Localization of xenopsin and xenopsin precursor fragment immunoreactivities in the skin and gastrointestinal tract of Xenopus laevis

1992 ◽  
Vol 270 (2) ◽  
pp. 257-263 ◽  
Author(s):  
Kirsten C. Sadler ◽  
Charles L. Bevins ◽  
Jane C. Kaltenbach
Keyword(s):  
Gastrointestinal Tract ◽  
Xenopus Laevis

Differential expression of the TFF-peptides xP1 and xP4 in the gastrointestinal tract of Xenopus laevis

1997 ◽  
Vol 291 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Wolfgang Jagla ◽  
Antje Wiede ◽  
Sabine K�lle ◽  
W. Hoffmann
Keyword(s):  
Gastrointestinal Tract ◽  
Xenopus Laevis ◽  
Differential Expression ◽  
Tff Peptides

Distribution and effects of PACAP, VIP, nitric oxide and GABA in the gut of the African clawed frog Xenopus laevis

2002 ◽  
Vol 205 (8) ◽  
pp. 1123-1134 ◽  
Author(s):  
Catharina Olsson
Keyword(s):  
Nitric Oxide ◽  
Nervous System ◽  
Gastrointestinal Tract ◽  
Xenopus Laevis ◽  
Myenteric Plexus ◽  
Nerve Cells ◽  
Nerve Fibres ◽  
African Clawed Frog ◽  
The Mean ◽  
Clawed Frog

SUMMARY The distribution and possible effects on gastrointestinal motility of pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal polypeptide (VIP), nitric oxide and γ-amino-butyric acid(GABA) were investigated in the African clawed frog (Xenopus laevis)using immunohistochemistry and in vitro strip preparations. PACAP-and VIP-immunoreactive nerve fibres were common in the myenteric plexus as well as in the longitudinal and circular muscle layers all along the gastrointestinal tract. Double labelling demonstrated a close correlation between PACAP and VIP immunoreactivities, indicating that the two neurotransmitters are colocalised within the enteric nervous system. Occasionally, PACAP- and VIP-positive nerve cell bodies were seen in the myenteric or submucous plexa. In addition, VIP immunoreactivity coexisted with helospectin immunoreactivity. Nitric oxide synthase (NOS)-immunoreactive nerve cells were found in the myenteric plexus at an average density for the whole gastrointestinal tract of 4584±540 cells cm-2. The NOS-immunoreactive nerve cells were usually multipolar with an average size of 11.3±3.7 × 23.2±6.6 μm. Some NOS-immunoreactive nerve fibres were VIP-immunoreactive but not all VIP-positive fibres showed NOS immunoreactivity. GABA immunoreactivity was found in nerve fibres and nerve cells in the myenteric plexus of all regions of the gut. Few GABA-immunoreactive nerve fibres were VIP-immunoreactive. PACAP 27, VIP,sodium nitroprusside (a nitric oxide donor; NaNP) and GABA caused similar responses on spontaneously contracting circular preparations of the cardiac stomach of X. laevis. The mean force developed was decreased, mainly by a reduction in resting tension, while the amplitude of contractions was not necessarily affected. The NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) increased the mean force developed, indicating a nitrergic tone in the preparations. In contrast, PACAP 27, VIP, NaNP, GABA and L-NAME had no significant effect on longitudinal strip preparations from the duodenum. These results indicate that PACAP, VIP, nitric oxide and GABA, which are known to be important inhibitory neurotransmitters in other vertebrates, are widely spread in the enteric nervous system of Xenopus laevis and may be involved in the inhibitory control of gastric motility. Although no effect of PACAP,VIP, nitric oxide or GABA on the longitudinal strips of the duodenum was seen in this study, this does not rule out the possibility that they might play an important role in controlling intestinal motility as well.

Structure of two cDNAs encoding cholecystokinin precursors from the brain of Xenopus laevis

1995 ◽  
Vol 14 (3) ◽  
pp. 357-364 ◽  
Author(s):  
C Wechselberger ◽  
G Kreil
Keyword(s):  
Gastrointestinal Tract ◽  
Xenopus Laevis ◽  
Cdna Library ◽  
Genes Encoding ◽  
Skin Secretions ◽  
Cloned Cdna ◽  
The Brain

ABSTRACT The skin secretions of many frogs, including Xenopus laevis, contain caerulein, a peptide related to mammalian cholecystokinin. We have screened a cDNA library prepared from the brain of this frog using a cloned cDNA encoding one of the caerulein precursors as a probe. Two clones were isolated which contained inserts encoding cholecystokinin precursors. It was found that the predicted precursor polypeptides resembled their mammalian counterparts rather than the caerulein precursors from the same species. The corresponding mRNAs of different size encoding the Xenopus cholecystokinin precursors are expressed in brain and in the gastrointestinal tract, but not in skin. The smaller mRNA was also detected in lung. These data demonstrate that a polypeptide homologous to mammalian cholecystokinin precursors was present early in the evolution of vertebrates. The possible evolution of the genes encoding the more complex caerulein precursors is discussed.

Habitat Association of Klebsiella Species

1985 ◽  
Vol 6 (2) ◽  
pp. 52-58 ◽  
Author(s):  
Susan T. Bagley
Keyword(s):  
Drinking Water ◽  
Gastrointestinal Tract ◽  
Surface Waters ◽  
Industrial Effluents ◽  
Opportunistic Pathogen ◽  
Habitat Associations ◽  
Habitat Association ◽  
Klebsiella Species ◽  
Almost All ◽  
Polluted Waters

AbstractThe genus Klebsiella is seemingly ubiquitous in terms of its habitat associations. Klebsiella is a common opportunistic pathogen for humans and other animals, as well as being resident or transient flora (particularly in the gastrointestinal tract). Other habitats include sewage, drinking water, soils, surface waters, industrial effluents, and vegetation. Until recently, almost all these Klebsiella have been identified as one species, ie, K. pneumoniae. However, phenotypic and genotypic studies have shown that “K. pneumoniae” actually consists of at least four species, all with distinct characteristics and habitats. General habitat associations of Klebsiella species are as follows: K. pneumoniae—humans, animals, sewage, and polluted waters and soils; K. oxytoca—frequent association with most habitats; K. terrigena— unpolluted surface waters and soils, drinking water, and vegetation; K. planticola—sewage, polluted surface waters, soils, and vegetation; and K. ozaenae/K. rhinoscleromatis—infrequently detected (primarily with humans).

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

Keratinocyte growth factor binds to collagens of the gastrointestinal tract: Identification of the collagen binding structure

2001 ◽  
Vol 120 (5) ◽  
pp. A695-A695
Author(s):  
M RUEHL ◽  
I SCHOENFELDER ◽  
R FARNDALE ◽  
G KNIGHT ◽  
R SOMASUNDARAM ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Growth Factor ◽  
Keratinocyte Growth Factor ◽  
Collagen Binding ◽  
Binding Structure
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