Free-living Nematodes of Brazilian Oceanic Islands: Revealing the Richness in the most isolated marine habitats of Brazil

Flatworms of the Order Polycladida are a group of free-living invertebrates found in a diversity of marine habitats, with over 800 species described worldwide. Marine flatworms are a conspicuous component of Australia’s marine fauna yet have received little attention. Less than 30 scientific articles have been published on Australian marine flatworms since 1855, of which only nine include species from southeastern Australia. Here, the biodiversity and distribution of species belonging to the Order Polycladida inhabiting intertidal rocky beaches in southeastern Australian waters were identified and analysed. Sampling was conducted at low tide along the coasts of New South Wales and Victoria. Collected samples were serially sectioned for comparative anatomical studies, and tissue was removed from each individual for molecular sequencing and analyses. Both nuclear and mitochondrial DNA sequences were obtained and used as an additional source of evidence for the description of new species as well as providing further insight into the phylogenetic relationships between them. A total of 20 species, six of which are new (e.g., Eulatocestus australis sp. nov.), and a new genus (Parabolia gen. nov.) have been described, as well as two new records for Australia (e.g., Stylochoplana clara Kato, 1937) have been identified increasing our knowledge of this important component of the Australian marine biota.

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Biodiversity of free-living marine nematodes on the coast of Brazil: a review

Zootaxa ◽

10.11646/zootaxa.2568.1.2 ◽

2010 ◽

Vol 2568 (1) ◽

pp. 39 ◽

Cited By ~ 12

Author(s):

VIRÁG VENEKEY ◽

VERÔNICA G. FONSECA-GENEVOIS ◽

PAULO J. P. SANTOS

Keyword(s):

Sandy Beaches ◽

Oceanic Islands ◽

Taxonomic Composition ◽

Artificial Substrates ◽

Rocky Shores ◽

Coastal Habitats ◽

Free Living ◽

Generic Composition ◽

Faunal List ◽

First Time

The taxonomic richness of the marine Nematoda in coastal habitats of Brazil and similarities in generic composition among them are analysed. A complete faunal list is presented, containing 11 orders, 59 families, 294 genera and 231 species, among which 1 family, 10 genera and 87 species were discovered for the first time in Brazil. Seven habitats were considered (sandy beaches, estuaries, phytal, oceanic islands, beach rocks, salt works and artificial substrates): sandy beaches had the greatest generic richness (241), followed by estuaries (142) and the phytal environment (126). Taxonomic composition was similar to that of other coastal habitats sampled worldwide, with Chromadoridae and Xyalidae the most representative families. The three major habitats (beaches, rocky shores and estuaries), showed statistically significant differences in faunas. Estuaries were the most uniform in composition.

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Draft Genome Sequence of a Harveyi Clade Bacterium Isolated from Lolliguncula brevis Squid

Microbiology Resource Announcements ◽

10.1128/mra.00078-20 ◽

2020 ◽

Vol 9 (8) ◽

Author(s):

Alecia N. Septer ◽

Lauren Speare ◽

Collin K. Coleman ◽

Stephanie Smith ◽

Coby Dorsey ◽

...

Keyword(s):

Genome Sequence ◽

Draft Genome ◽

Draft Genome Sequence ◽

Free Living ◽

Content Type ◽

Marine Habitats ◽

Lolliguncula Brevis

Vibrio species of the Harveyi clade are commonly found in free-living and host-associated marine habitats. Here, we report the draft genome sequence for a Harveyi clade bacterium, Vibrio sp. strain LB10LO1, which was isolated from the Atlantic brief squid Lolliguncula brevis.

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Spatiotemporal Dynamics of Free-Living and Particle-Associated Vibrio Communities in the Northern Chinese Marginal Seas

Applied and Environmental Microbiology ◽

10.1128/aem.00217-19 ◽

2019 ◽

Vol 85 (9) ◽

Cited By ~ 12

Author(s):

Jinchang Liang ◽

Jiwen Liu ◽

Xiaolei Wang ◽

Heyu Lin ◽

Jingli Liu ◽

...

