Unusually high rates of metabolism of DHT in cytosols of the quail uropygial gland

The metabolism of DHT in the cytosol of the quail uropygial gland was found to be so high that the steroid was almost completely inactivated within 2 hours of incubation at 0 C. In these conditions, DHT cannot be used for the characterization of androgen receptors. By contrast, R 1881 and mibolerone, which are not metabolized, can be used as alternative ligands. Moreover, the extremely high metabolism of DHT questions the physiologic role of this steroid in the quail uropygial gland.     

Genetic structure of the population of Sicily.

Genetic heterogeneity within Sicily was investigated on the basis of ACP1, ADA, ESD, GLO1, PGD, PGM1, PGM2, SODA, ABO, and MN gene frequencies, and compared to those of other regions of Italy for which these same loci have been examined. Correspondence analysis revealed no differences within the island, at least at the provincial level, but showed genetic differentiation among Italian regions, distinctly clustering northern, central, and southern populations, respectively. These data indicate a close relationship between Sicily and southern Italy. In addition, the contribution of Middle Eastern populations to the gene pool of Sicily was evident.     

Regional and Ontogenic Expression of the NMDA Receptor Subunit NR2D Protein in Rat Brain Using a Subunit-Specific Antibody

Abstract: A polyclonal antibody for the NMDA receptor subunit NR2D has been developed that identifies an ∼160-kDa band on immunoblots from NR2D transfected cells and CNS tissues. No cross-reactivity is seen with other NMDA receptor subunits. The NR2D receptor subunit is N -glycosylated in both brain and transfected cells. Transfected cells expressing NR2D are immunofluorescently labeled, whereas untransfected cells or cells transfected with other NMDA receptor subunit cDNAs are not. Similarly, the NR2D subunit is selectively and quantitatively immunoprecipitated, whereas the NR1, NR2A, or NR2B subunit is not. The relative densities of the NR2D subunit in nine areas of postnatal day 7 and adult rat brains have been determined by quantitative immunoblotting. NR2D was expressed at highest levels in the thalamus, midbrain, medulla, and spinal cord, whereas intermediate levels of this subunit were found in the cortex and hippocampus. Low or undetectable levels were seen in the olfactory bulb, striatum, and cerebellum. Following a peak after the first week of birth, NR2D protein levels decreased by about twofold in adulthood in all rat brain regions examined. More complete ontogenic profiles were determined for the diencephalon, telencephalon, and spinal cord where similar ontogenic patterns were seen. NR2D protein is present at high levels at embryonic stages of development, rises to a peak at postnatal day 7, and decreases but remains measurable during late postnatal life. This study demonstrates the generation and characterization of an antibody selective for the NR2D NMDA receptor subunit as well as a determination of the distribution and ontogenic profile of this subunit in rat brain. The results suggest that native NMDA receptors containing the NR2D subunit may have functional roles not only in the young brain but also in adult brain.     

Form changes in the sea bass, Dicentrarchus labrax (Moronidae: Teleostei), after acclimation to freshwater: an analysis using shape coordinates

Synopsis Morphological changes in the sea bass, Dicentrarchus labrax (Perciformes: Moronidae), were investigated after an experimental acclimation trial to freshwater. The sea bass is an euryhaline species occurring in the Mediterranean and west Atlantic from 30° N to 55° N. Part of the offspring of a pool of breeders was acclimated to freshwater at 9 months of age while maintaining the original stock in marine water. The effect of acclimation to freshwater over the entire form of the fish was studied through geometric morphometrics (shape coordinates). Changes in the form were shown graphically as landmark displacements though age classes 7,12, 15, 19 and 24 months and were discussed in the light of integrated growth. A significantly faster growth in freshwater was detected. Shape coordinates analyzed through multivariate statistics show that significant differences in shape arise after acclimation to freshwater. Moreover, the uniform component of shape change reveals a major effect of stretching or compression perpendicular to the body axis which is common and conservative in both trials. Differences are discussed in terms of selection and ecophenotypism.     

Aerobiological monitoring for fungal spores in a rehabilitation hospital in Northern Italy

In the setting of an aerobiological study of confined environments and environmental prevention of nosocomial infections, aerobiological monitoring of 22 areas in Montescano Medical Rehabilitation Centre (Pavia) was performed in three different months: February, May, and August, 1994. A Lanzoni 3000 spore trap was used for the monitoring. Examination of the results showed that, in the environments monitored, the indoor presence of fungi increased progressively over the three periods considered. The behaviour of individual genera of fungi differed. In the winter periodPenicillium andAspergillus were the most commonly encountered genera.Cladosporium was the dominant genus from the spring to the summer while the yeasts had their maximum counts in the spring morning. The use of air conditioning, combined with the low air exchange between outdoors and indoors in some of the environments certainly played a part in the low concentrations of these latter aerofungi.     

Induction of histamine release from rat mast cells by bradykinin analogues

Independently of their agonistic or antagonistic activity on different isolated tissue preparations, the kinin analogues investigated induce histamine release on rat peritoneal mast cells. The effectivity of most compounds is 10 to 100 times higher than that of bradykinin. Beside the positively charged amino acids, the elongation at the N-terminus with hydrophobic amino acids and the replacement of amino acids in the bradykinin sequence (especially at position 7) with aromatic residues is important for a high histamine-releasing activity.     

