Histological and ultrastructural study of the stomach of the air-breathing Ancistrus multispinnis (Siluriformes, Teleostei)

Histological and ultrastructural analyses of selected segments of the digestive tract of the fish Ancistrus multispinnis were done, particular attention being paid to the cytological barrier between blood and air. Three regions can be distinguished in the stomach of A. multispinnis: cardia, corpus, and pylorus. The histological organization of the cardia and pylorus is similar to that in other fish species, but the organization of the corpus is distinct. The cell bodies of the epithelial cells of the corpus are located in the capillary mesh, while their flattened extensions cover the adjacent capillaries. This specialization reduces the thickness of the blood-air interface, which may influence the diffusion of gases in the stomach. Some epithelial cells in the stomach corpus contain numerous lamellar bodies. It is suggested that these produce a substance similar in function to the lung surfactant of Dipnoi, certain Amphibia, and Mammalia.

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Faculty Opinions recommendation of Rab38 targets to lamellar bodies and normalizes their sizes in lung alveolar type II epithelial cells.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13370058.14740214 ◽

2011 ◽

Author(s):

Matthias Ochs ◽

Christian Mühlfeld

Keyword(s):

Epithelial Cells ◽

Alveolar Type ◽

Type Ii ◽

Lamellar Bodies

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The Transition to Air Breathing in Fishes:: I. Environmental Effects on the Facultative Air Breathing of Ancistrus Chagresi and Hypostomus Plecostomus Loricariidae

Journal of Experimental Biology ◽

10.1242/jeb.96.1.53 ◽

1982 ◽

Vol 96 (1) ◽

pp. 53-67 ◽

Cited By ~ 1

Author(s):

JEFFREY B. GRAHAM ◽

TROY A. BAIRD

Keyword(s):

Fish Species ◽

Environmental Effects ◽

Breathing Rate ◽

Breathing Frequency ◽

Rate Reduction ◽

Air Breathing ◽

Aquatic Respiration ◽

Saturated Water ◽

Important Regulator ◽

Hypoxia Acclimation

In response to progressive aquatic hypoxia, the armoured loricariid catfishes Ancistrus chagresi and Hypostomus plecostomus become facultative air-breathers and utilize their stomachs as accessory air-breathing organs. Hypostomus initiates air breathing at a higher aquatic O2 tension (Pw, Ow, O2) than does Ancistrus (60 v. 33 mmHg). Once begun, the air-breathing frequencies of both species increase with decreasing Pw, Ow, O2; the frequency of Ancistrus, however, is greater than and increases more with hypoxia than does that of Hypostomus, which appears to be a more efficient air breather. Hypoxia acclimation reduces the air-breathing rate of both species. A larger rate reduction occurs in Ancistrus, which, however, continues to require more frequent breaths than Hypostomus. Hypoxia acclimation does not affect the air-breathing threshold of either species, suggesting that external O2 receptors initiate facultative air breathing. In progressive aquatic hypercapnia Ancistrus has a lower air-breathing CO2 threshold (8.7 mmHg) than Hypostomus (12.8 mmHg). However, in some tests, individual fish of both species did not initiate air breathing even at Pw, COw, CO2 as high as 21 mmHg. Also, air breathing evoked by hypercapnia was short-lived; both species quickly compensated for this gas and resumed exclusively aquatic respiration within a few hours of exposure. Thus, CO2 is not an important regulator of air breathing in these species. Between 25 and 35 °C, the Pw, Ow, O2 air breathing threshold of Ancistrus is temperature-independent, but air-breathing frequency increases with temperature. Ancistrus and Hypostomus do not breathe air in normoxic (air-saturated) water; their air-breathing responses are evoked by environmental hypoxia. This is fundamentally different from other fish species that breathe air in normoxia in order to meet heightened metabolic demands. Also, the facultative air-breathing adaptations of Ancistrus and Hypostomus differ in scope and magnitude from those utilized by species that breathe air in nor-moxia and adapt to hypoxia by increasing air-breathing rate.

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Evidence for herbaceous seed dispersal by small-bodied fishes in a Pantanal seasonal wetland

Brazilian Journal of Biology ◽

10.1590/bjb.2014.0089 ◽

2014 ◽

Vol 74 (3) ◽

pp. 588-596 ◽

Cited By ~ 8

Author(s):

RML Silveira ◽

B Weiss

Keyword(s):

