scholarly journals Phenotypic plasticity revealed by molecular studies on reef corals of Fungia (Cycloseris) spp. (Scleractinia: Fungiidae) near river outlets

2006 ◽  
Vol 75 (03-04) ◽  
pp. 195-201 ◽  
Author(s):  
Adriaan Gittenberger ◽  
Bert W. Hoeksema
Keyword(s):  
Phenotypic Plasticity ◽  
Sea Water ◽  
Patch Reef ◽  
Mutual Distance ◽  
Allozyme Electrophoresis ◽  
Reef Corals ◽  
Close Proximity ◽  
Molecular Studies ◽  
Mushroom Coral ◽  
Field Area

On a patch reef off Makassar, Sulawesi, Indonesia, corals identified as Fungia (Cycloseris) costulata, Fungia (Cycloseris) tenuis and Fungia (Cycloseris) cf costulata were collected down to a maximum depth of 10 m. The corals lived sympatrically. Mushroom coral clones resulting from fragmentation can be recognized by their equal coloration and close proximity. Therefore, to ensure that no clones were collected, corals of dissimilar colors were selected at a mutual distance of 5 m. The corals were kept alive in two 30 liter sea-water aquariums with an air-pump. They were photographed in detail. Using allozyme electrophoresis in a laboratory close to the field area, it was tested whether the separate coral morphs should be considered three species. Eventually it was concluded that there are only two species, i.e. F. (C.) costulata and F. (C.) tenuis, of which F. (C.) costulata has two distinct morphs, one of which may be an eco-phenotype occurring on reefs off river outlets or inside estuaries.

scholarly journals The mushroom coral as a habitat

2011 ◽  
Vol 92 (4) ◽  
pp. 647-663 ◽  
Author(s):  
Bert W. Hoeksema ◽  
Sancia E.T. Van der Meij ◽  
Charles H.J.M. Fransen
Keyword(s):  
Coral Species ◽  
Marine Biodiversity ◽  
Coral Host ◽  
Associated Fauna ◽  
Reef Corals ◽  
Symbiotic Relationships ◽  
Mushroom Coral ◽  
Endosymbiotic Algae ◽  
Associated Species ◽  
Shallow Seas

The evolution of symbiotic relationships involving reef corals has had much impact on tropical marine biodiversity. Because of their endosymbiotic algae (zooxanthellae) corals can grow fast in tropical shallow seas where they form reefs that supply food, substrate and shelter for other organisms. Many coral symbionts are host-specific, depending on particular coral species for their existence. Some of these animals have become popular objects for underwater photographers and aquarists, whereas others are hardly noticed or considered pests. Loss of a single coral host species also leads to the disappearance of some of its associated fauna. In the present study we show which mushroom corals (Scleractinia: Fungiidae) are known to act as hosts for other organisms, such as acoel flatworms, copepods, barnacles, gall crabs, pontoniine shrimps, mytilid bivalves, epitoniid snails, coralliophilid snails, fish and certain types of zooxanthellae. Several of these associated organisms appear to be host-specific whereas other species are generalists and not even necessarily restricted to fungiid hosts.Heliofungia actiniformisis one of the most hospitable coral species known with a recorded associated fauna consisting of at least 23 species. The availability of a phylogeny reconstruction of the Fungiidae enables comparisons of closely related species of mushroom corals regarding their associated fauna. Application of a phylogenetic ecological analysis indicates that the presence or absence of associated organisms is evolutionarily derived or habitat-induced. Some associations appear to be restricted to certain evolutionary lineages within the Fungiidae, whereas the absence of associated species may be determined by ecomorphological traits of the host corals, such as coral dimensions (coral diameter and thickness) and polyp shape (tentacle size).

