Identification of novel yolk ferritins unique to planarians: planarians supply aluminum rather than iron to vitellaria in egg capsules

2021 ◽  
Author(s):  
Osamu Kawase ◽  
Hisashi Iwaya ◽  
Yoshiya Asano ◽  
Hiromoto Inoue ◽  
Seiya Kudo ◽  
...  
Keyword(s):  
Egg Capsules

Reproductive Failure in Populations of the Dog-Whelk, Nucella Lapillus, Caused by Imposex Induced by Tributyltin from Antifouling Paints

1986 ◽  
Vol 66 (4) ◽  
pp. 767-777 ◽  
Author(s):  
P. E. Gibbs ◽  
G. W. Bryan
Keyword(s):  
Vas Deferens ◽  
Early Stage ◽  
Premature Death ◽  
Intermediate Stage ◽  
Reproductive Failure ◽  
Nucella Lapillus ◽  
Egg Capsules ◽  
Male Characters ◽  
High Incidence ◽  
Declining Populations

The development of male characters, notably a penis and a vas deferens, on the female (the phenomenon of ‘imposex’) of the dog-whelk, Nucella lapillus, is described. Three stages are recognized: an ‘early’ stage involving the formation of a vas deferens and a small penis, an ‘intermediate’ stage characterized by the enlargement of the female penis to a size approaching that of the male and a ‘late’ stage during which the female opening (vulva) is occluded by overgrowth of vas deferens tissue. This blockage of the pallial oviduct prevents the release of egg capsules and renders the female sterile. The extent and cause of such reproductive failure is evident from the high incidence of females containing aborted capsules in declining populations close to sources of tributyltin (TBT) contamination. These same populations comprise fewer females than expected and it would appear that the accumulation of aborted capsules within the pallial oviduct eventually causes the premature death of the female.

scholarly journals Activity of the nematophagous fungi Pochonia chlamydosporia, Duddingtonia flagrans and Monacrosporium thaumasium on egg capsules of Dipylidium caninum

2009 ◽  
Vol 166 (1-2) ◽  
pp. 86-89 ◽  
Author(s):  
Juliana Milani Araujo ◽  
Jackson Victor de Araújo ◽  
Fabio Ribeiro Braga ◽  
Rogério Oliva Carvalho ◽  
Sebastião Rodrigo Ferreira
Keyword(s):  
Nematophagous Fungi ◽  
Duddingtonia Flagrans ◽  
Pochonia Chlamydosporia ◽  
Egg Capsules ◽  
Dipylidium Caninum

The encapsular developmental sequence of the mesogastropod Turritella communis (Gastropoda: Turritellidae)

1992 ◽  
Vol 72 (4) ◽  
pp. 783-805 ◽  
Author(s):  
J. J. Kennedy ◽  
B. F. Keegan
Keyword(s):  
Germinal Vesicle ◽  
Average Diameter ◽  
Meiotic Maturation ◽  
Developmental Sequence ◽  
Early Cleavage ◽  
Mantle Tissue ◽  
Cell Stage ◽  
Egg Capsules ◽  
Eupyrene Sperm ◽  
The Right

The development of the lecithotrophic encapsulated larva of the internally-fertilizing, sublittoral gastropod Turritella communis Risso 1826 was documented using scanning electron microscopy and light microscopy. Encapsulated development was completed in 12 days at 15°C in the laboratory. Spawning occurred above ~10°C. Spawn masses consisted of numerous gelatinous egg capsules, each of which contained ~28 eggs, encased in albumen and fertilizing sperm. The eggs had an average diameter of 139 μm. Fertilization was accomplished by unpaired eupyrene sperm and occurred at the germinal vesicle stage. The developmental sequence followed the typical gastropod pattern, but was unique in a number of respects. Polar lobes were produced during meiotic maturation and early cleavage, with an especially large lobe occurring in association with the first cleavage, which was unequal. The blastula developed into a dorso-ventrally flattened placula at the 70-cell stage. Gastrulation occurred through invagination and epiboly acting together, and was uniquely accompanied by the development of ectodermal microvilli measuring ~ 1 μm in length. Extra-embryonic albumen began to be depleted after the development of the microvilli. It is proposed that the ciliated telotrochal cells gave rise to the pair of statocysts. Torsion was additionally observed to be facilitated by the growth of pre-mantle tissue on the right side and retardation of growth on the left side.