Diurnal variation of corticotropin-releasing factor binding sites in the rat brain and pituitary

Summary 1. Corticotropin-releasing factor (CRF) is thought to be involved in the regulation of the diurnal activity of the hypothalamus-pituitary-adrenal (HPA) axis and to act as a neurotransmitter in the brain. To date it is unknown whether the binding sites of the central CRF system are subject to diurnal variations. 2. We measured the number of CRF binding sites over the course of a complete 24-hr light-dark cycle in the pituitary, amygdala, bed nucleus of the stria terminalis (BNST), cingulate cortex, visceral cortex, paraventricular nucleus of the hypothalamus, hippocampus, and locus ceruleus of rats byin vitro receptor autoradiography with iodinated ovine CRF. A 24-hr time course was also established for plasma CRF and corticosterone. 3. The diurnal pattern of plasma CRF does not correlate with the pattern of plasma corticosterone. Within the brain, CRF binding in the basolateral nucleus of the amygdala showed a U-shaped curve with maximum levels in the morning and a wide hallow between 1500 and 0100. A biphasic profile with a small depression in the afternoon and a more pronounced depression in the second half of the activity period is characteristic for the other brain areas and the pituitary. The profile for the pituitary correlates with those for the BNST and the area of the locus ceruleus. Furthermore, the diurnal pattern of CRF binding sites in the BNST correlates with that of the hippocampus, and the daytime pattern of the visceral cortex is similar to that of both the hippocampus and the BNST. 4. Since the CRF-binding profiles in the brain and the pituitary clearly differ from the profiles of both plasma CRF and corticosterone, one may assume that the diurnal pattern of central CRF binding sites is not directly coupled to the activity of the HPA axis.     

The biosynthesis of the lantibiotics epidermin,gallidermin, Pep5 and epilancin K7

Lantibiotics are antibiotic peptides that contain the rare thioether amino acids lanthionine and/or methyllanthionine. Epidermin, Pep5 and epilancin K7 are produced by Staphylococcus epidermidis whereas gallidermin (6L-epidermin) was isolated from the closely related species Staphylococcus gallinarum. The biosynthesis of all four lantibiotics proceeds from structural genes which code for prepeptides that are enzymatically modified to give the mature peptides. The genes involved in biosynthesis, processing, export etc. are found in gene clusters adjacent to the structural genes and code for transporters, immunity functions, regulatory proteins and the modification enzymes LanB, LanC and LanD, which catalyze the biosynthesis of the rare amino acids. LanB and LanC are responsible for the dehydration of the serine and threonine residues to give dehydroalanine and dehydrobutyrine and subsequent addition of cysteine SH-groups to the dehydro amino acids which results in the thioether rings. EpiD, the only LanD enzyme known so far, catalyzes the oxidative decarboxylation of the C-terminal cysteine of epidermin which gives the C-terminal S-aminovinylcysteine after addition of a dehydroalanine residue.Abbreviations Dha 2,3-didehydroalanine - Dhb 2,3-didehydrobutyrine - Lan lanthionine - Melan methyllanthionine     

Cytogenetic effects induced by cytochalasin B in Chinese hamster ovary cells

We determined the kinetics of the induction of chromosomal aberrations and micronuclei (MN) by mitomycin C (MMC, 0.1 µg/ml) in Chinese hamster ovary (CHO) cells treated with cytochalasin B (Cyt-B, 3 µg/ml). In cells treated with Cyt-B as well as with Cyt-B plus MMC the highest yield of binucleated cells was obtained 24 h after treatment. After 40 h of treatment with Cyt-B the frequency of MN in binucleated cells was significantly higher than that observed at previous times in the same cultures as well as in controls. In cultures treated with MMC the frequency of MN increased with time, reaching the highest value at 24 h. The frequency of chromosomal aberrations was also significantly higher in cells treated both with Cyt-B and Cyt-B plus MMC than in controls and exceeded that of MN in parallel cultures. These data confirm the capacity of MMC to induce chromosomal alterations in mammalian cells; in particular they indicate that Cyt-B is able to induce cytogenetic effects in CHO cells. Using immunofluorescence microscopy, after reaction with CREST antikinetochore antibodies, we found that in cells treated with Cyt-B or Cyt-B plus MMC the frequency of MN without kinetochore was, respectively, about 70 and 85%, indicating that under our experimental conditions MN originate mainly from acentric chromatid fragments. Present data suggest that the method based on the blockage of cytokinesis by Cyt-B normally used in the MN assay should be reconsidered.     

Nuclear matrix involvement in sperm head structural organization

Summary— In the sperm nuclei the DNA is packaged into a highly condensed form and is not organized into nucleosome and solenoid but is bound and stabilized mainly by the protamines that arrange the DNA in an almost crystalline state. As demonstrated for somatic cells, the sperm DNA has been reported to be organized in loop domains attached to the nuclear matrix structures. However, the possible role of the sperm head matrix in maintaining the loop organization in absence of a typical nucleosomal structures has not been fully elucidated. By using in situ nick translation at confocal and electron microscope level, we analyzed the organization of the DNAprotamine complex and its association with the sperm nuclear matrix. The data obtained indicate that the chromatin organization in sperm nuclei is maintained during the sperm condensation by means of interactions with the nuclear matrix at fixed sites. The fine stucture of sperm nucleus and of sperm nuclear matrix, investigated on sections and replicas of freeze-fractured specimens, suggests that the lamellar array, observed by freeze-fracturing in the sperm nuclei, could depend on the inner matrix which presents a regular organization of globular structures possibly involved in the maintenance of chromatin domains in highly condensed sperm nuclei also.