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1.
PLoS One ; 15(2): e0228483, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027722

RESUMO

The aim of this study was to select a candidate deep-sea amphipod species suitable for connectivity analyses in areas around cobalt-rich ferromanganese crusts (CRCs). We applied DNA barcoding based on the mitochondrial protein-coding gene, cytochrome c oxidase subunit I (COI), to specimens collected from the Xufu Guyot (the JA06 Seamount) off southeastern Minami-Torishima Island in the North Pacific, where CRCs are distributed. We used baited traps to collect 37 specimens. Comparison of COI sequences with public reference databases (GenBank, BOLD) showed that almost all of the specimens belonged to the superfamily Lysianassoidea, which is known to be ubiquitous in deep-sea areas. In a molecular taxonomic analysis of these sequences, we detected 11 clades. One of these clades (group 9) composed of 18 sequences and was identified by DNA barcoding as a putative species belonging to Abyssorchomene, which has been reported from the New Hebrides Trench in the South Pacific. We considered this species to be a candidate for connectivity analysis and analyzed its genome by restriction site-associated DNA sequencing. The results showed that the genetic variation in this species is adequate for analyzing connectivity patterns in CRC areas in the future.


Assuntos
Anfípodes/classificação , Anfípodes/genética , Cobalto/química , Código de Barras de DNA Taxonômico/métodos , Sedimentos Geológicos/química , Ferro/química , Manganês/química , Animais , Variação Genética , Japão , Oceanos e Mares , Filogenia , Análise de Sequência de DNA/veterinária , Especificidade da Espécie , Vanuatu
2.
Biochem Genet ; 58(1): 157-170, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31410625

RESUMO

Amphipods of the superfamily Lysianassoidea that inhabit the hadal zone ( > 6000 m) have large bathymetric ranges and play a key role in deep ocean ecosystems. The endemism of these amphipod species makes them a good model for investigating potent natural selection and restricted dispersal in deep ocean trenches. Here, we describe genetic diversity and intraspecific population differentiation among three amphipod species from four Pacific trenches based on a mtDNA concatenated dataset (CO Ι and 16S rRNA genes) from 150 amphipod individuals. All amphipod populations had low genetic diversity, as indicated by haplotype and nucleotide diversity values. Population geographic relationship analysis of two Alicella gigantea populations revealed no genetic differentiation between these two localities (pairwise genetic differentiation coefficient = 0.00032, gene flow = 784.58), and the major variation (99.97%) was derived from variation within the populations. Historical demographic events were investigated using Tajima's D and Fu's F neutrality tests and analysis of mismatch distribution. Consistent results provided strong evidence to support the premise that demographic expansion occurred only for the Mariana population of Hirondellea gigas, possibly within the last 2.1-3.4 million years. These findings suggest that the formation of amphipod population structure might be the result of multiple factors including high hydrostatic pressure, food distribution, trench topographic forcing and potential ecological interactions.


Assuntos
Anfípodes/classificação , Anfípodes/genética , DNA Mitocondrial/genética , Variação Genética/genética , RNA Ribossômico 16S/genética , Animais , Ecossistema , Fluxo Gênico , Oceano Pacífico , População/genética
3.
Mar Pollut Bull ; 143: 33-41, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31789163

RESUMO

The effects of CO2-related acidification on two crustacean populations, the isopod Cyathura carinata and the amphipod Elasmopus rapax, were studied. Three pH levels were tested: artificial seawater without CO2 injection and two levels of reduced pH. Even though RNA:DNA ratio was reduced for both species, no statistical significant differences were found between the control and the treatments. Both species experienced a reduction in survivorship, longevity and the body length of surviving animals; although the impairment observed in E. rapax was more severe than in C. carinata. The long life span isopod and the short life span amphipod experienced a high degree of impairment in the reproduction, likely due to the reallocation of resources from reproduction to body maintenance and increasing survival by postponing the brood production. Regardless of the underlying processes and the energetic pathways, both experienced failure to reproduce, which could lead to the local extinction of these species.


