The reproductive cycle and development of Crepipatella fecunda (Gastropoda: Calyptraeidae) from southern Chile

2005 ◽  
Vol 85 (1) ◽  
pp. 157-161 ◽  
Author(s):  
O.R. Chaparro ◽  
C.L. Saldivia ◽  
S.V. Pereda ◽  
C.J. Segura ◽  
Y.A. Montiel ◽  
...  
Keyword(s):  
Shell Length ◽  
Morphological Development ◽  
Brooding Female ◽  
Southern Chile ◽  
Free Living ◽  
Crepidula Fornicata ◽  
Planktotrophic Larvae ◽  
Mode Of Development ◽  
Shed Light ◽  
Pelagic Stage

Crepipatella fecunda is a benthic, primarily suspension-feeding gastropod that occurs in great abundance along the Chilean coast. It is a protandrous species whose reproduction involves brooding of an encapsulated embryonic stage followed by the release of free-living planktotrophic larvae. Because its close sister species, C. dilatata, co-occurs with C. fecunda, understanding the details of reproduction in this species might shed light on differences in reproductive features that correlate with divergences in mode of development. In southern Chile, brooding occurs throughout the year except for May and June, and each female produces 3–7 broods. The smallest brooding female was 28·2 mm in shell length and the largest was 56·3 mm. All full-grown eggs from the ovary are deposited at one time in a single brood, and only smaller oocytes remain in the gonad after the female finishes ovopositing. Those females that host pinnotherid crabs do not deposit eggs. All the eggs develop into embryos whose intracapsular development is similar to Crepidula fornicata and Crepipatella lingulata. Planktotrophic larvae hatch at a mean shell length of 329·5 μm (SD=27·09) after 4–5 weeks. During the pelagic stage the shell and velum of the larvae grow, but little other morphological development is visible externally. The pelagic stage lasts for 15–16 days at 17°C, during which the larvae grow ∼20·7 μm d−1. Observations of cultured larvae and protoconchs of field-collected juveniles show that settlement occurs when the larvae reach a shell-length of 650 μm (SD=28·3 μm).

The relationship of larval shell morphology to mode of development in marine prosobranch gastropods

1990 ◽  
Vol 70 (3) ◽  
pp. 611-637 ◽  
Author(s):  
Gail M. Lima ◽  
Richard A. Lutz
Keyword(s):  
Shell Morphology ◽  
Larval Shell ◽  
Crepidula Fornicata ◽  
Busycon Canaliculatum ◽  
Littorina Obtusata ◽  
Urosalpinx Cinerea ◽  
Planktotrophic Larvae ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

The larval shell of molluscs contains a preserved record of the organism's growth and developmental history. Many investigators have utilized the information recorded in the larval shell morphology to infer mode of development.Marine prosobranch gastropods were collected from intertidal sites from Maine to Florida and were cultured in the laboratory. Scanning electron microscopy was used to document the relationship of larval shell morphology to development. Four species with planktotrophic larvae, Crepidula fornicata, Crepidula plana, Cerithium atratum and Ilyanassa obsoleta, and four species with non-planktotrophic development, Crepidula convexa, Littorina obtusata, Busycon canaliculatum and Urosalpinx cinerea, were successfully reared through metamorphosis.

The missing links: larval and post-larval development of the ascoglossan opisthobranch Elysia viridis

2000 ◽  
Vol 80 (6) ◽  
pp. 1087-1094 ◽  
Author(s):  
Cynthia D. Trowbridge
Keyword(s):  
Larval Development ◽  
Growth Rates ◽  
Shell Length ◽  
Larval Growth ◽  
Model Organism ◽  
Larval Life ◽  
Codium Fragile ◽  
Planktotrophic Larvae ◽  
Algal Diet ◽  
Better Than

The stenophagous ascoglossan (=sacoglossan) opisthobranch Elysia viridis has long been a model organism for the study of endosymbiosis or kleptoplasty as well as one of the few herbivores to consume the introduced green macroalga Codium fragile on European shores. Larval and post-larval dynamics of the ascoglossan were investigated. Planktotrophic larvae of E. viridis grew at 5–10 μm d−1 (shell length) at 15°C on a unicellular algal diet (the cryptophyte Rhodomonas baltica); larvae became competent one month post-hatching. Effective feeding and chloroplast acquisition typically started within 2–3 d of metamorphosis. Slugs grew about 8 mm in the first month of post-larval life. During this period, juveniles held in the light did not grow faster or survive better than conspecifics held in the dark; thus, functional kleptoplasty did not occur during first three weeks of benthic life. While larval growth rates and the nature of metamorphic cues are consistent with those of many other opisthobranch species with planktotrophic larvae, measures of post-larval growth—particularly as it pertains to kleptoplasty—is a new contribution to opisthobranch biology.

