Effects of inhibition of nadph: cytochrome p-450 reductase on benzo(a)pyrene metabolism in mouse liver microsomes

• 1.1. Effects of antioxidants (butylated hydroxytoluene and nor-dihydroguaiaretic acid), vitamin K-related quinones (vitamin K₁ and coenzyme Q₁₀) and inorganic copper (CuSO₄), in concentrations inhibiting NADPH: cytochrome P -450 reductase, were re-examined on benzo(a)pyrene metabolism in mouse liver uninduced microsomes.
• 2.2. It was found that all these compounds decrease production of the two-electron oxygenation products of benzo(a)pyrene (monophenoles, diols) and the amounts of glucuronides in a manner parallel to their inhibitory potency against NADPH: cytochrome P-450 reductase.
• 3.3. No correlation was found between amounts of one-electron oxidation products of benzo(a)pyrene and inhibition of NADPH: cytochrome P-450 reductase.
• 4.4. Without added UDPGA the compounds studied decreased protein associated benzo(a)pyrene metabolites in parallel to the decreased overall metabolism of this polyaromatic hydrocarbon.
• 5.5. The mode of action of the studied compounds is discussed.

     

1H NMR study of metabolic alterations in the small intestine of rats infected with Hymenolepis diminuta

• 1.1. 1H NMR spectra of the duodenum, jejunum and ileum tissues of the small intestine of a rat showed metabolic gradients.
• 2.2. The concentrations of metabolites in these gut regions were altered by the presence of the tapeworm Hymenolepis diminuta.
• 3.3. In the infected duodenum there was significantly less glycogen, glucose and phosphocreatine/creatine, but significantly more lactate than in the corresponding controls.
• 4.4. Infected jejunum contained significantly less betaine but significantly more succinate, alanine and lactate.
• 5.5. Infected ileum had significantly less glycogen and taurine but significantly more alanine and lactate.

     

Effects of temperature and metabolic inhibitors on contraction of anterior byssus retractor muscle of Mytilus

• 1.1. Anterior byssus retractor muscle of Mytilus (ABRM) was stimulated to contract by ACh (acetylcholine) and effects of temperature (5–30°C), FDNB (1-fluoro 2,4 dinitro-benzene) and IAA (iodoacetic acid) on tension response were examined.
• 2.2. Isometric tension was highest at the temperature range of 10–20°C and decreased at higher and lower temperature than that range.
• 3.3. The rate of tension decay after washing of ACh was accelerated by the increase of temperature.
• 4.4. Tension redevelopment after release of 1 % during contraction was much smaller at 5°C than at 20°C.
• 5.5. Tension development by ACh and the rate of tension decay after washing of ACh were remarkably decreased by the treatment of FDNB or IAA.
• 6.6. The above results were discussed from the viewpoint that energy metabolism might be related to catch.

     

Changes of the fatty acid composition in smolts of masu salmon (Oncorhynchus masou), associated with desmoltification and sea-water transfer

• 1.1. Tissue lipid compositions of desmoltified yearlings of masu salmon (Oncorhynchus masou) obtained by keeping smoltified fish in fresh water, were examined and compared to those of smoltified fish before and after transfer to sea-water (SW).
• 2.2. Lipid contents of muscle, liver, gut and gills of desmolts tended to increase compared to those of initial smolts.
• 3.3. The increased proportion of triacylglycerol (TG) and decreased proportion of phospholipids (PL) characterized the tissue lipids of desmolts.
• 4.4. Liver and muscle lipids showed no distinct differences both in content and proportion between initial and SW smolts, but gut and gill lipids of SW smolts decreased in content accompanied by a decrease of TG and an increase of PL in proportion.
• 5.5. Excepting muscle non-polar lipids, tissue lipids of desmolts contained more mono-unsaturated fatty acids and saturated fatty acids and less polyunsaturated fatty acids (PUFA), especially (n-3) PUFA such as 22:6(n-3), than those of initial and SW smolts.
• 6.6. No large differences in fatty acid composition were seen between initial and SW smolts except for the gut.
• 7.7. The proportion of (n-3) PUFA in the gut of SW smolts was higher than that of initial smolts.
• 8.8. The results indicated that masu salmon smolts can modify their lipid metabolism to adapt to ambient salinity changes. The proportion of (n-3) PUFA particularly in polar lipids, or in osmoregulatory organs such as gut and gills, was seen to be critical in lipid types of freshwater- or sea-water-adapted fish.