Evaluating a pattern of ecological character displacement: charr jaw morphology and diet diverge in sympatry versus allopatry across catchments in Hokkaido, Japan

2019 ◽  
Vol 129 (2) ◽  
pp. 356-378 ◽  
Author(s):  
Shigeru Nakano ◽  
Kurt D Fausch ◽  
Itsuro Koizumi ◽  
Yoichiro Kanno ◽  
Yoshinori Taniguchi ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Character Displacement ◽  
Invertebrate Drift ◽  
Similar Species ◽  
Dolly Varden ◽  
Terrestrial Invertebrates ◽  
Rapid Responses ◽  
Close Proximity ◽  
Foraging Modes ◽  
Significant Divergence

Abstract Similar species that overlap in sympatry may diverge in characters related to resource use as a result of evolution or phenotypic plasticity. Dolly Varden charr (Salvelinus malma) and whitespotted charr (S. leucomaenis) overlap along streams in Hokkaido, Japan, and compete by interference for invertebrate drift-foraging positions. Previous research has shown that as drift declines during summer, Dolly Varden shift foraging modes to capture benthic prey, a behaviour facilitated by their subterminal jaw morphology. We compare body and jaw morphology of Dolly Varden in sympatry vs. allopatry in two locations to test for character displacement. Statistical analysis showed significant divergence in characters related to foraging, which was correlated with variation in individual charr diets. Dolly Varden in sympatry had shorter heads and lower jaws than in allopatry, and even within sites charr with these characteristics fed less on drifting terrestrial invertebrates but more on benthic aquatic invertebrates. Those in allopatry had longer heads and lower jaws, and fed more on terrestrial invertebrates. The close proximity of sites in one stream suggests that Dolly Varden may display phenotypic plasticity similar to other charr, allowing rapid responses in morphology to the presence of competitors. These morphological shifts probably help them maintain positive fitness when competing with whitespotted charr in Hokkaido streams.

scholarly journals Impact of salinity on element incorporation in two benthic foraminiferal species with contrasting magnesium contents

2018 ◽  
Vol 15 (7) ◽  
pp. 2205-2218 ◽  
Author(s):  
Esmee Geerken ◽  
Lennart Jan de Nooijer ◽  
Inge van Dijk ◽  
Gert-Jan Reichart
Keyword(s):  
Ocean Circulation ◽  
Sea Water ◽  
Hydrological Cycle ◽  
Field Studies ◽  
Salinity Range ◽  
Controlled Growth ◽  
Foraminiferal Species ◽  
Seawater Salinity ◽  
Close Proximity ◽  
Mg Content

Abstract. Accurate reconstructions of seawater salinity could provide valuable constraints for studying past ocean circulation, the hydrological cycle and sea level change. Controlled growth experiments and field studies have shown the potential of foraminiferal Na ∕ Ca as a direct salinity proxy. Incorporation of minor and trace elements in foraminiferal shell carbonate varies, however, greatly between species and hence extrapolating calibrations to other species needs validation by additional (culturing) studies. Salinity is also known to impact other foraminiferal carbonate-based proxies, such as Mg ∕ Ca for temperature and Sr ∕ Ca for sea water carbonate chemistry. Better constraints on the role of salinity on these proxies will therefore improve their reliability. Using a controlled growth experiment spanning a salinity range of 20 units and analysis of element composition on single chambers using laser ablation-Q-ICP-MS, we show here that Na ∕ Ca correlates positively with salinity in two benthic foraminiferal species (Ammonia tepida and Amphistegina lessonii). The Na ∕ Ca values differ between the two species, with an approximately 2-fold higher Na ∕ Ca in A. lessonii than in A. tepida, coinciding with an offset in their Mg content (∼ 35 mmol mol−2 versus ∼ 2.5 mmol mol−1 for A. lessonii and A. tepida, respectively). Despite the offset in average Na ∕ Ca values, the slopes of the Na ∕ Ca–salinity regressions are similar between these two species (0.077 versus 0.064 mmol mol−1 change per salinity unit). In addition, Mg ∕ Ca and Sr ∕ Ca are positively correlated with salinity in cultured A. tepida but show no correlation with salinity for A. lessonii. Electron microprobe mapping of incorporated Na and Mg of the cultured specimens shows that within chamber walls of A. lessonii, Na ∕ Ca and Mg ∕ Ca occur in elevated bands in close proximity to the primary organic lining. Between species, Mg banding is relatively similar, even though Mg content is 10 times lower and that variation within the chamber wall is much less pronounced in A. tepida. In addition, Na banding is much less prominent in this species than it is in A. lessonii. Inter-species differences in element banding reported here are hypothesized to be caused by differences in biomineralization controls responsible for element uptake.

Morphological and molecular studies of Neosynechococcus sphagnicola, gen. et sp. nov. (Cyanobacteria, Synechococcales)

Phytotaxa ◽  
2014 ◽  
Vol 170 (1) ◽  
pp. 024 ◽  
Author(s):  
PETR DVOŘÁK ◽  
FRANTIŠEK HINDÁK ◽  
PETR HAŠLER ◽  
ALICA HINDÁKOVÁ ◽  
ALOISIE POULÍČKOVÁ
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
New Genus ◽  
Peat Bog ◽  
Rrna Gene ◽  
Filamentous Cyanobacteria ◽  
Ecological Features ◽  
Close Proximity ◽  
Molecular Studies ◽  
The 16S Rrna Gene

The genus Synechococcus represents an enigmatic group of cyanobacteria with very simple unicellular morphology and polyphyletic evolutionary origin. Here, we describe a new genus based on strain of Synechococcus-like cyanobacterium. The strain was isolated from the peat bog Klin (Slovakia), where it occupies different niches such as hyaline cells of Sphagnum, sheaths of cyanobacteria, dead cells of desmids, carapaces of dead crustaceans, and solitary in detritus. We describe this new genus using a combination of molecular, morphological and ecological features. A phylogeny of the 16S rRNA gene, 16S-23S ITS and rbcL loci showed a separate position of the investigated strain and its close proximity to filamentous cyanobacteria. Therefore, it is a novel lineage of Synechococcus-like cyanobacteria illustrating the polyphyletic nature of the genus Synechococcus. Moreover, the strain exhibits unique morphological and ecological features, which allow us to erect the new monospecific genus Neosynechococcus.

Stromatoporoids from the Famennian (Devonian) Wabamun Formation, Normandville oilfield, north–central Alberta, Canada

1988 ◽  
Vol 62 (03) ◽  
pp. 411-419 ◽  
Author(s):  
Colin W. Stearn
Keyword(s):  
Patch Reef ◽  
Abundant Species ◽  
The Other ◽  
North Central ◽  
Biotic Crisis

Stromatoporoids are the principal framebuilding organisms in the patch reef that is part of the reservoir of the Normandville field. The reef is 10 m thick and 1.5 km2in area and demonstrates that stromatoporoids retained their ability to build reefal edifices into Famennian time despite the biotic crisis at the close of Frasnian time. The fauna is dominated by labechiids but includes three non-labechiid species. The most abundant species isStylostroma sinense(Dong) butLabechia palliseriStearn is also common. Both these species are highly variable and are described in terms of multiple phases that occur in a single skeleton. The other species described areClathrostromacf.C. jukkenseYavorsky,Gerronostromasp. (a columnar species), andStromatoporasp. The fauna belongs in Famennian/Strunian assemblage 2 as defined by Stearn et al. (1988).

Effects of Vincristine on Endothelial Microtubules in the Spinal Cord

1976 ◽  
Vol 34 ◽  
pp. 58-59
Author(s):  
John L. Beggs ◽  
John D. Waggener ◽  
Wanda Miller
Keyword(s):  
Spinal Cord ◽  
Biological Activity ◽  
Horseradish Peroxidase ◽  
Transport Mechanism ◽  
Vasogenic Edema ◽  
Vesicular Transport ◽  
Close Proximity

Microtubules (MT) are versatile organelles participating in a wide variety of biological activity. MT involvement in the movement and transport of cytoplasmic components has been well documented. In the course of our study on trauma-induced vasogenic edema in the spinal cord we have concluded that endothelial vesicles contribute to the edema process. Using horseradish peroxidase as a vascular tracer, labeled endothelial vesicles were present in all situations expected if a vesicular transport mechanism was in operation. Frequently,labeled vesicles coalesced to form channels that appeared to traverse the endothelium. The presence of MT in close proximity to labeled vesicles sugg ested that MT may play a role in vesicular activity.

