Acta Zoologica

Kar, Satyabrata; Naik, Dhruba Raj

doi: 10.1111/j.1463-6395.1987.tb00883.xpmid: N/A

Cells of the pituitary pars distalis (PD) and pars intermedia (PI) in the frog Rana limnocharis have been identified by an unlabelled antibody enzyme method using antisera developed in rabbit against mammalian hypophysial hormones. On the basis of their immunoreactivity, six types of cells, viz. thyrotropic (TSH), gonadotropic (GTH), prolactin (PRL), growth hormone (GH), corticotropic (ACTH) and melanotropic (MSH), cells have been recognized. GTH and PRL cells are distributed throughout the PD. GH cells usually occur in the anterodorsal and central region of the gland. Immunoreactive TSH cells are fewer in number and are localized in the ventromedian region of the PD. Cells showing immunoreactivity to ACTH 1–24 antiserum are encountered in the rostroventral part of the PD. Cells of the PI also show immunoreactivity to ACTH 1–24 antiserum. PI cells cross‐react with α‐MSH antiserum at all dilutions up to 1: 50 000. However, when the same antiserum was used at dilutions up to 1: 20 000, the ACTH cells of the PD also showed cross‐reactivity.

Sensenbaugh, Terry

doi: 10.1111/j.1463-6395.1987.tb00884.xpmid: N/A

The larva of Loxosoma pectinaricola Franzén has been studied using scanning and transmission electron microscopy. The embryo develops surrounded by an egg envelope attached to the brood chamber. The newly released larva measures about 100 μm in length and is characterized by a prominent apical organ, stalked vesicles, paired lateral sense organs and a prototroch. The apical organ consists of at least four cell types: (1, 2) two types of ciliated cells, (3) vacuolated cells and (4) myoepithelial cells. The apical organ and frontal ganglion are tightly juxtaposed in the upper tier of the episphere. The stalked vesicles each consisting of two cells are unique evaginations of the epidermis. There are about twenty stalked vesicles with a maximum diameter of about 20.0 μm. The ciliated, knob‐shaped, paired lateral sense organs are situated fronto‐laterally on the episphere. The prototroch is comprised of a row of contiguous prototroch cells each containing about eighteen long cilia. The apical organ, frontal ganglion and paired lateral sense organs are suggested to be sensory structures that play an important role in active locomotion, settlement site selection and metamorphosis.

Lindroos, Paula; Wikgren, Marianne

doi: 10.1111/j.1463-6395.1987.tb00885.xpmid: N/A

The extracellular matrix (ECM) was studied in the turbellarians Polycelis nigra and Microstomum lineare, the cestode Diphyllobothrium dendriticum and the trematode Dicrocoelium dendriticum. Routine LM staining methods for connective tissue gave positive results only in P. nigra. Positive staining reactions were observed in the subepithelial basal lamina, around the pharynx and as strings in the tissues. Peroxidase‐anti‐peroxidase and immunofluorescence methods were used to identify fibronectin. Positive results were obtained in all species. Positive reactivity to anti‐fibronectin was observed in the subepithelial basal lamina and as a thin network between the cells of the tissues. Some intracellular reactivity occurred, but the cell type was not identified. In M. lineare a strong positive reactivity was observed in the regenerating area.

Reuter, Maria; Palmberg, Irmeli

doi: 10.1111/j.1463-6395.1987.tb00886.xpmid: N/A

The gastrodermal cell types of Microstomum lineare (Turbellaria, Macrostomida) were studied by electron microscopy. Their immunoreactivity (IR) to bovine pancreatic peptide (BPP), FMRF‐amide and vasotocin, somatostatin, neurotensin, ACTH, CCK, bombesin, secretin, gastrin/CCK and insulin antisera was tested by light microscopic immunocytochemical methods. In addition to granular club cells and phagocytic cells, neurons and neoblasts occur in the gastroderm of this turbellarian species. This is the first observation of neurons in the gastroderm of a flatworm. Dense‐core vesicles (70–100 nm diameter), electron lucent cytoplasm and numerous Golgi complexes characterize the neurons. Unpolarized two‐way synapses, neuromuscular junctions and polarized chemical synapses can be observed in the gastroderm. Neoblasts with large nuclei and scanty cytoplasm and differentiating cells containing clusters of basal bodies occur next to the basal lamina of the gastroderm. BPP‐like, FMRF‐amide‐like and vasotocin‐like immunoreactivity is demonstrated in the gastroderm. Both BPP and FMRF‐amide IR is restricted to the basal cytoplasm of the granular club cells, while a different location for IR to vasotocin antiserum is observed. The status of the neuronal cell in the gastroderm of M. lineare is discussed in relation to endocrine (paracrine) cells and neurons in the gastroderm of invertebrates.