     

31P-NMR study on effects of electric shock on swimming leeches,Hirudo medicinalis

• 1.1. We evaluated the effect of electric shock on swimming leeches by measuring changes in high-energy phosphate metabolism using in vivo³¹P-NMR.
• 2.2. Leeches electrically stimulated during swimming showed anodal galvanotaxis, and stopped swimming with stimulation at strong current.
• 3.3. Comparison of the concentrations of high-energy phosphate metabolites before and after electric shock using ³¹P-NMR revealed a marked decrease in β-ATP and an increase in that of Pi.
• 4.4. Electric shock apparently induces excessive muscle fatigue in leeches, resulting in transient paralysis.

     

Quantitative Early Auxin Root Proteomics Identifies GAUT10, a Galacturonosyltransferase,as a Novel Regulator of Root Meristem Maintenance

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Highlights

• •Auxin responsive proteins in Arabidopsis roots were identified from 3,514 detected proteins.
• •All six auxin receptors are stable in response to hormone via novel MRM assays.
• •The >100 differentially expressed proteins exhibit dynamic and transient responses to auxin.
• •Phenotypic screening of the top responsive proteins uncovered several novel root mutants.

     

Relative bioavailability and DNA adduct formation of benzo[a]pyrene and metabolites in the diet of the winter flounder

• 1.1. Radiolabeled metabolites of the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) were shown to be absorbed through the diet of the winter flounder, Pseudo pleuronectes americanus.
• 2.2. Oral bioavailability of a mixture of naturally produced metabolites was significantly less than that of the parent BaP.
• 3.3. Oral bioavailability of a pure metabolite, BaP-7,8-dihydrodiol (7,8-D) was found to be similar to that of BaP.
• 4.4. Both metabolites and BaP formed DNA adducts in liver.

     

Gut microflora can modify fatty acid composition in liver and egg yolk lipids of laying japanese quail (Coturnix coturnix japonica)

• 1.1. The influence of the gut microflora on lipid metabolism was investigated in germ-free (GF) and conventional (CV) laying Japanese quail.
• 2.2. Serum and egg yolk cholesterol concentrations showed comparable values in both GF and CV environments.
• 3.3. The fatty acid compostion of liver lipids was modified by the presence of gut microflora. Notably, in the presence of the gut microflora, proportion of oleic acid was reduced and conversely, stearic and linoleic acids were enhanced.
• 4.4. In egg yolk lipids, the proportion of myristoleic and palmitoleic acids was significantly lowered and that of stearic acid was significantly enhanced by the presence of the gut microflora, though the difference was very small.
• 5.5. It was suggested that oleic acid could be easily either hydrogenated to stearic acid or desaturated to linoleic acid by the action of the gut microflora in Japanese quail.

     

Characterization of the vasoactive intestinal polypeptide (VIP) in the gut of fishes

• 1.1. The presence of VIP was investigated in the dogfish, Scyliorhinus canicula, the ballanwrasse. Lubrus berggylta and the bib. Trisopterus luscus, using a specific radioreceptorassay.
• 2.2. Pure porcine VIP and gut extracts of fishes yielded similar dilution curves.
• 3.3. In the dogfish, the highest concentration of VIP was found in the hindgut. In contrast, in the two teleostei studied, the highest levels of VIP were in the first part of the gut.
• 4.4. The biologically active VIP measured by radioreceptorassay correlated well with the molecule determined using a specific radioimmunoassay.
• 5.5. Our results support the hypothesis of the appearance of VIP early in evolution.

     

Selective effect of melatonin on the proliferation of lymphoid cells

• 1.1. The present study was designed to investigate the effect of melatonin on the proliferation of normal lymphocytes and certain T-lymphomas and myelomas under in vitro conditions.
• 2.2. The results revealed that administration of 200 μM melatonin inhibited significantly the incorporation of [³H]thymidine into both normal mouse and human lymphocytes and T-lymphoblastoid cell lines.
• 3.3. On the contrary, melatonin provoked an increase of myeloma cell proliferation.
• 4.4. The influence of melatonin on hybridoma cell lines was negligible.
• 5.5. Collectively, these data demonstrated that the chief pineal indole affect selectively the processes of lymphoblastoid cell growth.