Experiments with a scanning tunneling microscope (STM) mounted in a scanning electron microscope (SEM)

1986 ◽  
Vol 44 ◽  
pp. 636-639
Author(s):  
Oliver C. Wells ◽  
Mark E. Welland
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Mechanical Stability ◽  
Tunneling Current ◽  
Feedback System ◽  
Scanning Tunneling ◽  
Surface Profiling ◽  
Close Proximity ◽  
Metal Tip ◽  
Scanning Electron

Scanning tunneling microscopes (STM) exist in two versions. In both of these, a pointed metal tip is scanned in close proximity to the specimen surface by means of three piezos. The distance of the tip from the sample is controlled by a feedback system to give a constant tunneling current between the tip and the sample. In the low-end STM, the system has a mechanical stability and a noise level to give a vertical resolution of between 0.1 nm and 1.0 nm. The atomic resolution STM can show individual atoms on the surface of the specimen.A low-end STM has been put into the specimen chamber of a scanning electron microscope (SEM). The first objective was to investigate technological problems such as surface profiling. The second objective was for exploratory studies. This second objective has already been achieved by showing that the STM can be used to study trapping sites in SiO2.

Ultrastructure and Senescence in an Achloroplastic Mutant of Hordeum vulgare L. cv. Dyan

1992 ◽  
Vol 50 (1) ◽  
pp. 844-845
Author(s):  
R.H.M. Cross ◽  
C.E.J. Botha ◽  
A.K. Cowan ◽  
B.J. Hartley
Keyword(s):  
Cell Wall ◽  
Hordeum Vulgare ◽  
Leaf Tissue ◽  
Ultrastructural Changes ◽  
Hordeum Vulgare L ◽  
Mesophyll Cells ◽  
Lethal Mutant ◽  
Cytoplasmic Matrix ◽  
Close Proximity ◽  
Pinocytotic Vesicles

Senescence is an ordered degenerative process leading to death of individual cells, organs and organisms. The detection of a conditional lethal mutant (achloroplastic) of Hordeum vulgare has enabled us to investigate ultrastructural changes occurring in leaf tissue during foliar senescence.Examination of the tonoplast structure in six and 14 day-old mutant tissue revealed a progressive degeneration and disappearance of the membrane, apparently starting by day six in the vicinity of the mitochondria associated with the degenerating proplastid (Fig. 1.) where neither of the plastid membrane leaflets is evident (arrows, Fig. 1.). At this stage there was evidence that the mitochondrial membranes were undergoing retrogressive changes, coupled with disorganization of cristae (Fig. 2.). Proplastids (P) lack definitive prolamellar bodies. The cytoplasmic matrix is largely agranular, with few endoplasmic reticulum (ER) cisternae or polyribosomal aggregates. Interestingly, large numbers of actively-budding dictysomes, associated with pinocytotic vesicles, were observed in close proximity to the plasmalemma of mesophyll cells (Fig. 3.). By day 14 however, mesophyll cells showed almost complete breakdown of subcellular organelle structure (Fig. 4.), and further evidence for the breakdown of the tonoplast. The final stage of senescence is characterized by the solubilization of the cell wall due to expression and activity of polygalacturonase and/or cellulose. The presence of dictyosomes with associated pinocytotic vesicles formed from the mature face, in close proximity to both the plasmalemma and the cell wall, would appear to support the model proposed by Christopherson for the secretion of cellulase. This pathway of synthesis is typical for secretory glycoproteins.

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