Assuntos
Anfípodes/fisiologia , Dióxido de Carbono , Isópodes/fisiologia , Reprodução/fisiologia , Água do Mar/química , Anfípodes/anatomia & histologia , Anfípodes/genética , Animais , Tamanho Corporal , Ecotoxicologia , Sedimentos Geológicos/química , Concentração de Íons de Hidrogênio , Isópodes/anatomia & histologia , Isópodes/genética , Mortalidade , Especificidade da Espécie
4.
Ecotoxicol Environ Saf ; 186: 109764, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31610356

RESUMO

Crustaceans have been designated as internationally important model organisms in the development of environmental radioprotection measures. Despite the known sensitivity of sperm to ionizing radiation, the impacts of chronic radiation exposure on male fertility in crustaceans have not been studied. For the first time, the present study aimed to assess the impacts of chronic radiation exposure on male fertility, sperm DNA damage and concomitant impacts on breeding in two amphipod crustaceans. Echinogammarus marinus and Gammarus pulex (male fertility only) were exposed to phosphorus-32 at dose rates of 0, 0.1, 1 and 10 mGy/d and sperm parameters, DNA damage and knock-on impacts on breeding were assessed. Sperm quality parameters and DNA damage were assessed using a fluorescent staining method and single cell gel electrophoresis respectively. Concomitant effects of male exposure to radiation on fecundity were determined by pairing phosphorus-32 exposed males to unexposed sexually mature females. In E. marinus, a statistically significant reduction of 9 and 11% in the quality of sperm was recorded at dose rates of 1 and 10 mGy/d respectively, with no significant effects recorded on sperm counts. Conversely in the freshwater G. pulex, no significant impact of radiation on sperm quantity or quality was recorded. For E. marinus, a statistically significant increase in DNA damage was recorded at doses of 10 mGy/d. Reduced fecundity and an increase in the frequency of abnormal embryos was recorded in female E. marinus breeding with males exposed to radiation. These findings suggest sperm quality may be a sensitive indicator of radiation exposure in invertebrates with potential impacts on the unexposed embryo, though unclear dose-response and differences between two closely related species necessitate further study before robust conclusions can be drawn.


Assuntos
Anfípodes/efeitos da radiação , Dano ao DNA , Radiação Ionizante , Espermatozoides/efeitos da radiação , Anfípodes/genética , Anfípodes/crescimento & desenvolvimento , Animais , Feminino , Fertilidade/efeitos da radiação , Água Doce , Masculino , Água do Mar , Espermatozoides/patologia
5.
BMC Genomics ; 20(1): 712, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31519144

RESUMO

BACKGROUND: Lake Baikal is one of the oldest freshwater lakes and has constituted a stable environment for millions of years, in stark contrast to small, transient bodies of water in its immediate vicinity. A highly diverse endemic endemic amphipod fauna is found in one, but not the other habitat. We ask here whether differences in stress response can explain the immiscibility barrier between Lake Baikal and non-Baikal faunas. To this end, we conducted exposure experiments to increased temperature and the toxic heavy metal cadmium as stressors. RESULTS: Here we obtained high-quality de novo transcriptome assemblies, covering mutiple conditions, of three amphipod species, and compared their transcriptomic stress responses. Two of these species, Eulimnogammarus verrucosus and E. cyaneus, are endemic to Lake Baikal, while the Holarctic Gammarus lacustris is a potential invader. CONCLUSIONS: Both Baikal species possess intact stress response systems and respond to elevated temperature with relatively similar changes in their expression profiles. G. lacustris reacts less strongly to the same stressors, possibly because its transcriptome is already perturbed by acclimation conditions.


Assuntos
Anfípodes/genética , Anfípodes/fisiologia , Lagos , Estresse Fisiológico/genética , Transcriptoma , Anfípodes/efeitos dos fármacos , Animais , Cádmio/toxicidade , Geografia , Resposta ao Choque Térmico/genética , Especificidade da Espécie , Estresse Fisiológico/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos
6.
BMC Evol Biol ; 19(1): 138, 2019 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286865