scholarly journals Reproductive biology of Sympterygia bonapartii (Chondrichthyes: Rajiformes: Arhynchobatidae) in San Matías Gulf, Patagonia, Argentina

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
María L. Estalles ◽  
María R. Perier ◽  
Edgardo E. Di Giácomo
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Biology ◽  
Early Spring ◽  
Egg Laying ◽  
Reproductive Pattern ◽  
Reproductive Parameters ◽  
Egg Capsules ◽  
Northern Patagonia ◽  
Total Length

ABSTRACT This study estimates and analyses the reproductive parameters and cycle of Sympterygia bonapartii in San Matías Gulf, northern Patagonia, Argentina. A total of 827 males and 1,299 females were analysed. Males ranged from 185 to 687 mm of total length (TL) and females from 180 to 742 mm TL. Sexual dimorphism was detected; females were larger, heavier, exhibited heavier livers, wider discs and matured at lager sizes than males. Immature females ranged from 180 to 625 mm TL, maturing females from 408 to 720 mm TL, mature ones from 514 to 742 mm TL and females with egg capsules from 580 to 730 mm TL. Immature males ranged from 185 to 545 mm TL, maturing ones from 410 to 620 mm TL and mature males from 505 to 687 mm TL. Size at which 50% of the skates reached maturity was estimated to be 545 mm TL for males and 594 mm TL for females. According to the reproductive indexes analysed, S. bonapartii exhibited a seasonal reproductive pattern. Mating may occur during winter-early spring and the egg-laying season, during spring and summer.

Newly discovered parasitic Turbellaria of opisthobranch gastropods

2010 ◽  
Vol 91 (5) ◽  
pp. 1123-1133 ◽  
Author(s):  
Kosuke Sudo ◽  
Yoshiaki J. Hirano ◽  
Yayoi M. Hirano
Keyword(s):  
Life History ◽  
Obligate Parasite ◽  
Egg Capsules ◽  
Parasitic Worm ◽  
The Family

An endoparasitic platyhelminth from six species of sacoglossan opisthobranchs was collected at several localities of temperate to subtropical waters in Japan. Poecilostomatoid copepods (all species of Splanchnotrophidae and several species of Philoblennidae) and a few digenean flukes had been the only endoparasitic metazoans known for opisthobranch hosts. The newly discovered parasite was 1 to 15 mm in length and had no eyes, mouth, pharynx, or intestine. It had no external organs for parasitic life (e.g. attachment organs) and inhabited the haemocoel of the host. When mature, it emerged from the host and secreted a silky substance around itself to form a cocoon. The cocoon contained egg capsules with 19–42 eggs. Larvae, hatched from the capsule, had a ciliated body and a pair of eye spots. They were negatively phototactic and capable of invading suitable hosts. These morphological and life history features suggest this parasitic worm may belong to the family Fecampiidae (Platyhelminthes: Turbellaria), one of a few obligate parasite taxa in Turbellaria. Molluscan hosts which are common for parasitic Platyhelminthes have not previously been known for this family. The newly discovered parasite may be important for understanding the evolution of parasitism in Platyhelminthes.

Hierarchical Assembly of Tough Bioelastomeric Egg Capsules is Mediated by a Bundling Protein

2017 ◽  
Vol 18 (3) ◽  
pp. 931-942 ◽  
Author(s):  
Jun Jie Loke ◽  
Akshita Kumar ◽  
Shawn Hoon ◽  
Chandra Verma ◽  
Ali Miserez
Keyword(s):  
Hierarchical Assembly ◽  
Egg Capsules

The reproductive cycle and size at maturity observed in Cancer pagurus in the Shetland Islands, Scotland

