteichthyes: arapaimidae) from south america. | third-stage larvae (l3) of hysterothylacium sp. were collected by the first time in juveniles of pirarucu arapaima gigas farmed in the rio preto da eva, amazonas state. ninety-eight (98) out of 100 examined fish showed to be parasitized. five hundred and ninety larvae of hysterothylacium sp. were collected from the intestines, stomach and pyloric caeca. the mean intensity of parasite indexes was 6.02 (±5.75) ranging from 1 to 40 larvae per host and the mean abundance was 5.9 (±5.76). the a. giga ... | 2015 | 26628239 |
| impact and fracture analysis of fish scales from arapaima gigas. | fish scales from the amazonian fish arapaima gigas have been characterised to study their impact and fracture behaviour at three different environmental conditions. scales were cut in two different directions to analyse the influence of the orientation of collagen layers. the energy absorbed during impact tests was measured for each sample and sem images were taken after each test in order to analyse the failure mechanisms. the results showed that scales tested at cryogenic temperatures display ... | 2015 | 25842120 |
| the floating forest: traditional knowledge and use of matupá vegetation islands by riverine peoples of the central amazon. | matupás are floating vegetation islands found in floodplain lakes of the central brazilian amazon. they form initially from the agglomeration of aquatic vegetation, and through time can accumulate a substrate of organic matter sufficient to grow forest patches of several hectares in area and up to 12 m in height. there is little published information on matupás despite their singular characteristics and importance to local fauna and people. in this study we document the traditional ecological kn ... | 2015 | 25837281 |
| characterization of dermal plates from armored catfish pterygoplichthys pardalis reveals sandwich-like nanocomposite structure. | dermal plates from armored catfish are bony structures that cover their body. in this paper we characterized structural, chemical, and nanomechanical properties of the dermal plates from the amazonian fish pterygoplichthys pardalis. analysis of the morphology of the plates using scanning electron microscopy (sem) revealed that the dermal plates have a sandwich-like structure composed of an inner porous matrix surrounded by two external dense layers. this is different from the plywood-like lamina ... | 2015 | 25732181 |
| finite element modeling of multilayered structures of fish scales. | the interlinked fish scales of atractosteus spatula (alligator gar) and polypterus senegalus (gray and albino bichir) are effective multilayered armor systems for protecting fish from threats such as aggressive conspecific interactions or predation. both types of fish scales have multi-layered structures with a harder and stiffer outer layer, and softer and more compliant inner layers. however, there are differences in relative layer thickness, property mismatch between layers, the property grad ... | 2014 | 25300062 |
| characterization of catalytic efficiency parameters of brain cholinesterases in tropical fish. | brain cholinesterases from four fish (arapaima gigas, colossoma macropomum, rachycentron canadum and oreochromis niloticus) were characterized using specific substrates and selective inhibitors. parameters of catalytic efficiency such as activation energy (ae), k(cat) and k(cat)/k(m) as well as rate enhancements produced by these enzymes were estimated by a method using crude extracts described here. despite the bche-like activity, specific substrate kinetic analysis pointed to the existence of ... | 2014 | 24980148 |
| protective role of arapaima gigas fish scales: structure and mechanical behavior. | the scales of the arapaima (arapaima gigas), one of the largest freshwater fish in the world, can serve as inspiration for the design of flexible dermal armor. each scale is composed of two layers: a laminate composite of parallel collagen fibrils and a hard, highly mineralized surface layer. we review the structure of the arapaima scales and examine the functions of the different layers, focusing on the mechanical behavior, including tension and penetration of the scales, with and without the h ... | 2014 | 24816264 |
| seasonality influence on biochemical and hematological indicators of stress and growth of pirarucu (arapaima gigas), an amazonian air-breathing fish. | environmental factors such as seasonal cycles are the main chronic stress cause in fish increasing incidence of disease and mortality and affecting productive performance. arapaima gigas (pirarucu) is an amazonian air-breathing and largest freshwater fish with scales in the world. the captivity development of pirarucu is expanding since it can fatten up over 1 kg per month reaching 10 kg body mass in the first year of fattening. this work was conducted in three periods (april to july 2010, augus ... | 2014 | 24578643 |