     

Cellular and intracellular localization of catalase and acid phosphatase in the midgut of Lumbricus terrestris L.: A cell fractionation study

• 1.1. Cellular and intracellular localization of catalase and acid phosphomonoesterase in the midgut of Lumbricus terrestris was studied by use of tissue fractionation.
• 2.2. At least 60–70% of the catalase resides in the chloragocyte cytosol and the remaining 30–40% resides in gut epithelium peroxisomes.
• 3.3. One of the main functions of the chloragocyte catalase is probably scavenging for H₂O₂ arising from the interaction between blood heme-protein and oxygen.
• 4.4. A simple method for the histochemical detection of cytosol catalase is proposed.
• 5.5. About 10% of the gut acid phosphatase resides in chloragocyte lysosomes. The chloragosomes contain no acid phosphatase.

     

Lipid components and utilization in consumers of a seagrass community: An indication of carbon source

• 1.1. The lipid components of three animals, the rock crab Nectocarcinus integrifons, the rock flathead Platycephalus laevigatus and the southern garfish Hyporhamphus melanochir, feeding in the seagrass beds at Corner Inlet, Victoria, Australia have been examined in detail in order to provide further information on seagrass community structure.
• 2.2. Biological marker compounds detected within animal gut content material were used to recognize dietary sources and then utilized by community members.
• 3.3. Both H. melanochir and N. integrifons have been shown to ingest and to varying degrees incorporate seagrass lipid material, thus further confirming the importance of seagrass carbon in the Corner Inlet environment.
• 4.4. The southern sea garfish H. melanochir is observed to remove C₁₈ PUFAs (polyunsaturated fatty acids) from ingested seagrass material.
• 5.5. Seagrass sterols are altered during incorporation into the lipids of this fish.
• 6.6. Lipid-rich digestive juices play a role in the digestive processes of all three animals.
• 7.7. Components tentatively identified as (NMI) (non-methylene interrupted) fatty acids have been detected in the lipids of the garfish H. melanochir and the crab N. integrifons.
• 8.8. The fecal material of all three animals represent possible sources of these lipids (NMI acids) in Corner Inlet sediments.
• 9.9. Based on lipid compositional data, N. integrifons feeds on Posidonia australis detritus and associated epiphyte material.
• 10.10. The removal of both plant and epibiota cellular lipids along the digestive tract of the crab was observed, although structural components such as long chain mono- and α,ω-dicarboxylic acids, which have been previously recognized as seagrass marker lipids are not directly absorbed.

     

Interference of benzo[a]pyrene with cytochrome P-450-mediated steroid metabolism in pyloric caeca microsomes of the sea star Asterias rubens L.

• 1.1. The effects of benzo[a]pyrene (BaP) on the metabolism of progesterone and pregnenolone, and the effects of steroids on BaP metabolism were examined in pyloric caeca microsomes of female Asterias rubens.
• 2.2. The patterns of metabolism of progesterone and pregnenolone in microsomes were similar to those found in previous studies for homogenates and tissue incubations of pyloric caeca.
• 3.3. BaP reduced the rate of hydroxylation of progesterone and pregnenolone, but had no effect on metabolite formation by non-cytochrome P-450-catalysed reactions.
• 4.4. Microsomal BaP hydroxylase activity was reduced by the presence of progesterone, but pregnenolone and testosterone had no such effect.
• 5.5. The reductions in steroid or BaP metabolism were progressive with increasing ratios of the concentration of the interfering compound to that of the assay substrate and were maximally 50% or less at ratios of × 100.
• 6.6. It is concluded that isoenzymic forms of cytochrome P-450 are present, with preferences towards either steroid or BaP metabolism. The implications of the results for the in vivo situation are discussed.

     

The effect of ovine prolactin on sodium and water transport across the intestine of the fowl (Gallus domesticus)

• 1.1. The effects of ovine prolactin on sodium and water transport across the intestine of 9-day old cockerels were studied by an in vitro everted gut sac technique and by an in vivo balance technique.
• 2.2. Prolactin was found to reduce sodium and water transport across the jejunum and the rectum. AVP was ineffective.
• 3.3. Plasma sodium levels tended to decrease in prolactin treated birds.
• 4.4. It is suggested that the action of prolactin on intestinal salt and water transport is important in maintaining electrolyte homeostasis.