RESUMO

BACKGROUND: The ancient Lake Baikal is characterized by an outstanding diversity of endemic faunas with more than 350 amphipod species and subspecies. We determined the genetic diversity within the endemic littoral amphipod species Eulimnogammarus verrucosus, E. cyaneus and E. vittatus and investigated whether within those species genetically separate populations occur across Lake Baikal. Gammarus lacustris from water bodies in the Baikal area was examined for comparison. RESULTS: Genetic diversities within a species were determined based on fragments of cytochrome c oxidase I (COI) and for E. verrucosus additionally of 18S rDNA. Highly location-specific haplogroups of E. verrucosus and E. vittatus were found at the southern and western shores of Baikal that are separated by the Angara River outflow; E. verrucosus from the eastern shore formed a further, clearly distinct haplotype cluster possibly confined by the Selenga River and Angarskiy Sor deltas. The genetic diversities within these haplogroups were lower than between the different haplogroups. Intraspecific genetic diversities within E. verrucosus and E. vittatus with 13 and 10%, respectively, were similar to interspecies differences indicating the occurrence of cryptic, morphologically highly similar species; for E. verrucosus this was confirmed with 18S rDNA. The haplotypes of E. cyaneus and G. lacustris specimens were with intraspecific genetic distances of 3 and 2%, respectively, more homogeneous indicating no or only recent disruption of gene flow of E. cyaneus across Baikal and recent colonization of water bodies around Baikal by G. lacustris. CONCLUSIONS: Our finding of separation of subgroups of Baikal endemic amphipods to different degrees points to a species-specific ability of dispersal across areas with adverse conditions and to potential geographical dispersal barriers in Lake Baikal.


Assuntos
Anfípodes/genética , Especiação Genética , Lagos , Distribuição Animal , Animais , Variação Genética , Geografia
7.
Zootaxa ; 4544(3): 395-406, 2019 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-30647247

RESUMO

A new species of the maerid amphipod, Elasmopus nkjaf, from Miyako Island, Ryukyu Islands, Japan, is named and described. Additionally, nucleotide sequences of nuclear 28S ribosomal RNA and histone H3 as well as mitochondrial cytochrome c oxidase subunit I and 16S ribosomal RNA from its holotype and paratype were determined. Elasmopus nkjaf sp. nov. belongs to the rapax-group, and distinguished from the other rapax-group species by long setae on ventral margin of epimeral plate 3, gland cone of peduncular article 2 of antenna 2 not reaching to end of peduncular article 3, propodus of gnathopod 1 facially setose, length of propodus of male gnathopod 2 shorter than 3 times as long as length of carpus, medial face of propodus of male gnathopod 2 shallowly hollowed, posterior margin of epimeral plate 3 without denticles. A key to the species of Elasmopus species occurring Japanese and adjacent waters is provided.


Assuntos
Anfípodes , RNA Ribossômico 28S , Anfípodes/genética , Animais , Ilhas , Japão , Masculino , RNA Ribossômico 16S
8.
Mol Phylogenet Evol ; 132: 53-66, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30476552

RESUMO

Amphipods of the genus Gammarus are a vital component of macrozoobenthic communities in European inland and coastal, marine and brackish waters of the Mediterranean and the Black Sea. Exceptional levels of cryptic diversity have been revealed for several widespread freshwater Gammarus species in Europe. No comprehensive assessment has yet been made for brackishwater counterparts, such as Gammarus aequicauda and G. insensibilis, which are among the most widely dispersed members of the so-called "G. locusta group" in the Mediterranean and in the Black Sea. Here we probe the diversity of these morphospecies examining the partitioning of mtDNA and nDNA across multiple populations along their distribution range and discuss it within the regional paleogeographic framework. We gathered molecular data from a collection of 166 individuals of G. aequicauda and G. insensibilis from 47 locations along their distribution range in the Mediterranean including the Black Sea. They were amplified for both mitochondrial COI and 16S rRNA as well as the nuclear 28S rRNA. All five MOTU delimitation methods (ABGD, BIN, bPTP, GMYC single and multiple threshold models) applied revealed deep divergence between Black Sea and Mediterranean populations in both G. aequicauda and G. insensibilis. There were eight distinct MOTUs delimited for G. aequicauda (6-18% K2P) and 4 MOTUs for G. insensibilis (4-14% K2P). No sympatric MOTUs were detected throughout their distribution range. Multimarker time-calibrated phylogeny indicated that divergence of both G. aequicauda and G. insensibilis species complexes started already in the late Oligocene/early Miocene with the split between clades inhabiting eastern and western part of the Mediterranean occurring in both species at the similar time. Our results indicate a high cryptic diversity within Mediterranean brackishwater Gammarus, similar to that observed for freshwater counterparts. Moreover, the phylogenetic history combined with the current geographic distribution indicate that the evolution of both studied Gammarus morphogroups has been strongly connected with the geological events in the Mediterranean Basin and it reflect the turbulent history of the area.


