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Key enzymes of the kallikrein-kinin system in antarctic teleosts
No full textIn this study, some of the mammalian kallikrein-kinin system (KKS)-like components were identified in two species of Antarctic notothenioid [Chionodraco hamatus (Channichthydae) and 1remato- mus bernacchii (Nothothenidae)]. The kidney and heart were assayed for kallikrein-like activity using the syn- thetic substrate D-Val-Leu-Arg-paranitroanilide. Values expressed as nmol p-nitroanilide/mg proteins, were in C. hamatus 15.51.4 in kidney and heart, respectively, and 15.81 in kid- ney and heart of 1. bernacchii. Kallikrein-like activity was inhibited by aprotinin and phenylmethylsulfonyl fluoride (PMSF). The assay was stable at 20°C. Kininase II-like activity was performed on kidney, gills and heart using the substrate hippuryl-L-histidyl-L- leucine. The activity was inhibited by captopril, and in kidney and gills by high temperatures (20°C and 37°C); in the heart the enzymatic activity was measurable also at 20°C. Bradykinin-like immunoreactive cells were localized by immunohistochemistry in the nephron, in the gills, and in the arterial walls of the heart. These results show that Antarctic teleosts possess elements comparable to those of the KKS, including kallikrein- like, and kininase II-like activities, and the end product of the enzymatic cascade, bradykinin. The enzymatic cascade appears to be fully active only at low temper- atures
Immunohistochemical localisation of FMRF-amide-like peptide in the brain of icefish and red blooded Antarctic Teleosts
No full textThe distribution of Phe-Met-Arg-Phe-NH2 (FMRF-amide) -like immunoreactivity was investigated by indirect immunofluorescence technique using the molluscan FMRF-amide antibody in the brain of icefish (Pagetopsis macropterus and Chionodraco hamatus used as positive control) and red blooded (Trematomus bernacchii, Gymnodraco acuticeps, Histiodraco velifer, Cygnodraco mawsoni) Antarctic Teleosts. Immunoreactive perikarya were localised in the ventral thalamus, in the hypothalamus (preoptic and periventricular regions) and in the intermedioventral rhombencephalon (vagal motor nucleus) as well as in the telencephalon and in the mesencephalon. Positive nerve fibres were seen to project towards the caudal brainstem to reach the rhombencephalon. No differences were observed in the immunopositivity of FMRF-amide new distribution in the Antarctic Teleosts examined. In the icefishes the immunoreaction was stronger than in the hemoglobin-rich Teleosts. The distribution patterns of the FMRF-amide immunostaining suggest that this peptide may play a pivotal role in the cardiovascular regulation in the Antarctic Teleosts
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mitochondria-rich cells in Antarctic fish gills.
No full textWe used transmission and scanning electron microscopy and an antibody to the inner mitochondrial membrane to study the presence and localisation of mitochondria-rich cells in the gills of two Antarctic ®shes, Chionodraco hamatus (Channichthyidae) and Trematomus bernacchii (Nototheniidae). The general morphology of the gills in the two species was slightly dierent: in T. bernacchii the ®lament and secondary lamellae were short and thicker, and mitochondria-rich cells were less numerous than in C. hamatus. In the two species the mitochondria-rich cells, distributed in the secondary and primary epithelium, were of the same morphological type, similar to the -chloride cells of temperate seawater teleosts. The study was carried out to compare the mitochondria-rich cells of Antarctic ®shes to the chloride cells of temperate marine teleosts. Immunolocalisation, using a speci®c antibody to the -subunit of Na+/K+-ATPase, was observed in nu- merous epithelial cells in the interlamellar epithelium and on the secondary lamellae, suggesting an active sodium chloride secretion
Localization of interleukin-1ß mRNA in the cerebral ganglion of the protochordate, Styela plicata
No full textThe Kallikrein- Kinin and the Renin-Angiotensin Systems in the kidney of an african lungfish, Protopterus annectens
No full textSomatostatin in lungfish kidney: an immunohistochemical, autoradiographical and in situ hybridisation study