| high infestation by dawestrema cycloancistrioides in arapaima gigas cultured in the amazon region, peru. | the aim of this study was to evaluate the presence of dawestrema cycloancistrioides in semi-intensive fish farming of fingerlings of arapaima gigas. between september and november 2013, 60 individuals of a. gigas born in captivity, were collected in three concrete ponds, from a semi-intensive fish farm in the peruvian amazon. for the study of sclerotized structures, parasites were fixed in a solution of ammonium picrate glycerine and mounted in canada balsam. to visualize internal structures, pa ... | 2014 | 26464924 |
| bulked segregant analysis of the pirarucu (arapaima gigas) genome for identification of sex-specific molecular markers. | arapaima gigas (osteoglossidae) is one of the largest fish species in the amazon basin, attaining lengths of over 2.5 m and weights of over 100 kg. its flesh is prized, and it has great potential for production in aquaculture systems. however, live pirarucu cannot be reliably sexed visually, even after sexual development, since this species does not have clear external sexual dimorphism. simple and inexpensive methods for sexing immature pirarucu based on dna markers would facilitate production ... | 2013 | 24338425 |
| profile of micronucleus frequencies and nuclear abnormalities in different species of electric fishes (gymnotiformes) from the eastern amazon. | the frequency of spontaneous micronucleus (mn) formation in fish species needs to be determined to evaluate their usefulness for genotoxic biomonitoring. the definition of a good bioindicator takes into account the current knowledge of its metabolic traits as well as other factors including its feeding behavior and relationship to the environment. in this study, we compared the basal frequencies of micronucleated erythrocytes and nuclear abnormalities (na) among different species of the fish ord ... | 2013 | 24130451 |
| mechanical adaptability of the bouligand-type structure in natural dermal armour. | arapaima gigas, a fresh water fish found in the amazon basin, resist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour. arapaima scales consist of a hard, mineralized outer shell surrounding a more ductile core. this core region is composed of aligned mineralized collagen fibrils arranged in distinct lamellae. here we show how the bouligand-type (twisted plywood) arrangement of collagen fibril lamellae has a key role in developing their ... | 2013 | 24129554 |
| implications for osmorespiratory compromise by anatomical remodeling in the gills of arapaima gigas. | the gill structure of the amazonian fish arapaima gigas, an obligatory air breather, was investigated during its transition from water breathing to the obligatory air breathing modes of respiration. the gill structure of a. gigas larvae is similar to that of most teleost fish; however, the morphology of the gills changes as the fish grow. the main morphological changes in the gill structure of a growing fish include the following: (1) intense cell proliferation in the filaments and lamellae, res ... | 2013 | 23956000 |
| parasitic infections in juveniles of arapaima gigas (schinz, 1822) cultivated in the peruvian amazon. | the paiche, arapaima gigas represents a socio-economically important species in the peruvian amazon, and actually an intensive production for human consumption has emerged during the last years. therefore, more studies are required in fish farming development, especially concerning populations of parasites that affect fish production yields. eighty specimens of paiche collected between september and october of 2011 from semi-intensive fish farm in loreto state, peru, were examined for their helm ... | 2013 | 23829058 |
| are nors always located on homeologous chromosomes? a fish investigation with rdna and whole chromosome probes in gymnotus fishes (gymnotiformes). | gymnotus (gymnotiformes, gymnotidae) is the most diverse known neotropical electric knife fish genus. cytogenetic studies in gymnotus demonstrate a huge karyotypic diversity for this genus, with diploid numbers ranging from 34 to 54. the nor are also variable in this genus, with both single and multiple nors described. a common interpretation is that the single nor pair is a primitive trait while multiple nors are derivative. however this hypothesis has never been fully tested. in this report we ... | 2013 | 23405178 |
| dispersal capacity and genetic structure of arapaima gigas on different geographic scales using microsatellite markers. | despite the ecological and economic importance of the arapaima gigas (cuvier 1817), few data about its dispersal capacity are available. the present study was based on the analysis of microsatellite markers in order to estimate the dispersal capacity of the species on fine, meso, and large geographic scales. for this, 561 specimens obtained from stocks separated by distances of up to 25 km (fine scale), 100 km (meso scale), and 1300-2300 km (large scale) were analyzed. the fine scale analysis in ... | 2013 | 23372730 |
