The living community inside the common periwinkle, Littorina littorea

2013 ◽  
Vol 91 (5) ◽  
pp. 293-301 ◽  
Author(s):  
John Buckland-Nicks ◽  
Sarah Ann Chisholm ◽  
Glenys Gibson
Keyword(s):  
Mantle Cavity ◽  
Snail Host ◽  
Coralline Algae ◽  
Littorina Littorea ◽  
Rocky Shores ◽  
Small Community ◽  
Wide Range ◽  
Animal Phyla ◽  
The Common ◽  
Trematode Infections

An extensive community of organisms inhabits the common periwinkle, Littorina littorea (L., 1758), along the wave-swept rocky shores of Canada’s East coast. This community, which includes both facultative and obligate endosymbionts, comprises a diverse array of species from seven animal phyla, including Annelida, Arthropoda, Gnathostomulida, Nematoda, Nemertea, and Platyhelminthes, as well as ciliates and algae. The presence of larger numbers of endosymbionts was found to correlate with specific shell characteristics of the snail host, including a wider aperture and columella, suggesting that these individuals have a larger mantle cavity relative to snails housing a small community of endosymbionts. Snails with large communities of endosymbionts were usually encrusted with coralline algae and often had trematode infections. Although L. littorea has been extensively studied since the last century, the existence of this community of organisms has passed unnoticed. The large diversity of organisms in this community suggests that these snails may provide refugia for a wide range of smaller taxa.

scholarly journals The influence of trematodes on the macroalgae consumption by the common periwinkle Littorina littorea

2008 ◽  
Vol 88 (7) ◽  
pp. 1481-1485 ◽  
Author(s):  
Karin T. Clausen ◽  
Martin H. Larsen ◽  
Nina K. Iversen ◽  
Kim N. Mouritsen
Keyword(s):  
Digestive Gland ◽  
Energy Demand ◽  
Food Source ◽  
Consumption Rate ◽  
Littorina Littorea ◽  
Infection Status ◽  
Community Regulation ◽  
Macroalgal Biomass ◽  
The Common ◽  
Trematode Infections

Trematodes are ubiquitous elements of coastal ecosystems that commonly modify the phenotype of their invertebrate hosts, often with ramifications to higher levels of ecological organization. In this context, trematode infections have been suggested to reduce the consumption of the herbivorous gastropod Littorina littorea (L.) (Mollusca: Gastropoda), in turn affecting the composition of the macroalgal community on which the snail grazes. Here, we examine the effect of two species of trematodes, Renicola roscovita and Himasthla elongata, on L. littorea's consumption in two outdoor microcosm experiments offering the snails two different ephemeral green algae species as a food source. Our results show that, irrespective of the species of parasite and food source, infection decreases consumption: uninfected snails consumed up to 65% more macroalgal biomass than infected snails. Aside from infection status, gender and size also influenced the snails' consumption rate significantly. The differing histopathological impacts of the two species of trematodes on the hosts' gonad–digestive gland complex (in which the parasites reside), suggests that parasitic castration is a likely mechanism for the reduced energy demand of infected periwinkles. Together with existing evidence, our investigation suggests that trematodes in general depress the grazing activity of L. littorea, and that the resulting community regulation occurs throughout the snails' distributional range.

Salinity Tolerances Of Some Common Prosobranchs

1972 ◽  
Vol 52 (2) ◽  
pp. 475-486 ◽  
Author(s):  
D. C. Arnold
Keyword(s):  
Atlantic Coast ◽  
Behaviour Pattern ◽  
Salinity Range ◽  
Littorina Littorea ◽  
General Interest ◽  
Rocky Shores ◽  
Ecological Studies ◽  
The Common ◽  
Considerable Range

The abundance of gastropods characteristic of rocky shores throughout the world (Southward, 1958) has encouraged investigation of their ecology and behaviour in several areas, although studies under laboratory conditions seem to have been restricted largely to the common European species Littorina littorea and Patella vulgata. Most investigations of littorinid behaviour have concentrated upon their response to light and gravity (see Newell, 1958, for a critique of earlier work), as the most important factors, after exposure, to influence life upon the shore. Variations in salinity are also significant, however, and ecological observations make it clear that littorinids are able to withstand a considerable range of salinity (Moore, 1958; Fretter & Graham, 1962; Newell, 1964; Green, 1968). But ecological studies alone do not necessarily reveal whether this capacity is to resist an adverse environment by a period of inactivity or, more particularly, to retain activity within a wide salinity range; nor do they show how far the potentialities of particular populations are related to the conditions under which they actually live. Examination of this aspect has been undertaken with L.littorea on the Atlantic coast of Canada (Gowanloch & Hayes, 1927) and with L.knysnaensis Philippi and other prosobranchs in False Bay, South Africa (Broekhuysen, 1940). However, these studies were restricted to determination of limiting salinities, without consideration of the extent to which activity occurred within the range of tolerance of the species concerned. Investigation of salinity tolerances in L.littorea is also of some general interest since, as pointed out by Newell (1958), the behaviour pattern of this species is probably fairly typical of the more mobile intertidal invertebrates.