Andresen, J.H.; Ishimatsu, A.; Johansen, K.; Glass, M.L.

doi: 10.1111/j.1463-6395.1987.tb00887.xpmid: N/A

The unique anatomy of the double ventral aorta outflow system in the air breathing teleost Channa argus (Ophiocephalus) showing an anterior and posterior ventral aorta is described. The marked trabeculation of the ventricle and bulbus arteriosus and the arrangement of central veins are used as a basis for the hypothesis that Channa may selectively channel the well oxygenated blood draining the air breathing organs via the anterior cardinal vein to the posterior ventral aorta, which forms the systemic arterial circulation. An angiocardiographic technique was used to test this hypothesis, as well as to delineate the functional role of the heart chambers in the cardiac cycle. No reflux of contrast to the sinus venosus during atrial filling and no ventricular filling before atrial contraction were apparent, which makes the atrium the main determinant of the ventricular end‐diastolic volume. Ventricular contraction left a small or no residual volume. The ventricular ejectate was initially nearly completely absorbed by the very elastic bulbus arteriosus, acting as a pressure chamber (Windkessel) stabilizing and prolonging ventral aortic blood flow. Contrast medium was not selectively passed from the anterior cardinal vein to the posterior ventral aorta. However, the diameter of this vessel and its density of contrast were greater than in the anterior aorta, suggesting a preference for a greater blood flow from the air breathing organ through the heart to the posterior aorta.

Bjerring, Hans C.

doi: 10.1111/j.1463-6395.1987.tb00888.xpmid: N/A

The orbit of the Upper Devonian piscine osteolepipod Eusthenopteron foordi has a distinct endocranial depression postero‐ventrally at the base of the basipterygoid process and lateral to the hypophysis. Compared with what is known of extant osteolepipods, this depression is a myodomus retractricis bulbi. From the evidence of this myodome for attachment of retractor bulbi musculature, the hypothesis is presented that Eusthenopteron foordi had a palpebra tertia and, as a corollary, that it also had a musculus levator bulbi, a glandula palpebrae tertiae and a ductus nasolacrimalis. These annexal eye structures would have made it possible for this pulmonate fish to leave the water to bask without being dazzled by sunlight.

Hohenleitner, Frank J.; Caso, Louis V.

doi: 10.1111/j.1463-6395.1987.tb00889.xpmid: N/A

Previous reports of tunicate endostyles have suggested that they contain little or no acidic glycoproteins in the glandular zones. The endostyles of Ciona intestinalis and Styela plicata were examined after anhydrous fixation with cyanuric chloride. Polyanions were stained with alcian blue (AB) at pH 2.5 or azure A, while sulfomucins were stained with high‐iron diamine (HID) or AB at pH 1.0. Endostyles were also tested for sensitivity to acid hydrolysis (AH) and saponification. In Ciona zones 2 and 4 sometimes demonstrated positive HID and AB 1.0 responses. Almost invariably zone 6 was AB+ at pH 2.5; zones 2 and 4 were frequently responsive to AB, but less intense. Each of these 3 zones, when AB+, was sensitive to AH. Responses by zones 3 and 5 to AB (pH 2.5), azure A and saponification suggest that these zones contain mostly nuclear material. In secretory zones 2, 4 and 6 histological responses are consistent with the histochemistry of sialomucins. Zones 1 and 8 had sulfated material in the apical edges in both animal groups. Among the fixatives used for Ciona, only anhydrous fixation demonstrated most of the positive responses to polyanion‐sensitive stains.

Reuter, Maria

doi: 10.1111/j.1463-6395.1987.tb00890.xpmid: N/A

A whole mount immunocytochemical (ICC) method has been used for the investigation of immunoreactivity (IR) to the molluscan cardioactive peptide FMRF‐amide, to 9 vertebrate neuropeptides—leu‐enkephalin, growth hormone‐releasing factor (GRF), urotensin I, urotensin II, bovine pancreatic peptide (BPP), β‐endorphin, substance P, secretin and insulin—and to the bioamine 5‐HT in the nervous system (NS) of the trematode Gyrodactylus salaris belonging to the taxon Monogenea. Positive results were obtained using antisera to FMRF‐amide, leu‐enkephalin, urotensin I, GRF and to 5‐HT. The present results are the first documentation of the presence of neuroregulatory peptides and a bioamine in the nervous system (NS) of Monogenea. Differences in the distribution pattern of the IR to the different antisera indicate that different subsets of neurons are revealed. In addition, details of the basic neuroanatomical pattern in monogeneans are confirmed by the whole mount ICC method used in this study. Negative results were obtained with antisera to urotensin II, substance P, β‐endorphin, secretin, insulin and bovine pancreatic polypeptide (BPP).

Pietsch, Arnold; Westheide, Wilfried

doi: 10.1111/j.1463-6395.1987.tb00891.xpmid: N/A

Myzostoma cirriferum Leuckart, 1836 possesses five paired, serially arranged, blindending nephridial organs which are described for the first time. Ultrastructural investigations reveal that each nephridium is composed of three terminal cells and one tubular cell that forms the emission tubule. The central lumen of the individual terminal cells contains six to nine flagella, each of which is surrounded regularly by cytoplasmic rods arranged in parallel. Weir‐like fenestrations in the peripheral wall of the terminal cells make up the connection between the central lumina and the extracellular space around the nephridial organ. The canal of the emission tubule possesses cilia, microvilli and cytoplasmic structures, suggesting involvement of this cell with active transport and storage. It opens into the cuticle at the ventral surface of the animal.