| natural flexible dermal armor. | fish, reptiles, and mammals can possess flexible dermal armor for protection. here we seek to find the means by which nature derives its protection by examining the scales from several fish (atractosteus spatula, arapaima gigas, polypterus senegalus, morone saxatilis, cyprinius carpio), and osteoderms from armadillos, alligators, and leatherback turtles. dermal armor has clearly been developed by convergent evolution in these different species. in general, it has a hierarchical structure with co ... | 2013 | 23161399 |
| comparative effect of pesticides on brain acetylcholinesterase in tropical fish. | monitoring of pesticides based on acetylcholinesterase (ache; ec 3.1.1.7) inhibition in vitro avoids interference of detoxification defenses and bioactivation of some of those compounds in non-target tissues. moreover, environmental temperature, age and stress are able to affect specific enzyme activities when performing in vivo studies. few comparative studies have investigated the inter-specific differences in ache activity in fish. screening studies allow choosing the suitable species as sour ... | 2012 | 23137979 |
| isolation of the pituitary gonadotrophic α-subunit hormone of the giant amazonian fish: pirarucu (arapaima gigas). | the cdnas of the α-subunit of the pituitary gonadotrophic hormones (gthα) of fish of the order osteoglossiformes or the superorder osteoglossomorpha have never been sequenced. for a better understanding the phylogenetic diversity and evolution of pghα in fish and for future biotechnological synthesis of the gonadotrophic hormones (ag-fsh and ag-lh), of arapaima gigas, one of the largest freshwater fishes of the world, its gthα cdna was synthesized by reverse transcriptase and the polymerase chai ... | 2013 | 23073850 |
| morphometric partitioning of the respiratory surface area and diffusion capacity of the gills and swim bladder in juvenile amazonian air-breathing fish, arapaima gigas. | the gills and the respiratory swim bladders of juvenile specimens (mean body mass 100g) of the basal teleost arapaima gigas (cuvier 1829) were evaluated using stereological methods in vertical sections. the surface areas, harmonic mean barrier thicknesses and morphometric diffusing capacities for oxygen and carbon dioxide were estimated. the average respiratory surface area of the swim bladder (2173 cm² kg⁻¹) exceeded that of the gills (780 cm² kg⁻¹) by a factor of 2.79. due to the extremely thi ... | 2012 | 22512942 |
| tissue alterations in the pirarucu, arapaima gigas, infected by goezia spinulosa (nematoda). | five specimens of arapaima gigas caught in the araguaia river (state of mato grosso, brazil) were investigated for helminths in 2004. numerous adult specimens of the rhapidascarid nematode goezia spinulosa were found in stomach ulcers in all the specimens of a. gigas and were surrounded by thickening of the mucosa. the gastric glands of all the fish were necrotic and there was a severe and diffuse inflammatory reaction composed of eosinophils (which were predominant), lymphocytes and rare macrop ... | 2011 | 21961749 |
| mechanical properties and the laminate structure of arapaima gigas scales. | the arapaima gigas scales play an important role in protecting this large amazon basin fish against predators such as the piranha. they have a laminate composite structure composed of an external mineralized layer and internal lamellae with thickness of 50-60 μm each and composed of collagen fibers with ~1 μm diameter. the alignment of collagen fibers is consistent in each individual layer but varies from layer to layer, forming a non-orthogonal plywood structure, known as bouligand stacking. x- ... | 2011 | 21783123 |
| uva/uvb-induced genotoxicity and lesion repair in colossoma macropomum and arapaima gigas amazonian fish. | ultraviolet radiation is known to cause adverse effects to aquatic species and aquatic environments. the fish colossoma macropomum (tambaqui) and arapaima gigas (pirarucu) live in the amazon basin, near the equator, and thus receive high intensity of ultraviolet radiation. deforestation further aggravates the situation by reducing shade at ground level. the aim of this study was to evaluate the genotoxic effects of uva and uvb radiation on erythrocytes of tambaqui and pirarucu fish using micronu ... | 2010 | 20338776 |
| impact of ontogenetic changes in branchial morphology on gill function in arapaima gigas. | soon after hatching, the osteoglossid fish arapaima gigas undergoes a rapid transition from a water breather to an obligate air breather. this is followed by a gradual disappearance of gill lamellae, which leaves smooth filaments with a reduced branchial diffusion capacity due to loss of surface area, and a fourfold increase in diffusion distance. this study evaluated the effects these changes have on gill function by examining two size classes of fish that differ in gill morphology. in comparis ... | 2013 | 20100089 |
