Dataset Information

Chloroplast incorporation and long-term photosynthetic performance through the life cycle in laboratory cultures of Elysia timida (Sacoglossa, Heterobranchia).

ABSTRACT:

Introduction

The Mediterranean sacoglossan Elysia timida is one of the few sea slug species with the ability to sequester chloroplasts from its food algae and to subsequently store them in a functional state in the digestive gland cells for more than a month, during which time the plastids retain high photosynthetic activity (= long-term retention). Adult E. timida have been described to feed on the unicellular alga Acetabularia acetabulum in their natural environment. The suitability of E. timida as a laboratory model culture system including its food source was studied.

Results

In contrast to the literature reporting that juvenile E. timida feed on Cladophora dalmatica first, and later on switch to the adult diet A. acetabulum, the juveniles in this study fed directly on A. acetabulum (young, non-calcified stalks); they did not feed on the various Cladophora spp. (collected from the sea or laboratory culture) offered. This could possibly hint to cryptic speciation with no clear morphological differences, but incipient ecological differentiation. Transmission electron microscopy of chloroplasts from A. acetabulum after initial intake by juvenile E. timida showed different states of degradation - in conglomerations or singularly - and fragments of phagosome membranes, but differed from kleptoplast images of C. dalmatica in juvenile E. timida from the literature. Based on the finding that the whole life cycle of E. timida can be completed with A. acetabulum as the sole food source, a laboratory culture system was established. An experiment with PAM-fluorometry showed that cultured E. timida are also able to store chloroplasts in long-term retention from Acetabularia peniculus, which stems from the Indo-Pacific and is not abundant in the natural environment of E. timida. Variations between three experiment groups indicated potential influences of temperature on photosynthetic capacities.

Conclusions

E. timida is a viable laboratory model system to study photosynthesis in incorporated chloroplasts (kleptoplasts). Capacities of chloroplast incorporation in E. timida were investigated in a closed laboratory culture system with two different chloroplast donors and over extended time periods about threefold longer than previously reported.

SUBMITTER: Schmitt V

PROVIDER: S-EPMC3898781 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Chloroplast incorporation and long-term photosynthetic performance through the life cycle in laboratory cultures of Elysia timida (Sacoglossa, Heterobranchia).

Schmitt Valerie V Händeler Katharina K Gunkel Susanne S Escande Marie-Line ML Menzel Diedrik D Gould Sven B SB Martin William F WF Wägele Heike H

Frontiers in zoology 20140116 1

<h4>Introduction</h4>The Mediterranean sacoglossan Elysia timida is one of the few sea slug species with the ability to sequester chloroplasts from its food algae and to subsequently store them in a functional state in the digestive gland cells for more than a month, during which time the plastids retain high photosynthetic activity (= long-term retention). Adult E. timida have been described to feed on the unicellular alga Acetabularia acetabulum in their natural environment. The suitability of ...[more]

PMID: 24428892

Similar Datasets

Project description:Despite widespread interest in solar-powered sea slugs (Sacoglossa: Gastropoda), relatively little is know about how they actually perform functional kleptoplasty. Sister-taxa Elysia timida and E. cornigera provide an ideal model system for investigating this phenomenon, since they feed on the same algal genus and only E. timida is capable of long-term kleptoplasty. Recent research has explored factors regarding functional kleptoplasty in E. timida, including their starvation longevity, digestive activity, autophagal response and photosynthetic efficiency under two different temperature conditions (18 °C and 21 °C). These studies revealed the trends E. timida displays regarding each factor during starvation as well as influences temperature has on some aspects of functional kleptoplasty. This study examines E. cornigera regarding each of these factors in an attempt to elucidate differences between each species that could explain their differing kleptoplastic abilities. Since both species naturally occur in 25 °C seawater (E. timida peak summer temperature, E. cornigera low winter temperature), each species was acclimatized to 25 °C to facilitate comparison and determine if these species exhibit physiological differences to starvation when under the same environmental conditions.When comparing the different E. timida temperature treatments, it becomes clear that increased temperatures compromise E. timida's kleptoplastic abilities. Specimens acclimatized to 25 °C revealed shorter starvation longevities surviving an average 42.4 days compared to the 95.9 day average observed in specimens exposed to 18 °C. Each temperature treatment displayed a significantly different decrease throughout the starvation period in both, the rate of photosynthetic efficiency and in the decreasing functional kleptoplast abundance. Lysosomal abundances are assessed here as indicators of different aspects of metabolic activity, which could be correlated to temperature. E. cornigera, also acclimatized to 25 °C did not display significantly similar patterns as any of the E. timida temperature treatments, having fewer incorporated kleptoplasts, a higher lysosomal response to starvation, a faster decrease in photosynthetic efficiency and a lower starvation longevity.These results confirm that each species has different physiological reactions to starvation and kleptoplast retention, even under the same conditions. While temperature affects aspects of functional kleptoplasty, it is likely not responsible for the differences in kleptoplastic abilities seen in these species.

Project description:BACKGROUND: In simultaneous hermaphrodites with copulation and internal fertilization it is often unclear whether reciprocal sperm exchange results from the unconditional willingness of both partners to donate and receive sperm, or whether it follows from a more controlled process such as conditional reciprocal sperm exchange, i.e. sperm trading. While in some sea slugs mating is assumed to be based on sperm trading, it seems to be unconditional in others. Here, we describe the unusual mating behaviour of Elysia timida, a small sacoglossan, focussing on indications for conditional reciprocity. RESULTS: E. timida shows an as yet unique combination of a long series of hypodermic transfers followed by a short phase with standard insemination into a female genital aperture. Hypodermic transfer takes place in the form of repeated small injections into the dorsal surface of the partner, interrupted by synchronised circling movements. In the final mating phase sperm is transferred into the female genital aperture in a short period. In both phases the two mating individuals show a high degree of transfer symmetry and synchrony. While total duration and number of transfers were balanced within pairs, they varied significantly between pairs. Furthermore, looking at individual hypodermic transfers within pairs, reciprocal transfers lasted longer than unilateral transfers. Final sperm transfers were always reciprocal except for two cases which also diverted from the usual pattern in ways that were suggestive of a conflict over reciprocity. CONCLUSION: Our results suggest that individual mating decisions in E. timida depend on what the partner does, indicating conditional reciprocity. If hypodermic transfers also involve the transfer of sperm (which remains to be confirmed), this system represents an up to now unique transition stage between hypodermic and standard insemination, both of which are widespread in this group of sea slugs, but never have been observed to co-occur within the same species.

Dataset Information

Chloroplast incorporation and long-term photosynthetic performance through the life cycle in laboratory cultures of Elysia timida (Sacoglossa, Heterobranchia).

Introduction

Results

Conclusions

Publications

Chloroplast incorporation and long-term photosynthetic performance through the life cycle in laboratory cultures of Elysia timida (Sacoglossa, Heterobranchia).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets