Influence of dietary fish on eicosanoid metabolism in man

Two groups of 40 volunteers were given a dietary supplement consisting of 135 g of mackerel or meat (control) paste per day for 6 weeks. Compliance was about 80% in both groups and the daily intake of 20:5(n-3) and 22:6(n-3) from the mackerel supplement was about 1.3 and 2.3 g, respectively. In collagen-activated platelet rich plasma, the potency of blood platelet to produce HHT from arachidonic acid (AA) clearly reduced in the mackerel group, whereas the formation of HHTE from timnodonic acid (TA) increased slightly. Changes in the formation of HHT and HHTE, measured by HPLC, correlated significantly with those of TxB2 and TxB3, respectively, measured by GC/MS. Changes in the formation of the lipoxygenase products HETE (ex AA) and HEPE (ex TA) were qualitatively similar to that seen for the cyclo-oxygenase products, but quantitatively the responses were smaller. Formation of ir TxB2 in clotting blood significantly reduced in the mackerel group. In collagen-activated, citrated whole blood, TxB2 formation tended to be reduced in the mackerel-supplemented volunteers. Mackerel consumption was associated with the formation of considerable amounts of PGI3, as judged from the appearance of 2,3-dinor-delta 17-6-keto-PGF1 alpha in urine. The amount of the major metabolite of PGI2, 2,3-dinor-6-keto-PGF1 alpha was not reduced, or even increased. The daily amount of tetranor prostaglandin metabolites in the urine did not change significantly, which indicates that mackerel supplementation did not alter the formation of prostaglandins E and F.     

Long-term survival of and plasmid stability inPseudomonas andKlebsiella species and appearance of nonculturable cells in agricultural drainage water

One year after introduction into agricultural drainage waterPseudomonas fluorescens R2f (RP4),Pseudomonas putida CYM318 (pRK2501), andKlebsiella aerogenes NCTC418 (pBR322) could be recovered on agar media. Survival of the introduced strains depended on competition with the indigenous microflora, the presence of nutrients, and the availability of air.In contrast toK. aerogenes NCTC418 (pBR322), bothPseudomonas species lost their plasmids, as indicated by the consistently lower colony counts on selective medium compared with the counts on nonselective medium. The plasmid loss did not depend on nutrient status and oxygen supply. P. fluorescens R2f cells could be detected with the immunofluorescence (IF) technique. Total cell counts determined by IF were consistently higher than corresponding colony counts. Even in samples where no colonies were recovered, R2f cells could be detected by IF. This indicated the occurrence of nonculturable R2f cells in drainage water. Homology with³²P-labelled plasmid RP4 DNA was found in several drainage water samples that originally receivedP. fluorescens R2f (RP4), by using the cell suspension filter hybridization technique. P. putida CYM318 andK. aerogenes NCTC418 cells could also be detected in sterile drainage water samples, after nonspecific staining with fluorescein isothiocyanate. Cell counts of both strains were consistently higher than corresponding plate counts.     

Hyphal and mycelial interactions betweenAgaricus bisporus andScytalidium thermophilum on agar media

The interaction betweenAgaricus bisporus andScytalidium thermophilum on agar media was studied by differential interference contrast and phase contrast microscopy.A. bisporus combatively replacesS. thermophilum in culture on agar media. The antagonistic effect ofA. bisporus is transmissible through a cellophane membrane and causes irreversible disintegration ofS. thermophilum protoplasm, resulting in a total loss of viability after prolonged interaction between the two fungi. On compost extract agar, but not on other media, the growth rate ofA. bisporus increased from 2.7 to 5.3 mm·d^–1 following contact withS. thermophilum mycelium.     

d-Ibuprofen in ocular inflammation induced by paracentesis of the rabbit eye

The anti-inflammatory compound d-ibuprofen has been investigated for anti-inflammatory and cyclooxygenase inhibitory activity in ocular inflammation induced by paracentesis of eyes of living rabbits. d-Ibuprofen is the dextro-rotary isomer of ibuprofen, a potent non-steroidal anti-inflammatory agent. Eyes pretreated topically with d-ibuprofen 0.8% showed a significant inhibition of aqueous protein (73.0%) and prostaglandin E2 (96.4%) increase after paracentesis as compared to paracentesized untreated fellow eyes and control eyes. In aqueous humor no significant correlation between the increase in prostaglandin E2 and protein could be established after paracentesis. These results indicate that d-ibuprofen could be a useful ocular anti-inflammatory agent as cyclooxygenase inhibitor.     

Structure and properties of the extracellular inulinase of Kluyveromyces marxianus CBS 6556

In the yeast Kluyveromyces marxianus two forms of inulinase were present, namely, an inulinase secreted into the culture fluid and an inulinase retained in the cell wall. Both forms were purified and analyzed by denaturing and nondenaturing polyacrylamide gel electrophoresis. With the use of endo-beta-N-acetyl-glucosaminidase H, it was established that the enzyme retained in the cell wall and the enzyme secreted into the culture fluid have similar subunits consisting of a 64-kDa polypeptide with varying amounts of carbohydrate (26 to 37% of the molecular mass). The two forms of inulinase differed in size because of their differences in subunit aggregation. The enzyme present in the culture fluid was a dimer, and the enzyme retained in the cell wall was a tetramer. The differences in oligomerization did not affect the apparent Km values towards the substrates sucrose and raffinose. These findings support the hypothesis that the retention of glycoproteins in the yeast cell wall may be caused by a permeability barrier towards larger glycoproteins. The amino-terminal end of inulinase was determined and compared with the amino terminus of the closely related invertase. The kinetic and structural evidence indicates that in yeasts two distinct beta-fructosidases exist, namely, invertase and inulinase.     