| microsatellite markers for the silver arowana (osteoglossum bicirrhosum, osteoglossidae, osteoglossiformes). | osteoglossum bicirrhosum (silver arowana) is an important fish for the economy of the amazon region, both as an ornamental fish and as a food fish. to provide tools for addressing ecological and genetic questions, we developed 19 polymorphic microsatellite markers that had between 2 and 7 alleles per locus in the 24 tested individuals. the transferability of many of the loci was confirmed for osteoglossum ferreirai (black arowana) and arapaima gigas, and for three african osteoglossiform species ... | 2009 | 21564825 |
| net ion fluxes in the facultative air-breather hoplosternum littorale (tamoata) and the obligate air-breather arapaima gigas (pirarucu) exposed to different amazonian waters. | fishes that live in the amazon environment may be exposed to several kinds of water: black water (bw), acidic black water (ph 3.5) (abw) and white water (ww), among others. the aim of the present study was to analyze net ion fluxes in the facultative air-breather hoplosternum littorale (tamoata) and the obligate air-breather arapaima gigas (pirarucu) exposed to different types of water. fishes were acclimated in well water and later placed in individual chambers containing one type of water for ... | 2008 | 18958598 |
| lessons from integrating fishers of arapaima in small-scale fisheries management at the mamirauá reserve, amazon. | fishers and small-scale fisheries worldwide have been marginalized historically. now it is clear that integrating fishers in management processes is key to resource conservation, but it is less clear how to do it. here, based on a literature review and new information, we present and analyze a case in which the participation of fishers in the management process was crucial in recovering an overexploited small-scale fishery for the pirarucu (arapaima spp.) in the amazon basin, brazil. in 8 years ... | 2009 | 18946698 |
| nilonema gymnarchi khalil, 1960 and n. senticosum (baylis, 1922) (nematoda: dracunculoidea): gondwana relicts? | data-base searches of records of the helminth parasites of south american and african freshwater fishes revealed only two pairs of species from genera endemic to the two regions. one pair, species of the primitive amphilinid cestode genus nesolecithus dönges & harder, 1966, has already been designated as likely gondwana relicts. the second pair are the philometrid nematodes nilonema gymnarchi khalil, 1960 from gymnarchus niloticus cuvier (gymnarchidae) in africa and n. senticosum (baylis, 1922) ... | 2007 | 17464484 |
| stereological estimation of surface area and barrier thickness of fish gills in vertical sections. | previous morphometric methods for estimation of the volume of components, surface area and thickness of the diffusion barrier in fish gills have taken advantage of the highly ordered structure of these organs for sampling and surface area estimations, whereas the thickness of the diffusion barrier has been measured orthogonally on perpendicularly sectioned material at subjectively selected sites. although intuitively logical, these procedures do not have a demonstrated mathematical basis, do not ... | 2007 | 17286690 |
| the influence of dietary vitamin c and e supplementation on the physiological response of pirarucu, arapaima gigas, in net culture. | this study evaluated the efficacy of dietary vitamin c (ascorbic acid or aa), vitamin e (alpha-tocopherol or alpha-t), and c+e supplementation on the blood parameters of arapaima gigas grown in net cages for 45 days. four treatments were tested: control (commercial feed); c800; e500 and c+e (800+500) with supplementation of 800 mg aa kg(-1), 500 mg alpha-t kg(-1) and 800+500 mg aa+alpha-t kg(-1), respectively. hematocrit (ht), red blood cells (rbc), and hemoglobin concentration (hb) (oxidative s ... | 2006 | 16934509 |
| hepatic calyptospora sp. (apicomplexa) infection in a wild-born, aquarium-held clutch of juvenile arapaima arapaima gigas (osteoglossidae). | from manaus, brazil, 12 juvenile arapaima arapaima gigas were imported to the united states and sent to 2 public aquaria, 1 private hobbyist, and 1 retailer. all 12 fish became ill within 4 to 6 wk of arrival, with signs of anorexia, lethargy, depigmentation, and ascites, and subsequently died despite antibiotic and anthelminthic therapy. gross necropsies of 7 fish revealed serosanguinous coelomic effusion in all 7 fish, and branchial monogeneosis in 3 of 6 fish. the monogeneans from 1 fish were ... | 2006 | 16875394 |
| influence of diets supplemented with vitamins c and e on pirarucu (arapaima gigas) blood parameters. | this study evaluated the influence of diets supplemented with 500, 800, 1200 mg kg-1 of vitamin c (ascorbic acid or aa) and vitamin e (alpha-tocopherol or alpha-t) on the physiological responses of pirarucu fed for 2 months. weight and mortality were not affected by dietary vitamin type or their concentrations. significant increase (p<0.05) on the red blood cells count was obtained on treatments with 800 and 1200 mg aa kg-1 and on the hemoglobin concentration on treatment with 500 mg alpha-t kg- ... | 2007 | 16716624 |