Assuntos
Anfípodes/genética , Variação Genética , Filogeografia , Animais , Teorema de Bayes , Ecossistema , Geografia , Haplótipos/genética , Região do Mediterrâneo , Filogenia , Especificidade da Espécie
9.
Mol Ecol ; 28(2): 232-249, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30276912

RESUMO

A thorough understanding of ecological networks relies on comprehensive information on trophic relationships among species. Since unpicking the diet of many organisms is unattainable using traditional morphology-based approaches, the application of high-throughput sequencing methods represents a rapid and powerful way forward. Here, we assessed the application of DNA metabarcoding with nearly universal primers for the mitochondrial marker cytochrome c oxidase I in defining the trophic ecology of adult brown shrimp, Crangon crangon, in six European estuaries. The exact trophic role of this abundant and widespread coastal benthic species is somewhat controversial, while information on geographical variation remains scant. Results revealed a highly opportunistic behaviour. Shrimp stomach contents contained hundreds of taxa (>1,000 molecular operational taxonomic units), of which 291 were identified as distinct species, belonging to 35 phyla. Only twenty ascertained species had a mean relative abundance of more than 0.5%. Predominant species included other abundant coastal and estuarine taxa, including the shore crab Carcinus maenas and the amphipod Corophium volutator. Jacobs' selectivity index estimates based on DNA extracted from both shrimp stomachs and sediment samples were used to assess the shrimp's trophic niche indicating a generalist diet, dominated by crustaceans, polychaetes and fish. Spatial variation in diet composition, at regional and local scales, confirmed the highly flexible nature of this trophic opportunist. Furthermore, the detection of a prevalent, possibly endoparasitic fungus (Purpureocillium lilacinum) in the shrimp's stomach demonstrates the wide range of questions that can be addressed using metabarcoding, towards a more robust reconstruction of ecological networks.


Assuntos
Braquiúros/fisiologia , Código de Barras de DNA Taxonômico , Ecologia , Monitoramento Ambiental , Anfípodes/genética , Anfípodes/fisiologia , Animais , Braquiúros/química , DNA/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Estuários , Comportamento Alimentar , Peixes , Conteúdo Gastrointestinal/química , Filogeografia
10.
PLoS One ; 13(10): e0205556, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30359400

RESUMO

Cave animals provide a unique opportunity to study contrasts in phenotype and life history in strikingly different environments when compared to surface populations, potentially related to natural selection. As such, we compared a permanent cave-living Gammarus lacustris (L.) population with two lake-resident surface populations analyzing morphology (eye- and antennal characters) and life-history (size at maturity, fecundity and egg-size). A part of the cytochrome c oxidase subunit I gene in the mitochondrion (COI) was analyzed to contrast genetic relationship of populations and was compared to sequences in GenBank to assess phylogeography and colonization scenarios. In the cave, a longer life cycle was implied, while surface populations seemed to have a shorter life cycle. Egg size, and size at maturity for both sexes, were larger in the cave than in surface populations, while fecundity was lower in the cave than in surface populations. The cave population had longer first- and second antennae with more articles, longer first- and second peduncles, and fewer ommatidia than surface populations. The cold low-productive cave environment may facilitate different phenotypic and life-history traits than in the warmer and more productive surface lake environments. The trait divergences among cave and surface populations resembles other cave-surface organism comparisons and may support a hypothesis of selection on sensory traits. The cave and Lake Ulvenvann populations grouped together with a sequence from Slovenia (comprising one genetic cluster), while Lake Lille Lauarvann grouped with a sequence from Ukraine (comprising another cluster), which are already recognized phylogenetic clusters. One evolutionary scenario is that the cave and surface populations were colonized postglacially around 9 000-10 000 years ago. We evaluate that an alternative scenario is that the cave was colonized during an interstadial during the last glaciation or earlier during the warm period before onset of the last glaciation.