scholarly journals Declines over the last two decades of five intertidal invertebrate species in the western North Atlantic

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Peter S. Petraitis ◽  
S. R. Dudgeon
Keyword(s):  
North Atlantic ◽  
Littorina Littorea ◽  
Rocky Shores ◽  
Nucella Lapillus ◽  
Important Food ◽  
Semibalanus Balanoides ◽  
Saturation State ◽  
Invertebrate Species ◽  
The North ◽  
The Common

Abstract Climate change has already altered the environmental conditions of the world’s oceans. Here we report declines in gastropod abundances and recruitment of mussels (Mytilus edulis) and barnacles (Semibalanus balanoides) over the last two decades that are correlated with changes in temperature and ocean conditions. Mussel recruitment is declining by 15.7% per year, barnacle recruitment by 5.0% per year, and abundances of three common gastropods are declining by an average of 3.1% per year (Testudinalia testudinalis, Littorina littorea, and Nucella lapillus). The declines in mussels and the common periwinkle (L. littorea) are correlated with warming sea temperatures and the declines in T. testudinalis and N. lapillus are correlated with aragonite saturation state, which affects rates of shell calcification. These species are common on shores throughout the North Atlantic and their loss is likely to lead to simplification of an important food web on rocky shores.

COPPER ALLOY No. 268

Alloy Digest ◽  
1976 ◽  
Vol 25 (2) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Copper Alloy ◽  
Cold Working ◽  
Heat Treating ◽  
Zinc Alloy ◽  
Good Resistance ◽  
Wide Range ◽  
Copper Zinc ◽  
The Common ◽  
Cold Worked

Abstract Copper Alloy No. 268 is a copper-zinc alloy with excellent cold-working properties and good resistance to corrosion. It can be cold worked by all the common fabrication processes and has a wide range of applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-306. Producer or source: Brass mills.

Conclusion

2018 ◽  
Author(s):  
Matthew S. Seligmann
Keyword(s):  
Corporal Punishment ◽  
Social Reform ◽  
Alcohol Intake ◽  
Religious Practice ◽  
Royal Navy ◽  
The Poor ◽  
Wide Range ◽  
The Everyday ◽  
Push Forward ◽  
The Common

As this book has shown the common conception that ‘Churchill’s “radical phase” was cast to the winds’ when he was put in charge of the Navy in October 1911, although well established in the literature, is not, in fact, accurate.1 The radical President of the Board of Trade, eager to improve the lives of the poor, became the radical Home Secretary, no less enthusiastic for social reform, who then became the radical First Lord of the Admiralty, imbued with both a desire and, perhaps more importantly, a will to intervene in order to better conditions for those who served in the Royal Navy. Accordingly, he embarked upon a major programme of improvement across a wide range of different areas all of which affected the everyday life of sailors. Alcohol intake, sexual behaviour, religious practice, corporal punishment, as well as pay and equality of progression, all came under the spotlight while Churchill was First Lord. Of course, not all of the new measures were successful and not all were progressive in the modern understanding of the term, but all of them represented significant attempts to push forward a radical agenda for change....

Punk as Folk: Continuities and Tensions in the UK and Beyond

2020 ◽  
Author(s):  
Pete Dale
Keyword(s):  
Folk Music ◽  
Music Making ◽  
Collective Creativity ◽  
Living Tradition ◽  
Wide Range ◽  
The Us ◽  
The Common ◽  
The Individual ◽  
The Uk

Numerous claims have been made by a wide range of commentators that punk is somehow “a folk music” of some kind. Doubtless there are several continuities. Indeed, both tend to encourage amateur music-making, both often have affiliations with the Left, and both emerge at least partly from a collective/anti-competitive approach to music-making. However, there are also significant tensions between punk and folk as ideas/ideals and as applied in practice. Most obviously, punk makes claims to a “year zero” creativity (despite inevitably offering re-presentation of at least some existing elements in every instance), whereas folk music is supposed to carry forward a tradition (which, thankfully, is more recognized in recent decades as a subject-to-change “living tradition” than was the case in folk’s more purist periods). Politically, meanwhile, postwar folk has tended more toward a socialist and/or Marxist orientation, both in the US and UK, whereas punk has at least rhetorically claimed to be in favor of “anarchy” (in the UK, in particular). Collective creativity and competitive tendencies also differ between the two (perceived) genre areas. Although the folk scene’s “floor singer” tradition offers a dispersal of expressive opportunity comparable in some ways to the “anyone can do it” idea that gets associated with punk, the creative expectation of the individual within the group differs between the two. Punk has some similarities to folk, then, but there are tensions, too, and these are well worth examining if one is serious about testing out the common claim, in both folk and punk, that “anyone can do it.”