Keyword(s):

Environmental Factors ◽

Pore Size ◽

Spatiotemporal Dynamics ◽

Free Living ◽

Content Type ◽

Marginal Seas ◽

Filter Membrane ◽

Marine Habitats ◽

Northern Chinese ◽

Chinese Marginal Seas

ABSTRACT Vibrio species are associated with human health and play important roles in the carbon cycle. The interest in the Vibrio ecology in marine pelagic environments has increased in recent years, and the correlations between the Vibrio community structure and various environmental factors have been demonstrated. However, the identification of planktonic Vibrio species and their relationship with particulate matter are unclear. Here, we elucidated the spatiotemporal dynamics of Vibrio diversity and in relation to environmental factors in the northern Chinese marginal seas, which feature complex and ever-changing environmental conditions. Vibrio abundance derived from quantitative PCR analysis was higher in summer (∼1.4 × 106 copies liter−1) than in winter (∼1.9 × 105 copies liter−1). Interestingly, the average amount of free-living (on a 0.22-μm-pore-size filter membrane) Vibrio was higher (∼3.89 times) than that of particle-associated Vibrio (on a 3-μm-pore-size filter membrane), making it likely that the preferential lifestyle of the planktonic Vibrio community was free living. Shifts in Vibrio community composition identified by high-throughput amplicon sequencing of the Vibrio-specific 16S rRNA gene were observed at both spatial and temporal scales, which were mainly driven by temperature, dissolved oxygen, ammonium, salinity, nitrite, and phosphate. The most prominent operational taxonomic units in summer were closely related to Vibrio campbellii and Vibrio caribbeanicus and shifted to those affiliated with Vibrio atlanticus in winter. Our study demonstrated abundant and diverse Vibrio populations in the northern Chinese marginal seas, contributing to a better understanding of their potential ecological roles in these ecosystems. IMPORTANCE The dynamics of Vibrio communities have been shown in many marine habitats that are close to land, including estuary or harbor areas. Here, we investigated the spatiotemporal dynamics of Vibrio populations in the northern Chinese marginal seas, spanning a wide spatial scale. We showed that the abundances of the Vibrio population in the present study were higher than those in most previously studied areas and that Vibrio species are more likely to adopt a free-living lifestyle. Moreover, our results expanded upon previous results by showing a clear shift in the dominant Vibrio species from summer to winter, which was mainly attributable to the reduction in the abundance of dominant species in summer. Overall, this work contributes to the understanding of the ecology of the Vibrio communities in the marginal seas.

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Culturing and environmental DNA sequencing uncover hidden kinetoplastid biodiversity and a major marine clade within ancestrally freshwater Neobodo designis

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.63606-0 ◽

2005 ◽

Vol 55 (6) ◽

pp. 2605-2621 ◽

Cited By ~ 65

Author(s):

Sophie von der Heyden ◽

Thomas Cavalier-Smith

Keyword(s):

Genetic Diversity ◽

Dna Sequences ◽

18S Rrna ◽

Environmental Dna ◽

Pcr Primers ◽

Rrna Genes ◽

Rrna Gene ◽

Free Living ◽

Marine Habitats ◽

18S Rrna Genes

Bodonid flagellates (class Kinetoplastea) are abundant, free-living protozoa in freshwater, soil and marine habitats, with undersampled global biodiversity. To investigate overall bodonid diversity, kinetoplastid-specific PCR primers were used to amplify and sequence 18S rRNA genes from DNA extracted from 16 diverse environmental samples; of 39 different kinetoplastid sequences, 35 belong to the subclass Metakinetoplastina, where most group with the genus Neobodo or the species Bodo saltans, whilst four group with the subclass Prokinetoplastina (Ichthyobodo). To study divergence between freshwater and marine members of the genus Neobodo, 26 new Neobodo designis strains were cultured and their 18S rRNA genes were sequenced. It is shown that the morphospecies N. designis is a remarkably ancient species complex with a major marine clade nested among older freshwater clades, suggesting that these lineages were constrained physiologically from moving between these environments for most of their long history. Other major bodonid clades show less-deep separation between marine and freshwater strains, but have extensive genetic diversity within all lineages and an apparently biogeographically distinct distribution of B. saltans subclades. Clade-specific 18S rRNA gene primers were used for two N. designis subclades to test their global distribution and genetic diversity. The non-overlap between environmental DNA sequences and those from cultures suggests that there are hundreds, possibly thousands, of different rRNA gene sequences of free-living bodonids globally.

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Single-cell genomics unveiled a cryptic cyanobacterial lineage with a worldwide distribution hidden by a dinoflagellate host

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1902538116 ◽

2019 ◽

Vol 116 (32) ◽

pp. 15973-15978 ◽

Cited By ~ 6

Author(s):

Takuro Nakayama ◽

Mami Nomura ◽

Yoshihito Takano ◽

Goro Tanifuji ◽

Kogiku Shiba ◽

...

Keyword(s):

Phylogenetic Analyses ◽

Marine Cyanobacteria ◽

Symbiotic Association ◽

Free Living ◽

Symbiotic Relationships ◽

Worldwide Distribution ◽

Marine Habitats ◽

Ecological Features ◽

Wide Range ◽

A Cell

Cyanobacteria are one of the most important contributors to oceanic primary production and survive in a wide range of marine habitats. Much effort has been made to understand their ecological features, diversity, and evolution, based mainly on data from free-living cyanobacterial species. In addition, symbiosis has emerged as an important lifestyle of oceanic microbes and increasing knowledge of cyanobacteria in symbiotic relationships with unicellular eukaryotes suggests their significance in understanding the global oceanic ecosystem. However, detailed characteristics of these cyanobacteria remain poorly described. To gain better insight into marine cyanobacteria in symbiosis, we sequenced the genome of cyanobacteria collected from a cell of a pelagic dinoflagellate that is known to host cyanobacterial symbionts within a specialized chamber. Phylogenetic analyses using the genome sequence revealed that the cyanobacterium represents an underdescribed lineage within an extensively studied, ecologically important group of marine cyanobacteria. Metagenomic analyses demonstrated that this cyanobacterial lineage is globally distributed and strictly coexists with its host dinoflagellates, suggesting that the intimate symbiotic association allowed the cyanobacteria to escape from previous metagenomic studies. Furthermore, a comparative analysis of the protein repertoire with related species indicated that the lineage has independently undergone reductive genome evolution to a similar extent as Prochlorococcus, which has the most reduced genomes among free-living cyanobacteria. Discovery of this cyanobacterial lineage, hidden by its symbiotic lifestyle, provides crucial insights into the diversity, ecology, and evolution of marine cyanobacteria and suggests the existence of other undiscovered cryptic cyanobacterial lineages.

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Species Radiations in the Sea: What the Flock?

Journal of Heredity ◽

10.1093/jhered/esz075 ◽

2020 ◽

Vol 111 (1) ◽

pp. 70-83 ◽

Cited By ~ 4

Author(s):

Brian W Bowen ◽

Zac H Forsman ◽

Jonathan L Whitney ◽

Anuschka Faucci ◽

Mykle Hoban ◽

...

Keyword(s):

Marine Species ◽

Oceanic Islands ◽

Eastern Africa ◽

Dispersal Ability ◽

Species Dispersal ◽

Marine Fauna ◽

Marine Habitats ◽

Pelagic Larvae ◽

Multiple Species ◽

Species Flocks

Abstract Species flocks are proliferations of closely-related species, usually after colonization of depauperate habitat. These radiations are abundant on oceanic islands and in ancient freshwater lakes, but rare in marine habitats. This contrast is well documented in the Hawaiian Archipelago, where terrestrial examples include the speciose silverswords (sunflower family Asteraceae), Drosophila fruit flies, and honeycreepers (passerine birds), all derived from one or a few ancestral lineages. The marine fauna of Hawaiʻi is also the product of rare colonization events, but these colonizations usually yield only one species. Dispersal ability is key to understanding this evolutionary inequity. While terrestrial fauna rarely colonize between oceanic islands, marine fauna with pelagic larvae can make this leap in every generation. An informative exception is the marine fauna that lack a pelagic larval stage. These low-dispersal species emulate a “terrestrial” mode of reproduction (brooding, viviparity, crawl-away larvae), yielding marine species flocks in scattered locations around the world. Elsewhere, aquatic species flocks are concentrated in specific geographic settings, including the ancient lakes of Baikal (Siberia) and Tanganyika (eastern Africa), and Antarctica. These locations host multiple species flocks across a broad taxonomic spectrum, indicating a unifying evolutionary phenomenon. Hence marine species flocks can be singular cases that arise due to restricted dispersal or other intrinsic features, or they can be geographically clustered, promoted by extrinsic ecological circumstances. Here, we review and contrast intrinsic cases of species flocks in individual taxa, and extrinsic cases of geological/ecological opportunity, to elucidate the processes of species radiations.