Assuntos
Anfípodes/anatomia & histologia , Anfípodes/genética , Evolução Biológica , Cavernas , Lagos , Animais , Antenas de Artrópodes/anatomia & histologia , Tamanho Corporal , Olho Composto de Artrópodes/anatomia & histologia , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Fertilidade , Variação Genética , Haplótipos , Masculino , Filogeografia , Caracteres Sexuais , Especificidade da Espécie
11.
Mol Phylogenet Evol ; 127: 988-999, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30004011

RESUMO

The amphi-Atlantic distributions exhibited by many thalassoid stygobiont (obligate subterranean) crustaceans have been explained by fragmentation by plate tectonics of ancestral shallow water marine populations. The amphipod stygobiont genus Pseudoniphargus is distributed across the Mediterranean region but also in the North Atlantic archipelagos of Bermuda, Azores, Madeira and the Canaries. We used species delimitation methods and mitogenome phylogenetic analyses to clarify the species diversity and evolutionary relationships within the genus and timing their diversification. Analyses included samples from the Iberian Peninsula, northern Morocco, the Balearic, Canarian, Azores and Madeira archipelagoes plus Bermuda. In most instances, morphological and molecular-based species delimitation analyses yielded consistent results. Notwithstanding, in a few cases either incipient speciation with no involvement of detectable morphological divergence or species crypticism were the most plausible explanations for the disagreement found between morphological and molecular species delimitations. Phylogenetic analyses based on a robust calibrated mitochondrial tree suggested that Pseudoniphargus lineages have a younger age than for other thalassoid amphipods displaying a disjunct distribution embracing both sides of the Atlantic Ocean. A major split within the family was estimated to occur at the Paleocene, when a lineage from Northern Iberian Peninsula diverged from the rest of pseudoniphargids. Species diversification in the peri-Mediterranean area was deduced to occur in early Miocene to Tortonian times, while in the Atlantic islands it started in the Pliocene. Our results show that the current distribution pattern of Pseudoniphargus resulted from a complex admix of relatively ancient vicariance events and several episodes of long- distance dispersal.


Assuntos
Anfípodes/genética , Ecossistema , Genoma Mitocondrial , Filogenia , Animais , Sequência de Bases , Teorema de Bayes , Calibragem , Complexo IV da Cadeia de Transporte de Elétrons/genética , Geografia , Funções Verossimilhança , Especificidade da Espécie
12.
Mol Phylogenet Evol ; 127: 746-757, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29908996

RESUMO

Vicariance and dispersal events affect current biodiversity patterns in desert springs. Whether major diversification events are due to environmental changes leading to radiation or due to isolation resulting in relict species is largely unknown. We seek to understand whether the Gammarus pecos species complex underwent major diversification events due to environmental changes in the area leading either to radiation into novel habitats, or formation of relicts due to isolation. Specifically, we tested the hypothesis that Gammarus in the northern Chihuahuan Desert of New Mexico and Texas, USA are descendants of an ancient marine lineage now containing multiple undescribed species. We sequenced a nuclear (28S) and two mitochondrial (16S, COI) genes from gammarid amphipods representing 16 desert springs in the northern Chihuahuan Desert. We estimated phylogenetic relationships, divergence times, and diversification rates of the Gammarus pecos complex. Our results revealed that the region contained two evolutionarily independent lineages: a younger Freshwater Lineage that shared a most-recent-common-ancestor with an older Saline Lineage ∼66.3  MYA (95.6-42.4  MYA). Each spring system generally formed a monophyletic clade based on the concatenated dataset. Freshwater Lineage diversification rates were 2.0-9.8 times higher than rates of the Saline Lineage. A series of post-Cretaceous colonizations by ancestral Gammarus taxa was likely followed by isolation. Paleo-geological, hydrological, and climatic events in the Neogene-to-Quaternary periods (23.03  MYA - present) in western North America promoted allopatric speciation of both lineages. We suggest that Saline Lineage populations include two undescribed Gammarus species, while the Freshwater Lineage shows repetition of fine-scale genetic structure in all major clades suggesting incipient speciation. Such ongoing speciation suggests that this region will continue to be a biodiversity hotspot for amphipods and other freshwater taxa.


