Aurora Pederzoli

Immunocytochemical evidence for ACTH- and β-endorphin-like molecules in phagocytic blood cells of urodelan amphibians

Using immunocytochemical procedures and RIA tests, the presence of immunoreactive ACTH and beta-endorphin molecules in the basophils and neutrophils of urodelan amphibians (Salamandra s. salamandra, Triturus c. carnifex, Speleomantes imperialis) has been established. Moreover, it was observed that not only neutrophils but also basophils have phagocytic activity. The findings reported suggest that: 1) a relationship exists between the immune and neuroendocrine systems, and 2) the opioid-like molecules play a physiological role in the process of phagocytosis. Indeed, ACTH increases the phagocytic activity.

Microarthropod communities in soil treated with atrazine

Abstract The effect of atrazine on soil microarthropod populations was studied in an experimental field cultivated with maize. Three doses of herbicide (2, 4, 6 Kg/ha) were tested in three different periods and on four layers. Controls were employed. Collembola and Oribatid mites were studied at species-level. The number of microarthropod specimens in the treated plots was not significantly different from that in the control plots.

Histomorphological and cytochemical changes induced in the liver of goldfish Carassius carassius var. auratus by short-term exposure to lead

The cellular and molecular effects of experimental lead intoxication (5 mg l-1/24 h and 48 h) were studied in hepatocytes of Carassius carassius var. auratus. Significant lead storage was not detected by atomic absorbance spectroscopy after treatment. Cell morphology appeared only poorly impaired. A decrease of glycogen content was observed. Glycolysis, Krebs cycle and pentose shunt were altered in their enzymatic activities. Lysosomal activities were strongly increased. All enzymatic activities tested were altered 24 h after lead treatment.

Immunolocalisation of vasoactive intestinal peptide and substance P in the developing gut of Dicentrarchus labrax (L.)

This study was carried out on the sea bass (Dicentrarchus labrax) to follow, during development, the appearance and distribution of substance P (SP) and vasoactive intestinal peptide (VIP), which act on gut motility. The results suggest that SP and VIP play an important role as neuromodulators, influencing the motility of the digestive tract starting from the early stages of gut development, even prior to exotrophic feeding. In the peptidergic nervous system, the appearance of immunoreactivity to SP began at the rectum and followed a distal to proximal gradient, whereas for VIP, it began proximally and progressed along a proximal to distal gradient. The two peptides also appeared in gut epithelial cells. In some regions, all the cells were positive. From this distribution of positive cells, we conclude that these peptides may also have other roles, besides being neurotransmitters in the enteric nervous system and hormones of the gastro-entero-pancreatic system. VIP and SP might have paracrine and/or autocrine activity in the physiological maturation of the gut epithelium, as it has already been hypothesised for other peptides.

Effects of acute experimental pollution by lead on some haematological parameters in Carassius carassius (L.) var. auratus

Abstract Several haematological (RBC, WBC and thrombocyte count, HGB, HCT, MCV, MCH, MCHC) and serological parameters (lead blood content, ALA‐D, glucose, GOT, GPT, Try, Chol, TP, Na+, K+, Cl‐, Ca++) have been assayed in specimens of Carassius carassius (L.) var. auratus submitted to sublethal acute exposure to lead (5 ppm., 24 and 48 hrs). The following differences were observed between control and treated samples: the number of RBC was decreased after 48 hrs of treatment; haematocrit, haemoglobin percentage and MCHC were also decreased. Glucose and lead concentrations in blood were increased, whereas ALA‐D, transa‐minases and calcium were decreased. No significant variations in the other studied parameters were observed.

Immunolocalization of corticotropin-releasing factor (CRF) and corticotropin-releasing factor receptor 2 (CRF-R2) in the developing gut of the sea bass (Dicentrarchus labrax L.).

Our previous data indicated an important role for adrenocorticotropic (ACTH)-like molecules co-operating with macrophages to control the modifications in body homeostasis during the first period of the life of sea bass (up to 30 days post-hatching) before the lymphoid cells have reached complete maturation. The aim of the study was to determine the immunolocalization of corticotropin-releasing factor (CRF), which is a very important mediator of stress-related responses. Our data showed that immunostaining for CRF is localized already at 8 days after hatching in nerve fibers of the gastrointestinal tract wall from the pharynx to the anterior gut, when the larvae are still feeding on yolk. This pattern of immunolocalization appeared similar to that in 24-day-old larvae, but at this stage there were also large cells immunopositive to CRF located in the wall of the midgut and hindgut. Lipopolysaccharide (LPS) treatment, which is a known stimulator of stress hormone responses, did not modify the CRF immunostaining pattern, though it did affect the immunolocalization of the peripheral CRF receptor, i.e. CRF-R2. Immunolocalization of CRF-R2 appeared in nerve fibers of the gut wall in larvae fixed 1h after the end of lipopolysaccharide (LPS) treatment. The present results suggest that CRF plays important autocrine and/or paracrine roles in the early immune responses at the gut level in the larval stages of sea bass (Dicentrarchus labrax L.) as already proposed for ACTH. Moreover, our studies taken together with other research on fish, in comparison with mammals, suggest a phylogenetically old role of CRF in immune-endocrine interactions.