     

Metabolism of benzo[a]pyrene and persistence of DNA adducts in the brown bullhead (Ictalurus nebulosus)

• 1.1. The in vitro metabolism of [³H]benzo[a]pyrene (BP) and [¹⁴C]benzo[a]pyrene-7,8-dihydrodiol (BP-7,8-diol) by liver of brown bullhead (Ictalurus nebulosus) was characterized, as was the formation and persistence of BP-DNA adducts in vivo.
• 2.2. Compared to rat liver microsomes, bullhead liver microsomes produced relatively larger amounts of BP-7,8-diol (predominantly the [−] enantiomer) and smaller amounts of BP-4,5-diol.
• 3.3. BP phase I metabolites were efficiently converted by freshly isolated bullhead hepatocytes to conjugates, predominantly glucuronides.
• 4.4. BP-7,8-diol was metabolized by hepatocytes 4-fold more rapidly than was BP and was converted to approximately equal amounts of glucuronides, glutathione conjugates and sulfates.
• 5.5. BP-DNA adducts formed in bullhead liver with a lag time of several days and maximum adduct formation at 25–30 days. The major adduct was anti-BPDE-deoxyguanosine.

     

The metabolism of testosterone by human,rabbit and rat kidney

• 1.1. The metabolism of testosterone by the homogenate, microsomal and soluble fractions of human, rabbit and rat kidneys was investigated. Human kidneys were obtained from patients who underwent surgery for cancer, and the metabolism of testosterone was investigated using the intact part and in some cases also the cancerous part.
• 2.2. Testosterone was metabolized by the homogenate and microsomal preparation of male and female human and male rat kidneys to androstenedione (4-androstene-3,17-dione) and to a lesser extent to monohydroxymonoketosteroids, dihydroxysteroids and to more polar metabolites. The main metabolites in the soluble fraction were dihydroxysteroids of the 5β-series.
• 3.3. The rabbit kidneys differed from human and rat kidneys by showing a much greater rate of testosterone metabolism and by producing epitestosterone—via androstenedione—as a major metabolite. The formation of epitestosterone was especially marked in the homogenate of rabbit kidney.

     

Organohalogen constituents of the acorn worm Ptychodera bahamensis

• 1.1. Twenty organohalogen compounds, primarily phenols, were detected in the volatile extracts of the acorn worm Ptychodera bahamensis.
• 2.2. Five chlorinated compounds, previously undescribed from acorn worms, were identified.
• 3.3. Enteropneusts can be significant contributors of halogenated organics to the marine environment.

     

The carotenoids of eggs of wild and farmed cod (Gadus morhua)

• 1.1. Eggs of wild cod, and of farmed cod fed (a) a diet supplemented with astaxanthin and (b) a diet supplemented with both astaxanthin and canthaxanthin, were analysed with respect to carotenoids.
• 2.2. The total carotenoid contents in eggs were 0.7 ppm for wild cod and 0.5 ppm for farmed cod.
• 3.3. Cod, having white flesh, deposit ketocarotenoids in the eggs, preferably astaxanthin.
• 4.4. Canthaxanthin can replace astaxanthin in the eggs, but astaxanthin appears to be deposited preferentially when both carotenoids are present in the diet.
• 5.5. The isomer distribution of (3S, 3′S):(3R, 3′S, meso):(3R, 3′R) astaxanthin in the eggs reflected the isomer composition of the diet.
• 6.6. Echinenone, 4′-hydroxyechinenone, adonixanthin and zeaxanthin encountered in cod eggs may represent reductive metabolites of canthaxanthin and astaxanthin.

     

Temperature regulation and metabolic rhythms in populations of the house sparrow,Passer domesticus

• 1.1. The house sparrow, Passer domesticus, has a circadian rhthym of metabolism and body temperature.
• 2.2. Evolutionary adaptation to a hot and humid climate is reflected in the lower metabolism and greater insulation of the Houston population than observed in populations from Ann Arbor, Michigan; Boulder, Colorado and Syracuse, New York.
• 3.3. There are no significant differences in either body temperature or evaporative water loss of all four populations.
• 4.4. The Houston population is able to survive higher ambient temperatures than is found in the Ann Arbor, Michigan or Boulder, Colorado population.