Assuntos
Anfípodes/fisiologia , Biodiversidade , Água Doce , Isolamento Social , Anfípodes/genética , Animais , Sequência de Bases , Teorema de Bayes , Complexo IV da Cadeia de Transporte de Elétrons/genética , Variação Genética , Genética Populacional , Geografia , Modelos Teóricos , Paleontologia , Filogenia , Salinidade , Texas
13.
Integr Comp Biol ; 58(3): 452-464, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29931265

RESUMO

Animals that inhabit subterranean environments often undergo various distinct phenotypic modifications (referred to as "troglomorphy") as they transition to life in perpetual darkness. However, the molecular basis behind troglomorphy remains poorly understood, particularly in regards to the mechanisms involved in the reduction and/or loss of traits at the transcriptomic level. In this study, we investigate the transcriptional basis behind vision loss in populations of cave-dwelling crustaceans. We employ phylogenetic and transcriptomic methods on surface and cave-adapted populations of an emerging model species for biospeleology, the isopod Asellus aquaticus (Linnaeus, 1758), and the amphipod Niphargus hrabei S. Karaman, 1932. These two species show contrasting directionality in the surface-cave transition, which positions them as ideal study subjects. Asellus aquaticus is common in surface waters and is only occasionally found in caves, where its populations present different degrees of eye reduction and pigmentation. On the other hand, the eyeless N. hrabei has successfully colonized surface environments despite belonging to an almost exclusively cave-dwelling genus. By sequencing and assembling robust de novo transcriptomes we characterized differences in visual genes and pathways among surface and cave populations of the aforementioned species. Our results indicate that despite having reduced eyes, recent cave colonizer A. aquaticus is still capable of expressing functional visual opsins and major components of the phototransduction pathway within the cave. Niphargus hrabei, a species with an ancient cave origin, shows no clear indication of being capable of sight. However, the expression of putative functional visual opsins and other phototransduction genes was maintained, which suggests that this eyeless species might be capable of extraocular photoreception. With the present study, we aim to bring forth the Molnár János Cave system as a promising research avenue to improve our understanding of patterns of reduction and loss of vision in caves and other aphotic environments.


Assuntos
Anfípodes/fisiologia , Evolução Molecular , Isópodes/fisiologia , Transcriptoma , Visão Ocular/genética , Anfípodes/genética , Animais , Evolução Biológica , Cavernas , Escuridão , Hungria , Isópodes/genética , Transdução de Sinal Luminoso/genética , Filogenia
14.
Sci Rep ; 8(1): 6893, 2018 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-29720606

RESUMO

Taxonomy plays a central role in biological sciences. It provides a communication system for scientists as it aims to enable correct identification of the studied organisms. As a consequence, species descriptions should seek to include as much available information as possible at species level to follow an integrative concept of 'taxonomics'. Here, we describe the cryptic species Epimeria frankei sp. nov. from the North Sea, and also redescribe its sister species, Epimeria cornigera. The morphological information obtained is substantiated by DNA barcodes and complete nuclear 18S rRNA gene sequences. In addition, we provide, for the first time, full mitochondrial genome data as part of a metazoan species description for a holotype, as well as the neotype. This study represents the first successful implementation of the recently proposed concept of taxonomics, using data from high-throughput technologies for integrative taxonomic studies, allowing the highest level of confidence for both biodiversity and ecological research.


Assuntos
Anfípodes/classificação , Anfípodes/genética , Ecossistema , Anfípodes/anatomia & histologia , Animais , Biodiversidade , Código de Barras de DNA Taxonômico , Genoma Mitocondrial , Genômica/métodos , RNA Ribossômico 18S , RNA de Transferência
15.
PLoS One ; 13(5): e0197174, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29791459

RESUMO

Monitoring the distribution of marine biodiversity is a crucial step to better assess the impacts of global changes. Arctic marine fauna is dominated by amphipods in terms of abundance and biomass. These peracarids are an important marine order of crustaceans but the number of species found in the different Canadian oceans is currently unknown. Furthermore, most species are difficult to identify due to poor taxonomic descriptions and morphological convergence. The aim of this study was to assess the species diversity of marine amphipods in the three Canadian oceans using DNA barcoding. To do so, we produced a database of DNA barcodes of amphipods from the three Canadian Oceans publicly available from the BOLD website to which we added 310 new sequences from the Canadian Arctic Archipelago. We first delimited amphipod species based on barcode gap detection techniques and tree based method (bPTP) and then compared the composition of amphipods among the three oceans in order to assess the influence of past transarctic exchanges on Arctic diversity. Our analysis of 2309 sequences which represent more than 250 provisional species revealed a high connectivity between the Atlantic and Arctic Oceans. Our results also suggest that a single threshold to delimitate species is not suitable for amphipods. This study highlights the challenges involved in species delimitation and the need to obtain complete barcoding inventories in marine invertebrates.