Structure-function relationships in the integument of Salamandra salamandra during ontogenetic development

Morphological, cytological and transport properties of the integument of Salamandra salamandra were investigated during natural ontogenetic development, from birth to adult. Three stages were operationally defined: I, larvae, from birth to metamorphosis; II, metamorphosis (judged externally by the colour change and loss of the gills); and III, post‐metamorphosis to adult. Pieces of skin were fixed at various stages for immunocytochemical examinations, and the electrical properties were investigated on parallel pieces. Distinct cellular changes take place in the skin during metamorphosis, and lectin (PNA, WGA and ConA) binding indicates profound changes in glycoprotein composition of cell membranes, following metamorphosis. Band 3 and carbonic anhydrase I (CA I) were confined to mitochondria‐rich (MR)‐like cells, and were detected only in the larval stage. CA II on the other hand, was detected both in MR‐like and in MR cells following metamorphosis. The electrical studies show that the skin becomes more tight (transepithelial resistance increases) upon metamorphosis, followed by manifestation of amiloride‐sensitive short‐circuit current (I sc) indicating that functional Na+ uptake has been acquired. The skin of metamorphosed adults had no finite transepithelial Cl− conductance, and band 3 was not detected in its MR cells. The functional properties of MR‐like and MR cells remain to be established.

Arylsulphatase activity and cerebroside sulphates in the frog oviduct during the reproductive cycle

SummaryThe presence of arylsulphatase A and cerebroside sulphates in different tracts ofRana esculenta oviduct during different phases of the reproductive cycle were investigated by histochemical and biochemical procedures. The results indicate that enzyme activity shows seasonal fluctuations connected with the phase of the sexual cycle. The concentrations of cerebroside sulphates (the natural substrates of arylsulphatase A) is related to the activity of this hydrolytic enzyme. The role of arylsulphatase A activity in regulating the substrate concentration, and particularly that of sulphatides, is discussed.

Shift of optimal pH in arylsulphatase from mollusca depending on temperature

Abstract 1. 1. Arylsulphatase activity of Helix pomatia and Patella vulgata have been tested at different temperatures. 2. 2. The maximum pH activity changes depending on temperature; by increasing temperature a shift of pH maximum has been observed in both arylsulphatases. 3. 3. The influence of 4-nitrophenylphosphate (4-NPP), a synthetic inhibitor phosphoester, has been also studied at different temperatures. 4. 4. Differences are evident between inhibited and non-inhibited arylsulphatase from Helix pomatia and Patella vulgata . 5. 5. By comparing arylsulphatase from Helix and Patella with that of human liver, arylsulphatase from Helix resembles arylsulphatase type A , but it is not inhibited by AgNO 3 ; arylsulphatase from Patella migrates faster than Helix (as human arylsulphatase B does), but is not inhibited by NaCl, inhibitor of arylsulphatase B.

Cytochemical and immunocytochemical investigations on epidermal mitochondria-rich cells in Salamandra salamandra salamandra (L.) larvae

In the present study we set out to investigate the expression of E-cadherin, N-cadherin, beta 1-integrin, fibronectin and vitronectin in the mitochondria-rich cells (MRC) of the skin of Salamandra salamandra salamandra. Moreover MRC were stained with five lectins (Triticum vulgaris; Dolichos biflorus; Glycine max; Arachis hypogaea and Canavalia ensiformis). Larval MRC expressed both adhesion molecules and extracellular matrix glycoproteins and bound all lectins tested. Juvenile MRC did not react with the antisera utilized, but they stained with the lectins. Both the lectins and the regulatory molecules proved to be good cytochemical markers for distinguishing morphologically differentiated MRC during the larval life of Salamandra salamandra salamandra. The adhesion molecules and matrix glycoproteins are of great utility for maintaining the correct tissue architecture. In Salamandra salamandra salamandra larvae these molecules may be crucial for stability and for the correct localization and fate of all skin elements, including specialized cells such as larval MRC.