Dolphin ceruloplasmin: the first proteolytically stable mammalian ceruloplasmin.

1. Ceruloplasmin, the blue protein of the plasma of vertebrates, was isolated from dolphin, a marine mammal. The protein showed overall physico-chemical parameters very similar to those of all other mammalian ceruloplasmins. The spectroscopic properties indicated a conservation of the copper binding sites. 2. Non-denaturing electrophoresis revealed a conformation similar to that of other mammalian ceruloplasmins. EPR spectroscopy and calorimetric analyses indicated a three-domain arrangement of the protein typical of "aged" ceruloplasmin. 3. Dolphin ceruloplasmin is the only mammalian ceruloplasmin insensitive to trypsin, plasmin or chymotrypsin. This property, however, does not result in a higher conformational stability of the molecule. Thus, susceptibility of ceruloplasmin to aging is not directly related to the lability to proteases, which is typical of all other mammalian ceruloplasmins so far studied.     

Antibacterial activity of rufloxacin in theStaphylococcus aureus rat granuloma pouch model

The protective effects of rufloxacin againstStaphylococcus aureus-induced infections were compared with those of ciprofloxacin in the granuloma pouch model in the rat. Two strains with different in vitro sensitivity to the drugs were studied. Rufloxacin concentrations persisted longer than ciprofloxacin in the exudate in the pouch cavity and were about eight times higher. Equal doses of rufloxacin and ciprofloxacin had similar antibacterial activities. However, rufloxacin inhibitedStaphylococcus aureus bacterial growth significantly longer than did ciprofloxacin.     

The primary structure and oxygen-binding properties of the single haemoglobin of the high-Antarctic fish Aethotaxis mitopteryx DeWitt

Summary The complete amino acid sequence of the single haemoglobin of the Antarctic fish Aethotaxis mitopteryx DeWitt has been established by automated repetitive Edman degradation on the intact and cleaved (enzymatically and chemically) and chains. A very high sequence identity with other Antarctic fish haemoglobins has been detected. The haemoglobin has a moderate Bohr effect and no Root effect. Organic phosphates and chloride also regulate oxygen binding only to a moderate extent. The lack of Root effect is consistent with the substitution His — Val at the HC3 C-terminal position of the chain. The low overall heat of oxygenation suggests that in this species oxygen transport is an energy-saving process, presumably related to cold adaptation. The comparative analysis of the haemoglobins of Antarctic fishes emphasises some unique features of the oxygen-transport system of A. mitopteryx, which are likely to be related to its also rather unique mode of life.Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation     

Role of vasopressin in the modifications of renal function during aging]

In the course of aging, the renal concentrating ability is markedly reduced. This defect may result from an inappropriate synthesis of antidiuretic hormone in the central nervous system or may be due to an impaired renal response to vasopressin. The two hypotheses have been studied in vivo in rats and in vitro in mice. The results of these studies indicated that: 1) dehydration induces a comparable release of vasopressin along the hypothalamo-hypophysial axis in 10, 20 and 30 month-old rats; 2) there is no change with age of the number of nephrons, single nephron filtration rate or transport capacity of Henle's loop of cortical nephrons which could account for an impaired renal response to vasopressin; 3) the reduced concentrating ability of the kidney appears to be linked to a decreased response of the medullary thick ascending limb of Henle's loop which in part is responsible for the cortico-papillary gradient of solutes within the kidney.     

Observations on egg production rates and seasonal changes in the internal morphology of Mediterranean populations of Acartia clausi and Centropages typicus

Egg production rates in wild populations of Acartia clausi and Centropages typicus, sampled biweekly in the Gulf of Naples from October 1985 to July 1987, showed marked seasonal fluctuations with maximum values in early spring that proceeded the annual maxima for adult female densities in summer. A positive correlation between chlorophyll a concentrations and egg production was evident only during the early spring phytoplankton bloom. A strong diminution in egg deposition occurred later in spring and continued throughout the summer notwithstanding high chlorophyll concentrations. In winter, when population abundances for adult females were lowest, egg production rates were always higher than in summer. Differences in egg production rates coincided with pronounced morphological changes between summer and winter populations of both species. The most striking of these changes consisted, in winter, in the presence of a dark brown fluid-like mass of granular material that seemed to freely bathe the gonads. The presence of this substance only during periods of elevated egg production suggests that it may enhance egg production rates when the adult population reaches minimum annual levels. Such a mechanism of self-regulation may operate to dampen the effects of environmental variability thereby contributing to maintain a conservative structure in coastal copepod communities.     

Specific inhibition of human granulocyte elastase with peptide aldehydes

The kinetic features of human granulocyte elastase, chymotrypsin, porcine pancreatic elastase and elastomucoproteinase were compared. Amino acyl ester substrates were assayed and Km and kcat values were defined. Aldehyde analogues of the p-nitroanilide substrates designed for granulocyte elastase as optimal for Km appeared to be potent inhibitors. Suc-D-Phe-Pro-valinal (Ki = 40 microM) was found to inhibit granulocyte elastase competitively and specifically when measured with synthetic substrates, and the Ki was 3 microM with the natural protein substrate, elastin.     

Regulation of product synthesis in cell cultures of Catharanthus roseus (L) G. Don

Cell suspension cultures of the Madagascan Periwinkle Catharanthus roseus (L) G. Don were maintained on Gamborg's B5 medium and their growth monitored by measuring cellular fresh and dry weight, cell number and mitotic activity. Samples of cells of different ages and physiological states were subcultured onto an alkaloid production medium and their rates of growth and alkaloid accumulation measured over a period of 30–45 days. In two experiments the rate of biomass accumulation was directly related to the rate of cellular serpentine accumulation. Possible mechanisms underlying this phenomenon are discussed in relation to the properties of cells comprising the inocula.     

Molecular structure of peptaibol antibiotics: solution conformation and crystal structure of the octapeptide corresponding to the 2-9 sequence of emerimicins III and IV

The infrared absorption and 1H nuclear magnetic resonance analyses of chloroform solutions of the terminally-blocked segment corresponding to the 2-9 sequence of emerimicins III and IV, -(Aib)3-L-Val-Gly-L-Leu-(Aib)2-, are consistent with the presence of a 3(10)-helical structure of high thermal stability. The crystal structure of the octapeptide, obtained by X-ray diffraction indicates the formation of a right-handed 3(10)-helix, stabilized by six consecutive intramolecular N-H....O:C H-bonds, slightly distorted at the level of the L-Leu residue.     

Different structure of polytene chromosomes ofPhaseolus coccineus suspensors during early embryogenesis

Summary The pattern of DNA and RNA puffs in pair VII of polytene chromosomes has been investigated in the suspensor ofPhaseolus coccineus during early embryo development. The pattern of³H-TdR and³H-U incorporation has been also detected. Collected data indicate that: 1. both heterochromatic regions, p₁₁ and q_(111+112), of chromosome pair VII, organize large DNA puffs; 2. DNA puffs of both regions are specific of different embryo differentiation steps; 3. a seasonal influence on the DNA puffing seems also to be present, as demonstrated by the comparison of the results collected in two different crops; 4. the incorporation experiment by³H-TdR evidences that not all DNA puffs show clustered labeling; 5. the RNA puffing of the two regions seems also to be specific of determined embryo stages.