| the origin and evolution of the surfactant system in fish: insights into the evolution of lungs and swim bladders. | several times throughout their radiation fish have evolved either lungs or swim bladders as gas-holding structures. lungs and swim bladders have different ontogenetic origins and can be used either for buoyancy or as an accessory respiratory organ. therefore, the presence of air-filled bladders or lungs in different groups of fishes is an example of convergent evolution. we propose that air breathing could not occur without the presence of a surfactant system and suggest that this system may hav ... | 2010 | 15547792 |
| simultaneous analysis of five molecular markers provides a well-supported phylogenetic hypothesis for the living bony-tongue fishes (osteoglossomorpha: teleostei). | fishes of the superorder osteoglossomorpha (the "bonytongues") constitute a morphologically heterogeneous group of basal teleosts, including highly derived subgroups such as african electric fishes, the african butterfly fish, and old world knifefishes. lack of consensus among hypotheses of osteoglossomorph relationships advanced during the past 30 years may be due in part to the difficulty of identifying shared derived characters among the morphologically differentiated extant families of this ... | 2004 | 15324846 |
| transition in organ function during the evolution of air-breathing; insights from arapaima gigas, an obligate air-breathing teleost from the amazon. | the transition from aquatic to aerial respiration is associated with dramatic physiological changes in relation to gas exchange, ion regulation, acid-base balance and nitrogenous waste excretion. arapaima gigas is one of the most obligate extant air-breathing fishes, representing a remarkable model system to investigate (1) how the transition from aquatic to aerial respiration affects gill design and (2) the relocation of physiological processes from the gills to the kidney during the evolution ... | 2004 | 15037637 |
| molecular phylogeny of osteoglossoids: a new model for gondwanian origin and plate tectonic transportation of the asian arowana. | one of the traditional enigmas in freshwater zoogeography has been the evolutionary origin of scleropages formosus inhabiting southeast asia (the asian arowana), which is a species threatened with extinction among the highly freshwater-adapted fishes from the order osteoglossiformes. dispersalists have hypothesized that it originated from the recent (the miocene or later) transmarine dispersal of morphologically quite similar australasian arowanas across wallace's line, but this hypothesis has b ... | 2000 | 11110903 |
| encephalization and brain organization of the fishes of the family osteoglossidae. | despite their primitive place in the classification of fishes, osteoglossids have a high level of encephalization, which can be analyzed by studying their brain organization. the quantitative analysis of their main brain parts shows small relative volumes of the olfactory bulbs, normal importance of the optic tectum (linked to vision) and of the cerebellum (linked to motor abilities). the medulla oblongata shows very large gustatory lobes in heterotis, due to the special microphagous mode of fee ... | 1995 | 7751605 |
| hydrogen shuttles in gills of water versus air breathing osteoglossids. | 1. using subcellular preparations of gills from arapaima, an obligate air breather, and aruana, a related osteoglossid that is an obligate water breather, a comparison was made of the relative roles of the malate-aspartate cycle and the alpha-glycerophosphate (alpha-gp) cycle in transferring reducing equivalents from the cytosol to the mitochondria. 2. in aruana gill preparations, the alpha-gp cycle could be most clearly demonstrated by reconstructing it with purified isolated mitochondria, usin ... | 1979 | 318400 |
| hydrogen shuttles in air versus water breathing fishes. | 1. the malate-aspartate cycle was demonstrable in subcellular preparations of hearts from arapaima, lepidosiren, and synbranchus (obligate air breathers), hoplerythriunus (facultative air breather), and osteoglossum and hoplias (obligate water breathers). 2. although no respiratory evidence for significant alpha-glycerophosphate cycle participation could be shown in the air breathers, this cycle was demonstrable in hearts of water breathers. 3. in agreement with the o2 uptake studies, it was pos ... | 1979 | 318399 |
| inositol pentaphosphate in erythrocytes of a freshwater fish, piraracú arapaima gigas. | | 1977 | 850465 |
| comparative studies of bile salts. a new type of bile salt from arapaima gigas (cuvier) (family osteoglossidae). | 1. arapaima gigas bile salts were hydrolysed by alkali or cleaved with dioxan-trichloroacetic acid to give cholic acid, arapaimic acid, arapaimol-a and arapaimol-b. 2. i.r., n.m.r. and mass spectroscopy and [alpha](d) measurements indicated that arapaimic acid and arapaimol-a and -b are respectively 2alpha,3alpha,7alpha,12alpha-tetrahydroxy-5beta,25in-cholestan-26-oic acid, 5beta,25r-cholestane-2beta,3alpha,7alpha,12alpha,26-pentol and 5beta-cholestane-2beta,3alpha,7alpha,12alpha,26,27-hexol. 3. ... | 1972 | 5073728 |