The perfection of sponges.

Bidder, G P

doi:10.1111/j.1095-8312.1937.tb00131.x

Cited by 15 publications

(6 citation statements)

References 15 publications

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“…The calcareous sponge porocyte forms distinct junctions with cells of each layer. Our experiments confirm that, like the demosponge porocyte, the tubular calcareous sponge porocyte contracts in response to strong mechanical agitation (Haeckel 1872; Bidder 1937; Jones 1966) and also when left in stagnant water. Use of chemical anesthetics also caused the ostia to close.…”

Section: Discussionsupporting

confidence: 76%

“…5H), suggesting that these features of collars are not artifacts. Bidder (1892) proposed that collars contract as the cell elongates when sated but, in the specimens we observed, many short choanocytes also had negligible collars.…”

Section: Porocytes and Choanocytesmentioning

confidence: 59%

“…But their overall morphology appears to be variable. From the earliest descriptions of calcareous sponges, authors have noted the unusual length of the apical region of choanocytes, referring to it as the rostrum (Carter 1871), neck (Haeckel 1872Schulze 1875), and column (Bidder 1892;Duboscq & Tuzet 1939) (Fig. 9).…”

Section: Porocytes and Choanocytesmentioning

confidence: 99%

“…9). Bidder (1892) initially proposed that the length of the choanocyte reflected feeding state: a fully fed choanocyte becomes narrow and tall, the basal part detaches and moves into the mesohyl and joins the pinacoderm to excrete waste, while the apical portion resumes normal feeding. Bidder also suggested that the choanocytes extend their neck region in conditions of anoxia.…”

Section: Porocytes and Choanocytesmentioning

confidence: 99%

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Ultrastructure and embryonic development of a syconoid calcareous sponge

Eerkes-Medrano

Leys

2006

Invertebrate Biology

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Abstract. Recent molecular data suggest that the Porifera is paraphyletic (Calcarea1Silicea) and that the Calcarea is more closely related to the Metazoa than to other sponge groups, thereby implying that a sponge-like animal gave rise to other metazoans. One ramification of these data is that calcareous sponges could provide clues as to what features are shared among this ancestral metazoan and higher animals. Recent studies describing detailed morphology in the Calcarea are lacking. We have used a combination of microscopy techniques to study the fine structure of Sycon coactum URBAN 1905, a cosmopolitan calcareous sponge. The sponge has a distinct polarity, consisting of a single tube with an apically opening osculum. Finger-like chambers, several hundred micrometers in length, form the sides of the tube. The inner and outer layers of the chamber wall are formed by epithelia characterized by apical-basal polarity and occluding junctions between cells. The outer layer-the pinacoderm-and atrial cavity are lined by plate-like cells (pinacocytes), and the inner choanoderm is lined by a continuous sheet of choanocytes. Incurrent openings of the sponge are formed by porocytes, tubular cells that join the pinacoderm to the choanoderm. Between these two layers lies a collagenous mesohyl that houses sclerocytes, spicules, amoeboid cells, and a progression of embryonic stages. The morphology of choanocytes and porocytes is plastic. Ostia were closed in sponges that were vigorously shaken and in sponges left in still water for over 30 min. Choanocytes, and in particular collar microvilli, varied in size and shape, depending on their location in the choanocyte chamber. Although some of the odd shapes of choanocytes and their collars can be explained by the development of large embryos first beneath and later on top of the choanocytes, the presence of many fused collar microvilli on choanocytes may reflect peculiarities of the hydrodynamics in large syconoid choanocyte chambers. The unusual formation of a hollow blastula larva and its inversion through the choanocyte epithelium are suggestive of epithelial rather than mesenchymal cell movements. These details illustrate that calcareous sponges have characteristics that allow comparison with other metazoans-one of the reasons they have long been the focus of studies of evolution and development.

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Section: Discussionsupporting

confidence: 76%

Section: Porocytes and Choanocytesmentioning

confidence: 59%

Section: Porocytes and Choanocytesmentioning

confidence: 99%

Section: Porocytes and Choanocytesmentioning

confidence: 99%

See 2 more Smart Citations

Ultrastructure and embryonic development of a syconoid calcareous sponge

Eerkes-Medrano

Leys

2006

Invertebrate Biology

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“…The second hypothesis holds that epidermal contraction originates in pinacocytes and is mainly based on observations of living and fixed material (Minchin 1900; Parker 1910; Wilson 1910; Bidder 1937; Jones 1957). The hypothesis is supported by the presence of actin filaments (Bagby 1970; Matsuno et al 1988).…”

Section: What Is the Non‐muscular Contractile Effector?mentioning

confidence: 99%

Evolutionary emergence of synaptic nervous systems: what can we learn from the non‐synaptic, nerveless Porifera?

Nickel

2010

Invertebrate Biology

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Abstract. The Porifera represent one of the only two recent nerveless and muscleless metazoan phyla. Nevertheless, sponges provide behavioral, physiological, pharmacological, morphological, and, more recently, an increasing amount of genetic evidence for a paracrine pre‐nervous integration system. Although this system might be derived, it allows us to draw conclusions, on the basis of comparative data, about the origin of the nervous system sensu stricto as found in the eumetazoan phyla. The goal of the present review is to compile recent evidence on the sponge integration systems. Based on this framework, new light is also shed on the evolutionary origin of the eumetazoan synaptic nervous systems, which can be regarded to form an evolutionary biochemical continuum with the paracrine signaling system in sponges. Thus, we can assume that the evolutionary transition from a paracrine‐dominated, pre‐nervous system to an electrochemically dominated, primordial nervous system resulted in part from compartmentalization effects. As intermediate evolutionary stages, regionalized synapse precursor areas might have occurred within pre‐nervous cells, which foreshadowed the highly organized synaptic scaffolds present in recent nerve cells of the Eumetazoa.

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Osmoregulation in the fresh water sponge, Spongilla lacustris

Brauer

1975

J. Exp. Zool.

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External medium passed through the canal system of small Spongilla lacustris at the rate of 70 body volumes per hour, allowing for little or no modification of its composition by the animal. Consequently any osmotic gradient between medium and animal was experienced at the cell level. Forty or more contractile vacuoles arranged around the nucleus in each basal pinacocyte removed fluid at the rate of 24.7 k 1.0 ym3lcelUrnin in 1 . 3 milliosmolal (mosm) medium, Output of the contractile vacuoles depended in a nearly linear fashion on the osmotic concentration of the medium, decreasing to zero at 12-16 mosm. The contractile vacuoles responded to the osmotic concentration of the medium, not to ionic strength or the concentration ratios of particular ions. Osmotic concentration of the vacuolar fluid can be estimated as 10-40 mosm, leading to the hypothesis that contractile vacuoles of sponges function by isotonic water separation.

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The perfection of sponges.

Cited by 15 publications

References 15 publications

Ultrastructure and embryonic development of a syconoid calcareous sponge

Ultrastructure and embryonic development of a syconoid calcareous sponge

Evolutionary emergence of synaptic nervous systems: what can we learn from the non‐synaptic, nerveless Porifera?

Osmoregulation in the fresh water sponge, Spongilla lacustris

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