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Marine Bacteria Display Different Escape Mechanisms When Facing Their Protozoan Predators

Microorganisms ◽

10.3390/microorganisms8121982 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1982

Author(s):

Richard Guillonneau ◽

Claudine Baraquet ◽

Maëlle Molmeret

Keyword(s):

Microbial Communities ◽

Marine Bacteria ◽

Close Association ◽

Acanthamoeba Castellanii ◽

Population Level ◽

Free Living ◽

Marine Habitats ◽

Free Living Amoeba ◽

Environmental Bacteria ◽

The Relationship

Free-living amoeba are members of microbial communities such as biofilms in terrestrial, fresh, and marine habitats. Although they are known to live in close association with bacteria in many ecosystems such as biofilms, they are considered to be major bacterial predators in many ecosystems. Little is known on the relationship between protozoa and marine bacteria in microbial communities, more precisely on how bacteria are able survive in environmental niches where these bacterial grazers also live. The objective of this work is to study the interaction between the axenized ubiquitous amoeba Acanthamoeba castellanii and four marine bacteria isolated from immersed biofilm, in order to evaluate if they would be all grazed upon by amoeba or if they would be able to survive in the presence of their predator. At a low bacteria-to-amoeba ratio, we show that each bacterium is phagocytized and follows a singular intracellular path within this host cell, which appears to delay or to prevent bacterial digestion. In particular, one of the bacteria was found in the amoeba nucleolar compartment whereas another strain was expelled from the amoeba in vesicles. We then looked at the fate of the bacteria grown in a higher bacteria-to-amoeba ratio, as a preformed mono- or multi-species biofilm in the presence of A. castellanii. We show that all biofilms were subjected to detachment from the surface in the presence of the amoeba or its supernatant. Overall, these results show that bacteria, when facing the same predator, exhibit a variety of escape mechanisms at the cellular and population level, when we could have expected a simple bacterial grazing. Therefore, this study unravels new insights into the survival of environmental bacteria when facing predators that they could encounter in the same microbial communities.

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Meiofauna and free-living nematodes in volcanic sands of a remote South Atlantic, oceanic island (Trindade, Brazil)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315417001710 ◽

2017 ◽

Vol 98 (8) ◽

pp. 1919-1934 ◽

Cited By ~ 1

Author(s):

T.M.T. Santos ◽

V. Venekey

Keyword(s):

Sandy Beaches ◽

Oceanic Islands ◽

Oceanic Island ◽

Spatial And Temporal Variation ◽

East Atlantic ◽

Free Living ◽

Intertidal Zones ◽

Deposit Feeders ◽

Trindade Island ◽

Meiofaunal Community

This study presents patterns of spatial and temporal variation in the meiofaunal community and nematode associations on the volcanic sandy beaches of Trindade Island, a remote oceanic island in the South-east Atlantic Ocean. Samples were collected in August (rainy season) and December 2014 (dry season) on four beaches (Tartarugas, Parcel, Cabritos and Portugueses) at three zones of the intertidal (high, mid and low). A total of 10 meiofaunal groups were found. Copepods (31%) and nematodes (27%) dominated the meiofauna in all beaches and zones, regardless of the season. Nematodes were comprised mainly of non-selective deposit feeders, with a total of 27 genera from 12 families, with Cyatholaimidae, Xyalidae and Oncholaimidae as the most diverse and abundant. Significant differences were found in the meiofaunal community, as well as in nematode associations, among seasons and intertidal zones but not among beaches. The sediment characteristics were the main drivers regulating the structure of meiobenthic fauna in Trindade Island. Our findings are also compared to other studies focusing on the meiofauna and nematodes of oceanic islands with carbonate and volcanic sediments; the major patterns are herein presented.

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Ultrastructure of neuromuscular relationships in the canine heartworm (dirofilaria immitis)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143018 ◽

1986 ◽

Vol 44 ◽

pp. 278-279

Author(s):

W. L. Steffens ◽

Nancy B. Roberts ◽

J. M. Bowen

Keyword(s):

Dirofilaria Immitis ◽

Domestic Dogs ◽

Structural Description ◽

Pharmacological Effects ◽

Free Living ◽

Canine Heartworm ◽

The World ◽

Synaptic Region ◽

Muscle Innervation ◽

Insight Into

The canine heartworm is a common and serious nematode parasite of domestic dogs in many parts of the world. Although nematode neuroanatomy is fairly well documented, the emphasis has been on sensory anatomy and primarily in free-living soil species and ascarids. Lee and Miller reported on the muscular anatomy in the heartworm, but provided little insight into the peripheral nervous system or myoneural relationships. The classical fine-structural description of nematode muscle innervation is Rosenbluth's earlier work in Ascaris. Since the pharmacological effects of some nematacides currently being developed are neuromuscular in nature, a better understanding of heartworm myoneural anatomy, particularly in reference to the synaptic region is warranted.

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