Morphology and biology of Prionospio patagonica (Annelida: Spionidae) from Chile

2006 ◽  
Vol 86 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Vasily I. Radashevsky ◽  
Mauricio Díaz ◽  
Carlos Bertrán
Keyword(s):  
Anterior Part ◽  
Small Cells ◽  
Brown Pigment ◽  
Southern Chile ◽  
Short Oesophagus ◽  
Anterior Position ◽  
Planktotrophic Larvae ◽  
Anterior Segments ◽  
The Right ◽  
Red Eyes

Prionospio patagonica inhabits temporary silty tubes intertidally and shallow subtidally in brackish water estuarine environments in southern Chile. The species is gonochoristic with the female:male ratio being close to 2:1. Females and males release gametes into water. Pelagic planktotrophic larvae were caught in the plankton in the River Valdivia estuary in October–November and in March. Development of the adult morphology is described and illustrated beginning from the 2-chaetiger larval stage. One pair of lateral eyes first appears in the early larva, and shortly after that the right median eye develops. The left median eye appears after settlement, in juveniles with 10–11 segments. Developed 6-segment larvae have three dark red eyes, short palps of equal length, no nototrochs, one pair of small cells with grasping cilia on the pygidium, a small ciliated pit, gastrotrochs on segments 2–6, long serrated bristles in notopodia, adult capillaries in noto- and neuropodia on segments 2–5, single hooks in both rami on segment 6, and one pair of provisional papillae on the pygidium. A ventral buccal bulb is present below the short oesophagus and two pairs of provisional protonephridia are present in segments 1 and 2. The wall of the anterior part of the midgut has a characteristic brown pigment. The 6-segment larvae, about 400 μm long, settle and undergo gradual metamorphosis. In adults, hooks are gradually lost from noto- and neuropodia but sabre chaetae appear from segment 7 and retain their anterior position as growth proceeds. Up to 14 pairs of cirriform branchiae develop from segment 2, and three adult cirri appear on the pygidium. The afferent and efferent arms of each branchial blood loop are interconnected by capillary loops. A greenish heart body is present in the main dorsal blood vessel in anterior segments. Up to 21 pairs of metanephridia develop in anterior sterile segments, beginning with segment 4. Transparent gonoducts are present in fertile segments.

scholarly journals Cold survival and its molecular mechanisms in a locally adapted nematode population

2021 ◽  
Author(s):  
Wenke Wang ◽  
Anna G. Flury ◽  
Jennifer L. Garrison ◽  
Rachel B. Brem
Keyword(s):  
Molecular Mechanisms ◽  
Mutational Analysis ◽  
Transcriptional Profiling ◽  
Expression Patterns ◽  
Evolutionary Model ◽  
Caenorhabditis Briggsae ◽  
Free Living ◽  
Free Living Nematode ◽  
In The Wild ◽  
Shed Light

Since Darwin, evolutionary biologists have sought to understand the drivers and mechanisms of natural trait diversity. The field advances toward this goal with the discovery of phenotypes that vary in the wild, their relationship to ecology, and their underlying genes. Here, we established resistance to extreme low temperature in the free-living nematode Caenorhabditis briggsae as an ecological and evolutionary model system. We found that C. briggsae strains of temperate origin were strikingly more cold-resistant than those isolated from tropical localities. Transcriptional profiling revealed expression patterns unique to the resistant temperate ecotype, including dozens of genes expressed at high levels even after multiple days of cold-induced physiological slowdown. Mutational analysis validated a role in cold resistance for seven such genes. As the temperate C. briggsae population likely diverged only ~700 years ago from tropical ancestors, our findings highlight a candidate case of very rapid, robust, and genetically complex adaptation, and shed light on the mechanisms at play.