No full textThe localisation of somatostatin-14 (SST-14) was examined immunohistochemically using the antibody Ab-SST-14 in the kidney of the African lungfish Protopterus annectens. Immunoreactive cells were present in the proximal tubules. In situ hybridisation, using an oligonucleotide probe complementary to mRNA for SST-14 and labeled at the 3'-end with alpha-35S, showed SST-14 mRNA distributed in cells with the same localisation as seen for SST-14 immunoreactive cells. Binding sites for SST-14 were identified with autoradiography using 125I SST-14. Binding sites were concentrated on cells of the proximal tubules. It is suggested that SST-14 may be synthesised in the lungfish mesonephros
Ion transport systems in kidney and urinary bladder of two Antarctic teleosts, Chionodraco hamatus and Trematomus bernacchii
No full textNa+-K+-ClA cotransport and Na+/K+AT- Pase were studied by immunohistochemistry in the kid- ney and urinary bladder of Trematomus bernacchii and Chionodraco hamatus. The activity was correlated to the density of mitochondria. The ®rst segment of the renal proximal tubule was more active than the second one. In T. bernacchii and the temperate marine teleost Pagellus bogaraveo, the immunoreactivity for the antibody to cotransporters and to the -subunit of the sodium pump was stronger than in the ice®sh. This dierence indicates in the kidney of the ice®sh, a weaker secretory activity, a consequent lower osmolarity in the lumen and lower water loss, which correlates well with the need for a greater blood volume in the ice®sh. The epithelium of the urinary bladder in T. bernacchii, where intense im- munostaining was observed, was composed of columnar cells. In C. hamatus the columnar cells, where the im- munostaining was weaker, lined only a portion of the urinary bladder, the other region being composed of cuboidal cells
Identification and distribution of nitric oxide synthase in the brain of adult Antarctic Teleosts
No full textWe investigated the presence of nitric oxide synthase (NOS) in brain of adult Antarctic teleosts by indirect immunofluorescence technique using a synthetic rat neuronal NOS (nNOS) antibody. The following species were examined: Trematomus bernacchii, Gymno- draco acuticeps, Histiodraco velifer, Cygnodraco mawsoni (haemoglobin-rich), Chionodraco hamatus and Pagetop- sis macropterus (haemoglobin-free). Immunoreactive cell bodies were localized in dorsal telencephalon, in hypo- thalamus, in optic tectum of the mesencephalon as well as in Purkinje cells of the cerebellum. No differences were observed in the localization of the nNOS immu- nopositivity in the Antarctic teleosts brains examined and NOS distribution was similar to that described in other teleosts, suggesting that nitric oxide (NO) may also function as a neurotransmitter in the brain of Antarctic teleosts. A strong immunopositivity was observed in the cerebral blood vessels of the icefishes suggesting that NO may play a pivotal role in the regulation of the cerebral blood flow especially in these haemoglobin-free species.We investigated the presence of nitric oxide synthase (NOS) in brain of adult Antarctic teleosts by indirect immunofluorescence technique using a synthetic rat neuronal NOS (nNOS) antibody. The following species were examined: Trematomus bernacchii, Gymnodraco acuticeps, Histiodraco velifer, Cygnodraco mawsoni (haemoglobin-rich), Chionodraco hamatus and Pagetopsis macropterus (haemoglobin-free). Immunoreactive cell bodies were localized in dorsal telencephalon, in hypothalamus, in optic tectum of the mesencephalon as well as in Purkinje cells of the cerebellum. No differences were observed in the localization of the nNOS immunopositivity in the Antarctic teleosts brains examined and NOS distribution was similar to that described in other teleosts, suggesting that nitric oxide (NO) may also function as a neurotransmitter in the brain of Antarctic teleosts. A strong immunopositivity was observed in the cerebral blood vessels of the icefishes suggesting that NO may play a pivotal role in the regulation of the cerebral blood flow especially in these haemoglobin-free species
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