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

New insights on Laminaria digitata ultrastructure through combined conventional chemical fixation and cryofixation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Christos Katsaros ◽  
Sophie Le Panse ◽  
Gillian Milne ◽  
Carl J. Carrano ◽  
Frithjof Christian Küpper
Keyword(s):  
Cell Wall ◽  
General Structure ◽  
Raw Material ◽  
Rocky Shores ◽  
Chemical Fixation ◽  
Laminaria Digitata ◽  
Vegetative Cells ◽  
Biological Studies ◽  
New Findings ◽  
Wide Range

Abstract The objective of the present study is to examine the fine structure of vegetative cells of Laminaria digitata using both chemical fixation and cryofixation. Laminaria digitata was chosen due to its importance as a model organism in a wide range of biological studies, as a keystone species on rocky shores of the North Atlantic, its use of iodide as a unique inorganic antioxidant, and its significance as a raw material for the production of alginate. Details of the fine structural features of vegetative cells are described, with particular emphasis on the differences between the two methods used, i.e. conventional chemical fixation and freeze-fixation. The general structure of the cells was similar to that already described, with minor differences between the different cell types. An intense activity of the Golgi system was found associated with the thick external cell wall, with large dictyosomes from which numerous vesicles and cisternae are released. An interesting type of cisternae was found in the cryofixed material, which was not visible with the chemical fixation. These are elongated structures, in sections appearing tubule-like, close to the external cell wall or to young internal walls. An increased number of these structures was observed near the plasmodesmata of the pit fields. They are similar to the “flat cisternae” found associated with the forming cytokinetic diaphragm of brown algae. Their possible role is discussed. The new findings of this work underline the importance of such combined studies which reveal new data not known until now using the old conventional methods. The main conclusion of the present study is that cryofixation is the method of choice for studying Laminaria cytology by transmission electron microscopy.

scholarly journals Zebrafish Models to Study New Pathways in Tauopathies

2021 ◽  
Vol 22 (9) ◽  
pp. 4626
Author(s):  
Clément Barbereau ◽  
Nicolas Cubedo ◽  
Tangui Maurice ◽  
Mireille Rossel
Keyword(s):  
Cognitive Deficits ◽  
Tau Protein ◽  
Common Point ◽  
Transgenic Models ◽  
Synaptic Loss ◽  
Wide Range ◽  
Transgenic Lines ◽  
Functional Consequences ◽  
The Common

Tauopathies represent a vast family of neurodegenerative diseases, the most well-known of which is Alzheimer’s disease. The symptoms observed in patients include cognitive deficits and locomotor problems and can lead ultimately to dementia. The common point found in all these pathologies is the accumulation in neural and/or glial cells of abnormal forms of Tau protein, leading to its aggregation and neurofibrillary tangles. Zebrafish transgenic models have been generated with different overexpression strategies of human Tau protein. These transgenic lines have made it possible to highlight Tau interacting factors or factors which may limit the neurotoxicity induced by mutations and hyperphosphorylation of the Tau protein in neurons. Several studies have tested neuroprotective pharmacological approaches. On few-days-old larvae, modulation of various signaling or degradation pathways reversed the deleterious effects of Tau mutations, mainly hTauP301L and hTauA152T. Live imaging and live tracking techniques as well as behavioral follow-up enable the analysis of the wide range of Tau-related phenotypes from synaptic loss to cognitive functional consequences.

scholarly journals Cyclotide host-defense tailored for species and environments in violets from the Canary Islands

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Blazej Slazak ◽  
Klara Kaltenböck ◽  
Karin Steffen ◽  
Martyna Rogala ◽  
Priscila Rodríguez-Rodríguez ◽  
...  
Keyword(s):  
Host Defense ◽  
Canary Islands ◽  
Cyclic Peptides ◽  
Fusarium Culmorum ◽  
Host Defense Peptides ◽  
Biological Assays ◽  
Minimal Inhibitory Concentrations ◽  
Wide Range ◽  
The Common ◽  
Teide Volcano

AbstractCyclotides are cyclic peptides produced by plants. Due to their insecticidal properties, they are thought to be involved in host defense. Violets produce complex mixtures of cyclotides, that are characteristic for each species and variable in different environments. Herein, we utilized mass spectrometry (LC–MS, MALDI-MS), transcriptomics and biological assays to investigate the diversity, differences in cyclotide expression based on species and different environment, and antimicrobial activity of cyclotides found in violets from the Canary Islands. A wide range of different habitats can be found on these islands, from subtropical forests to dry volcano peaks at high altitudes. The islands are inhabited by the endemic Viola palmensis, V. cheiranthifolia, V. anagae and the common V. odorata. The number of cyclotides produced by a given species varied in plants from different environments. The highest diversity was noted in V. anagae which resides in subtropical forest and the lowest in V. cheiranthifolia from the Teide volcano. Transcriptome sequencing and LC–MS were used to identify 23 cyclotide sequences from V. anagae. Cyclotide extracts exhibited antifungal activities with the lowest minimal inhibitory concentrations noted for V. anagae (15.62 μg/ml against Fusarium culmorum). The analysis of the relative abundance of 30 selected cyclotides revealed patterns characteristic to both species and populations, which can be the result of genetic variability or environmental conditions in different habitats. The current study exemplifies how plants tailor their host defense peptides for various habitats, and the usefulness of cyclotides as markers for chemosystematics.

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