Seed Dispersal ◽

Digestive Tract ◽

Plant Species ◽

Fish Species ◽

Seed Bank ◽

Aluminum Foil ◽

Soil Mass ◽

Fecal Material ◽

Sampling Area ◽

Intestinal Contents

We analysed the germination of seeds after their passage through the digestive tract of small floodplain fishes. Samples were collected in five open flooded fields of the northern Pantanal in March 2011. All fishes were sacrificed and their intestinal contents were removed. The fecal material was weighed and stored at 4°C in a GF/C filter wrapped in aluminum foil. The material was then transferred to a receptacle containing sterilised soil from the sampling area. The fecal samples were kept in a germination chamber for 68 days and then transferred to a greenhouse for another 67 days. We collected a total of 45 fish species and 1014 individuals which produced a total amount of 32g of fresh fecal mass and 11 seedlings. We were able to identify six seedlings: two Banara arguta, two Steinchisma laxa, one Hymenachne amplexicaulis and one Luziola sp.. The fish species that produced samples with seedlings were Astyanax assuncionensis, Metynnis mola, Plesiolebias glaucopterus, Acestrorhyncus pantaneiro and Anadoras wendelli. With the exception of B. arguta the remaining plant species and all fish species were not known to be associated with the seed dispersal process of these plants. We found a ratio of 0.435 seedlings.g–1 of fresh fecal material, which is 100 times higher than the amount of seedlings encountered in fresh soil mass (92,974 grams) in seed bank studies conducted in the same study area. In particular, Astyanax assuncionensis and Metynnis mola were among the most frequent and most abundant fish taxa in the area. Together with the high seed concentration in the fish fecal material, this evidence allows us to conclude that such fish species may play an important role in seed dispersal in the herbaceous plants of the Pantanal.

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Macrophages and epithelial cells of the thymus gland. An ultrastructural study in the natterjack, Bufo calamita

Tissue and Cell ◽

10.1016/0040-8166(89)90022-0 ◽

1989 ◽

Vol 21 (1) ◽

pp. 69-81 ◽

Cited By ~ 3

Author(s):

M.G. Barrutia ◽

M. Torroba ◽

M.J. Fernandez ◽

A. Vicente ◽

A.G. Zapata

Keyword(s):

Epithelial Cells ◽

Ultrastructural Study ◽

Thymus Gland ◽

Bufo Calamita

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THE GROSS AND MICROSCOPIC ANATOMY OF THE DIGESTIVE TRACT OF THE OYSTER CRASSOSTREA VIRGINICA (GMELIN)

Canadian Journal of Zoology ◽

10.1139/z57-026 ◽

1957 ◽

Vol 35 (3) ◽

pp. 325-347 ◽

Cited By ~ 293

Author(s):

Barbara L. Shaw ◽

Helen I. Battle

Keyword(s):

Epithelial Cells ◽

Digestive Tract ◽

Crassostrea Virginica ◽

Atlantic Coast ◽

Dorsal Surface ◽

Adductor Muscle ◽

Posterior Chamber ◽

Microscopic Anatomy ◽

The North ◽

Cytoplasmic Processes

The gross and microscopic anatomy of the digestive tract of Crassostrea virginica (Gmelin), the common oyster of commerce of the North Atlantic Coast, is described. The dorsoventrally compressed mouth bounded by two pairs of labial palps leads into a crescentic oesophagus, thence to the anterior chamber of the stomach from which a complex caecum extends into anteriorly and posteriorly directed spiral appendices. The posterior chamber of the stomach bears a chondroid gastric shield and leads into an elongated chamber which is incompletely divided by two typhlosoles into a style-sac and mid-gut. The intestine is divisible into ascending, median, and descending limbs, the latter merging into the rectum which terminates on the dorsal surface of the adductor muscle. Extensively branched tubular digestive diverticula exit from the stomach by a series of ducts along the margin of the caecum and the posterior stomach. The complete digestive tract is lined by a simple columnar epithelium which is ciliated throughout with the exception of the upper lip or fused external palps, the lower side of the gastric shield in the posterior stomach, and the tubules of the digestive diverticula. Mucous secreting and eosinophilic epithelial cells occur in varying numbers along the course of the tract. Phagocytes are present between the lining epithelial cells, among the peripheral collagenous and muscle fibers, as well as in the lumen of the tract. The gastric shield is shown to be intimately attached to the underlying epithelium by a central clip as well as by minute cytoplasmic processes. The anatomical relationships are compared with various lamellibranchs including the Chilean oyster, Ostrea chilensis Philippi; the European oyster, Ostrea edulis L.; and the Portuguese oyster, Gryphea angulata Lamarck.

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Air-breathing during activity in the fishes amia calva and lepisosteus oculatus

Journal of Experimental Biology ◽

10.1242/jeb.201.7.943 ◽

1998 ◽

Vol 201 (7) ◽

pp. 943-948 ◽

Cited By ~ 3

Author(s):

C G Farmer ◽

D C Jackson

Keyword(s):

Oxygen Consumption ◽

Fish Species ◽

Aquatic Habitats ◽

Air Breathing ◽

Spotted Gar ◽

Water Oxygen ◽

Rate Of Oxygen Consumption ◽

Amia Calva ◽

Lepisosteus Oculatus ◽

Air Hole

Many osteichthyan fishes obtain oxygen from both air, using a lung, and water, using gills. Although it is commonly thought that fishes air-breathe to survive hypoxic aquatic habitats, other reasons may be more important in many species. This study was undertaken to determine the significance of air-breathing in two fish species while exercising in oxygen-rich water. Oxygen consumption from air and water was measured during mild activity in bowfin (Amia calva) and spotted gar (Lepisosteus oculatus) by sealing a fish in an acrylic flume that contained an air-hole. At 19-23 degreesC, the rate of oxygen consumption from air in both species was modest at rest. During low-level exercise, more than 50 % of the oxygen consumed by both species was from the air (53.0+/-22.9 % L. oculatus; 66.4+/-8.3 % A. calva). <P>

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