Assuntos
Anfípodes/genética , Anfípodes/classificação , Animais , Regiões Árticas , Biodiversidade , Canadá , Tipagem Molecular , Oceanos e Mares , Filogenia
16.
PLoS One ; 13(4): e0195529, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29624607

RESUMO

The use of environmental DNA (eDNA) as a species detection tool is attracting attention from both scientific and applied fields, especially for detecting invasive or rare species. In order to use eDNA as an efficient and reliable tool, however, we need to understand its origin and state as well as factors affecting its degradation. Various biotic and abiotic environmental factors have been proposed to affect degradation of eDNA in aquatic environments and thus to influence detection rates of species. Here, we were interested in two of them, namely UV light, which can break down DNA, and the presence of filter feeders, which can remove DNA and DNA-bound particles. A few, mostly laboratory-based studies have found minor effects of UVB on the degradation of eDNA. Ultraviolet A radiation (UVA), however, has been neglected although it also causes DNA lesions and is 10- to 100-fold more prevalent than UVB when reaching the earth's surface. Filter feeders are common in aquatic ecosystem, but their effects on eDNA has hitherto been ignored. We conducted a full-factorial aquatic mesocosm experiment under near-natural outdoor conditions manipulating UV radiation as well as the presence of Dreissena polymorpha, a strong filter feeder capable of filtering cells or organelles containing DNA. Surprisingly, we found that neither UV radiation nor the presence of the filter feeder affected eDNA-based detection rates of macroinvertebrates, even though the experiment took place in summer when UV radiation intensity and filtration activity is high for the chosen experimental site and conditions. These results, in combination with studies from marine or laboratory settings finding no effect of sunlight and its UV components on the detectability of eDNA, suggest that eDNA based species assessments could be relatively robust with respect to our two factors studied.


Assuntos
Organismos Aquáticos/genética , DNA/genética , DNA/efeitos da radiação , Anfípodes/genética , Animais , DNA/análise , Primers do DNA/genética , Dreissena/genética , Ecossistema , Isópodes/genética , Reação em Cadeia da Polimerase , Caramujos/genética , Especificidade da Espécie , Luz Solar , Raios Ultravioleta
17.
Biosci Biotechnol Biochem ; 82(7): 1123-1133, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29623763

RESUMO

Hirondellea species are common inhabitants in the hadal region deeper than 7,000 m. We found that Hirondellea gigas thrived in the Challenger Deep possessed polysaccharide hydrolases as digestive enzymes. To obtain various enzymes of other H. gigas, we captured amphipods from the Japan Trench, and Izu-Ogasawara (Bonin) Trench. A phylogenetic analysis based on the cytochrome oxidase I gene showed close relationships among amphipods, despite the geographic distance between the localities. However, several differences in enzymatic properties were observed in these H. gigas specimens. We also carried out RNA sequencing of H. gigas from the Izu-Ogasawara Trench. The cellulase gene of H. gigas was highly homologous to cellobiohydrolase of Glucosyl Hydrolase family 7 (GH7). On the other hand, enzymatic properties of H. gigas's cellulase were different from those of typical GH7 cellobiohydrolase. Thus, these results indicate that hadal-zone amphipod can be good candidates as the new enzyme resource.


Assuntos
Anfípodes/enzimologia , Hidrolases/metabolismo , Polissacarídeos/metabolismo , Anfípodes/classificação , Anfípodes/genética , Animais , Organismos Aquáticos , Celulase/genética , Celulase/metabolismo , Celulose 1,4-beta-Celobiosidase/genética , Celulose 1,4-beta-Celobiosidase/metabolismo , Cinética , Mutação , Filogenia , Água do Mar , Análise de Sequência de RNA , Especificidade por Substrato
18.
Sci Rep ; 8(1): 3793, 2018 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-29491422