Modulation of Ganglioside Biosynthesis in Primary Cultured Neurons

Murine cerebellar cells were pulse labeled with [14C]galactose, and the incorporation of radioactivity into gangliosides and neutral glycosphingolipids was examined under different experimental conditions. In the presence of drugs affecting intracellular membrane flow, as well as at 15 degrees C, labeled GlcCer was found to accumulate in the cells, whereas the labeling of higher glycosphingolipids and gangliosides was reduced. Monensin and modulators of the cytoskeleton effectively blocked biosynthesis of the complex gangliosides GM1, GD1a, GD1b, GT1b, and GQ1b, whereas incorporation of radioactivity into neutral glycosphingolipids, such as glucosylceramide and lactosylceramide, as well as GM3, GM2, and GD3 was either increased or unaltered. As monensin has been reported to interfere with the flow of molecules from the cis to the trans stacks of the Golgi apparatus, this result highlights at least one subcompartmentalization of ganglioside biosynthesis within the Golgi system. Inhibitors of energy metabolism affected, predominantly, the biosynthesis of the b-series gangliosides, whereas a reduced temperature (15 degrees C) more effectively blocked incorporation of radiolabel into the a-series gangliosides, a result suggesting the importance of GM3, as the principal branching point, for the regulation of ganglioside biosynthesis.     

Changes in pulsatile secretion patterns of LH, FSH, progesterone, androstenedione and oestradiol in cows after superovulation with PMSG

Six heifers were injected i.m. with 2500 i.u. PMSG followed by 15 mg prostaglandin 48 h later. Serial blood samples were collected through a catheter in the caudal vena cava every 10 min for 8 h on Day 10 (7 h after PMSG administration), during luteal regression (7 h after prostaglandin administration) and on the day thereafter. Four normally cyclic heifers served as a control group. Concentrations of progesterone, androstenedione, oestradiol, LH, FSH, and PMSG in the vena cava samples were measured and the frequency and amplitudes of episodic pulses of all hormones were estimated except for PMSG. Ovaries were collected by ovariectomy at 50 h after onset of luteal regression to determine the number of preovulatory follicles (non-atretic follicles greater than or equal to 10 mm). Stimulation of follicular growth by administration of PMSG resulted in the following effects on the secretion of steroids and endogenous gonadotrophins. (1) There were no alterations in progesterone concentration and the amplitude and frequency of episodic pulses. Mean (+/- s.e.m.) concentrations were 54.1 +/- 5.8, 19.1 +/- 3.1 and 3.4 +/- 0.9 nmol/l on Day 10 (L), during luteal regression (LR) and on the day thereafter (F) respectively. (2) There were no alterations in the episodic secretion patterns of androstenedione. Mean concentrations were 0.20 +/- 0.02, 0.15 +/- 0.02 and 0.11 +/- 0.02 nmol/l for the L, LR and F periods respectively. (3) There was an increase in oestradiol concentration from 17.1 +/- 3.0 pmol/l during the L period to 233.7 +/- 86.4 pmol/l during the F period. Pulse amplitude was enhanced compared to corresponding periods in control animals whereas pulse frequency remained the same. The oestradiol concentration was significantly correlated with the number of preovulatory follicles (r = 0.82, P less than 0.05). (4) There was a suppression of the frequency of episodic LH pulses (/8 h) during the LR (3.2 +/- 0.7) and F (4.3 +/- 0.4) periods compared to corresponding periods in control heifers (9.5 +/- 0.9 and 7.0 +/- 1.5 respectively). The preovulatory LH peak occurred earlier in 4 of 6 treated heifers. (5) There was a suppression of FSH concentrations, pulse amplitude and frequency during the LR and F (17.4 +/- 0.9 mg/l, 4.7 +/- 0.8 microgram/l and 7.5 +/- 0.4 pulses/8 h) periods compared to the corresponding F-period values (35.6 +/- 6.2 mg/l, 9.8 +/- 1.6 micrograms/l and 9.3 +/- 0.3 pulses/8 h) in control heifers.(ABSTRACT TRUNCATED AT 400 WORDS)     

Rat liver microsomal progesterone metabolism: evidence for differential troleandomycin and pregnenolone 16 alpha-carbonitrile inductive effects in the cytochrome P-450 III family

The effect of Troleandomycin (TAO) and pregnenolone 16 alpha-carbonitrile (PCN) on the hepatic microsomal progesterone metabolism in the rat is evaluated. Over thirteen hydroxylated progesterone derivatives are detected, including the novel 6 beta, 21-, 6 beta, 16 alpha-, 6 beta, 16 beta- and 2,21-dihydroxy derivatives, suggesting the induction of several cytochrome P-450 isozymes. PCN treatment results overall in an augmented production of progesterone metabolites whereas TAO treatment both induces and represses specific hydroxylase activities. Progesterone metabolism with purified isozymes isolated from liver microsomes from TAO and PCN treated rats differs significantly from that observed with intact microsomes, reflecting the complexity of the induction pattern of the cytochrome P-450 III family.