EXPERIMENTAL STUDIES ON STRONGYLOIDES AGOUTII IN THE GUINEA PIG

1940 ◽  
Vol 18d (9) ◽  
pp. 307-324 ◽  
Author(s):  
Henry J. Griffiths
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Mixed Type ◽  
Experimental Studies ◽  
Prepatent Period ◽  
Acquired Immunity ◽  
Patent Period ◽  
Free Living ◽  
Mode Of Development ◽  
One Year

The suitability and tolerance of the guinea pig to infection with Strongyloides agoutii presented an opportunity for the study of the bionomics of this species in an experimental host.Serial transfer of this nematode through the guinea pig yielded a mixed type (free males and filariform larvae) of free-living development in faecal cultures which occasionally reverted to the indirect mode common to S. agoutii. A reversion to the indirect mode of development was produced when ova from faeces of guinea pigs infected with S. agoutii were cultured in sterile agouti faeces.The termination of the prepatent period of S. agoutii in the guinea pig was shown to range from 7 to 10 days, and 71% of 58 animals were positive by faecal test by the eighth day. The patent period ranged from three to eight weeks.The guinea pig was shown to develop an absolute acquired immunity to re-infection with S. agoutii. This resistance has been retained over a period of at least 6 to 13 months. An age resistance was not observed in animals one year old and over.

scholarly journals Nuclear genomic signals of the ‘microturbellarian’ roots of platyhelminth evolutionary innovation

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Christopher E Laumer ◽  
Andreas Hejnol ◽  
Gonzalo Giribet
Keyword(s):  
Nuclear Protein ◽  
Phylogenetic Signal ◽  
Evolutionary Relationships ◽  
Free Living ◽  
Evolutionary Transitions ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Evolutionary Innovation ◽  
Genomic Signals ◽  
Shed Light

Flatworms number among the most diverse invertebrate phyla and represent the most biomedically significant branch of the major bilaterian clade Spiralia, but to date, deep evolutionary relationships within this group have been studied using only a single locus (the rRNA operon), leaving the origins of many key clades unclear. In this study, using a survey of genomes and transcriptomes representing all free-living flatworm orders, we provide resolution of platyhelminth interrelationships based on hundreds of nuclear protein-coding genes, exploring phylogenetic signal through concatenation as well as recently developed consensus approaches. These analyses robustly support a modern hypothesis of flatworm phylogeny, one which emphasizes the primacy of the often-overlooked ‘microturbellarian’ groups in understanding the major evolutionary transitions within Platyhelminthes: perhaps most notably, we propose a novel scenario for the interrelationships between free-living and vertebrate-parasitic flatworms, providing new opportunities to shed light on the origins and biological consequences of parasitism in these iconic invertebrates.

Effect of intermediate host size (Cerastoderma edule) on infectivity of cercariae of Himasthla quissetensis (Echinostomatidae: Trematoda)

2005 ◽  
Vol 85 (4) ◽  
pp. 809-812 ◽  
Author(s):  
Xavier de Montaudouin ◽  
K. Thomas Jensen ◽  
Céline Desclaux ◽  
Anne M. Wegeberg ◽  
Marie C. Sajus
Keyword(s):  
Shell Length ◽  
Parasite Species ◽  
Host Size ◽  
Marine Bivalve ◽  
Free Living ◽  
Experimental Procedure ◽  
Cerastoderma Edule ◽  
Infection Pattern ◽  
South West ◽  
Fourth Species

The edible cockle (Cerastoderma edule), a common marine bivalve in semi-sheltered sandflats, is a natural host for many parasite species of the genus Himasthla (Echinostomatidae: Trematoda). In a previous paper, Wegeberg et al. (1999) showed segregation of cockle infection by three Himasthla species (H. interrupta, H. continua, H. elongata) in relation to host tissue (foot, mantle, siphon) and host size (1·5 to 14 mm shell length). Following the same experimental procedure, a fourth species, H. quissetensis, an introduced dominant parasite of cockles in Arcachon Bay (south-west France) was investigated. The infection pattern was very similar to the patterns shown by H. elongata and H. continua. Cercariae (the free-living stage shed from prosobranch snails and encysting as metacercariae in bivalves) were most successful in the shell-length range of 6–14 mm, where 74% of the added cercariae were recovered as metacercariae. The comparison with the other Himasthla species supports the previous conclusion that the efficiency of cercariae to infect cockles depends on host size.