RESUMO

Taking advantage of a large transcriptomic dataset recently obtained in the sentinel crustacean amphipod Gammarus fossarum, we developed an approach based on sequence similarity and phylogenetic reconstruction to identify key players involved in the endocrine regulation of G. fossarum. Our work identified three genes of interest: the nuclear receptors RXR and E75, and the regulator broad-complex (BR). Their involvement in the regulation of molting and reproduction, along with their sensitivity to chemical contamination were experimentally assessed by studying gene expression during the female reproductive cycle, and after laboratory exposure to model endocrine disrupting compounds (EDCs): pyriproxyfen, tebufenozide and piperonyl butoxide. RXR expression suggested a role of this gene in ecdysis and post-molting processes. E75 presented two expression peaks that suggested a role in vitellogenesis, and molting. BR expression showed no variation during molting/reproductive cycle. After exposure to the three EDCs, a strong inhibition of the inter-molt E75 peak was observed with tebufenozide, and an induction of RXR after exposure to pyriproxyfen and piperonyl butoxide. These results confirm the implication of RXR and E75 in hormonal regulation of female reproductive cycles in G. fossarum and their sensitivity towards EDCs opens the possibility of using them as specific endocrine disruption biomarkers.


Assuntos
Anfípodes/metabolismo , Biomarcadores/metabolismo , Ecdisona/farmacologia , Disruptores Endócrinos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Espécies Sentinelas/metabolismo , Anfípodes/genética , Animais , Perfilação da Expressão Gênica , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores X Retinoide/genética , Receptores X Retinoide/metabolismo , Espécies Sentinelas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
19.
Mol Phylogenet Evol ; 125: 232-242, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29545110

RESUMO

Ancient lakes are renowned for their exceptional diversity of endemic species. As model systems for the study of sympatric speciation, it is necessary to understand whether a given hypothesized species flock is of monophyletic or polyphyletic origin. Here, we present the first molecular characterization of the Hyalella (Crustacea: Amphipoda) species complex of Lake Titicaca, using COI and 28S DNA sequences, including samples from the connected Small and Large Lakes that comprise Lake Titicaca as well as from a broader survey of southern South American sites. At least five evolutionarily distant lineages are present within Lake Titicaca, which were estimated to have diverged from one another 12-20 MYA. These major lineages are dispersed throughout the broader South American Hyalella phylogeny, with each lineage representing at least one independent colonization of the lake. Moreover, complex genetic relationships are revealed between Lake Titicaca individuals and those from surrounding water bodies, which may be explained by repeated dispersal into and out of the lake, combined with parallel intralacustrine diversification within two separate clades. Although further work in deeper waters will be required to determine the number of species present and modes of diversification, our results strongly indicate that this amphipod species cloud is polyphyletic with a complex geographic history.


Assuntos
Anfípodes/fisiologia , Lagos , Anfípodes/genética , Animais , Teorema de Bayes , Biodiversidade , Intervalos de Confiança , Especiação Genética , Geografia , Funções Verossimilhança , Filogenia , Especificidade da Espécie , Simpatria , Fatores de Tempo
20.
Mar Genomics ; 38: 67-88, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29395622

RESUMO

Due to its sensitivity to many environmental and anthropogenic stressors, including a wide range of chemical compounds, Hyalella azteca, a freshwater amphipod, has emerged as one of the most commonly used invertebrates for ecotoxicological assessment.Peptidergic signaling systems are key components in the control of organism-environment interactions, and there is a growing literature suggesting that they are targets of a number of aquatic toxicants.Interestingly, and despite its model species status in the field of ecotoxicology, little is known about the peptide hormones of H. azteca.Here, a transcriptome was produced for this species using the de novo assembler Trinity and mined for sequences encoding putative peptide precursors; the transcriptome was assembled from 460,291,636 raw reads and consists of 133,486 unique transcripts.Seventy-six sequences encoding peptide pre/preprohormones were identified from this transcriptome, allowing for the prediction of 202 distinct peptides, which included members of the allatostatin A, allatostatin B, allatostatin C, allatotropin, bursicon, CCHamide, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone/molt-inhibiting hormone, ecdysis-triggering hormone, eclosion hormone, elevenin, FMRFamide-like peptide, glycoprotein hormone, GSEFLamide, inotocin, leucokinin, myosuppressin, neuropeptide F, orcokinin, orcomyotropin, pigment dispersing hormone, proctolin, pyrokinin, red pigment concentrating hormone, RYamide, short neuropeptide F, SIFamide, sulfakinin, tachykinin-related peptide and trissin families.These peptides expand the known peptidome for H. azteca approximately nine-fold, forming a strong foundation for future studies of peptidergic control, including disruption by aquatic toxicants, in this important ecotoxicological model.


Assuntos
Anfípodes/genética , Proteínas de Artrópodes/genética , Peptídeos/genética , Transcriptoma , Animais
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