2007 ◽  
Vol 87 (5) ◽  
pp. 1181-1189 ◽  
Author(s):  
Shelly M.L. Tallack
Keyword(s):  
Reproductive Cycle ◽  
Carapace Width ◽  
Biological Indicators ◽  
Size At Maturity ◽  
Mating Period ◽  
Spawning Period ◽  
Functional Maturity ◽  
Shetland Islands ◽  
Egg Capsules ◽  
Cancer Pagurus

Seasonality of the reproductive cycle for Cancer pagurus was determined using three biological indicators: extruding sperm plugs (mating period), extrusion of eggs (spawning period) and presence of empty egg capsules (hatching period). Sperm plugs were found only in recently moulted females, indicating that mating coincides with moulting periods. Cancer pagurus mating indicators were observed during the summer months and into autumn; spawning occurred in winter, and broods were hatching throughout the summer into early autumn. Size at maturity, was assessed using a variety of reproductive and morphometric criteria; estimates from reproductive criteria are generally larger than those from morphometric criteria and these differences are often indicative of ‘functional’ vs ‘behavioural’ maturity. In C. pagurus, size at maturity estimates ranged from 101.6–125.0 mm carapace width (CW) in males and 110.7–147.3 mm CW in females; the sizes at functional maturity proposed are larger than those from morphometric indicators.

scholarly journals Microscopic structure of the egg capsule of Atlantoraja cyclophora (Elasmobranchii: Rajidae: Arhynchobatinae)

2005 ◽  
Vol 5 (2) ◽  
pp. 305-308 ◽  
Author(s):  
María Cristina Oddone
Keyword(s):  
South America ◽  
Transverse Section ◽  
Microscopic Structure ◽  
Capsule Wall ◽  
Atlantic Region ◽  
Egg Capsules ◽  
Naked Eye ◽  
Egg Case ◽  
Egg Capsule

The microscopic structure of the egg capsules of Atlantoraja cyclophora, a species endemic to the Atlantic region of South America, is presented in this paper. In a transverse section, the dorsal face of the egg case is 70mu in width, and is subdivided into four layers. Ventrally, the egg capsule wall is 60 mu wide and composed of three layers. Both faces are covered by prickles which render the egg capsule surface striated to the naked eye.

scholarly journals Mexican dancer in Ecuador: molecular confirmation, embryology and planktotrophy in the sea slug Elysia diomedea

2020 ◽  
Vol 52 ◽  
Author(s):  
Lola Moreano-Arrobo ◽  
Oscar D. Pérez ◽  
Federico D. Brown ◽  
Fernanda X. Oyarzún ◽  
Cristian B. Canales-Aguirre
Keyword(s):  
Genetic Information ◽  
Ex Situ ◽  
Adult Size ◽  
Mtdna Sequences ◽  
Cell Stage ◽  
Egg Capsules ◽  
Northeast Pacific ◽  
Morphological Differences ◽  
General Aspects ◽  
Veliger Larvae

Elysia diomedea varies in adult size and color across its geographical distribution in Ecuador. Because of morphological variation and the absence of genetic information for this species in Ecuador, we analyzed mtDNA sequences in three populations (Ballenita, La Cabuya, and Mompiche) and confirmed that (1) individuals from the three locations belonged to E. diomedea and (2) that there was no population structure that could explain their morphological differences. Next, we analyzed general aspects about the reproductive biology and embryology of this species. Live slugs from the Ballenita population were maintained and reproduced ex situ. Egg ribbons and embryos were fixed and observed by brightfield and confocal microscopy. We observed a single embryo per capsule, 98 embryos per mm2 of egg ribbon, and compared the cleavage pattern of this species to other heterobranchs and spiralians. E. diomedea early development was characterized by a slight unequal first cleavage, occurrence of a 3-cell stage in the second cleavage, and the formation of an enlarged second quartet of micromeres. We observed clear yolk bodies in the egg capsules of some eggs ribbons at early stages of development. Both reproductive and embryological characteristics, such as presence of stomodeum in the larva, and ingestion of particles after hatching confirmed the planktotrophic veliger larvae of this species, consistent with the majority of sacoglossans from the Eastern and Northeast Pacific Oceans.

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