scholarly journals Ancestral form and function of larval feeding structures are retained during development of non-planktotrophic gastropods

2020 ◽  
Vol 52 ◽  
Author(s):  
Rachel Collin ◽  
Caitlin M. Shishido ◽  
Anabell J. Cornejo ◽  
Maryna P. Lesoway
Keyword(s):  
Marine Invertebrates ◽  
The Body ◽  
Larval Feeding ◽  
Complex Structures ◽  
Video Footage ◽  
Form And Function ◽  
Body Sizes ◽  
Planktotrophic Larvae ◽  
Mode Of Development ◽  
And Function

Mode of development (MOD) is a key feature that influences the rate and direction of evolution of marine invertebrates. Although many groups include species with different MODs, the evolutionary loss of feeding larvae is thought to be irreversible as the complex structures used for larval feeding and swimming are lost, reduced, or modified in many species lacking feeding larvae. This view is largely based on observations of echinoderms. Phylogenetic analysis suggests that feeding larvae have been re-gained in at least one species of calyptraeid gastropod. Further, its sister species has retained the velum, the structure used for larval feeding and swimming. Here, we document velar morphology and function in calyptraeids with 4 different MODs. Embryos of Crepidula navicella, Crepidula atrasolea, Bostrycapulus aculeatus, Bostrycapulus odites, Bostrycapulus urraca, Crepipatella dilatata, Crepipatella occulta, Crucibulum quiriquinae and Crepidula coquimbensis all hatch as crawling juveniles, yet only Crepidula coquimbensis does not make a well-formed velum during intracapsular development. The velar dimensions of 6 species with non-planktotrophic development were similar to those of planktotrophic species, while the body sizes were significantly larger. All of the species studied were able to capture and ingest particles from suspension, but several non-planktotrophic species may ingest captured particles only occasionally. Video footage suggests that some species with adelphophagic direct development capture but frequently fail to ingest particles compared to species with the other MODs. Together these lines of evidence show that, among calyptraeids at least, species that lack planktotrophic larvae often retain the structures and functions necessary to successfully capture and ingest particles, reducing the barriers to the re-evolution of planktotrophy.

scholarly journals Transgenesis in Strongyloides and related parasitic nematodes: historical perspectives, current functional genomic applications and progress towards gene disruption and editing

Parasitology ◽  
2016 ◽  
Vol 144 (3) ◽  
pp. 327-342 ◽  
Author(s):  
J. B. LOK ◽  
H. SHAO ◽  
H. C. MASSEY ◽  
X. LI
Keyword(s):  
Developmental Regulation ◽  
Strongyloides Stercoralis ◽  
Parasitic Nematodes ◽  
Adult Males ◽  
Free Living ◽  
Historical Perspectives ◽  
Males And Females ◽  
Shed Light ◽  
Related Parasite ◽  
F1 Generation

SUMMARYTransgenesis for Strongyloides and Parastrongyloides was accomplished in 2006 and is based on techniques derived for Caenorhabditis elegans over two decades earlier. Adaptation of these techniques has been possible because Strongyloides and related parasite genera carry out at least one generation of free-living development, with adult males and females residing in soil contaminated by feces from an infected host. Transgenesis in this group of parasites is accomplished by microinjecting DNA constructs into the syncytia of the distal gonads of free-living females. In Strongyloides stercoralis, plasmid-encoded transgenes are expressed in promoter-regulated fashion in the F1 generation following gene transfer but are silenced subsequently. Stable inheritance and expression of transgenes in S. stercoralis requires their integration into the genome, and stable lines have been derived from integrants created using the piggyBac transposon system. More direct investigations of gene function involving expression of mutant transgene constructs designed to alter intracellular trafficking and developmental regulation have shed light on the function of the insulin-regulated transcription factor Ss-DAF-16. Transgenesis in Strongyloides and Parastrongyloides opens the possibility of powerful new methods for genome editing and transcriptional manipulation in this group of parasites. Proof of principle for one of these, CRISPR/Cas9, is presented in this review.

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