Identification of a Schistosoma mansoni sporocyst excretory-secretory antioxidant molecule and its effect on superoxide production by Biomphalaria glabrata hemocytes.

Excretory-secretory (E-S) products obtained during in vitro Schistosoma mansoni miracidium-to-sporocyst transformation were found to contain a 108-kDa polypeptide capable of scavenging both exogenously produced and M-line Biomphalaria glabrata hemocyte-derived superoxide (O2-) anions. Separation of crude transformation E-S products using HPLC and ion exchange chromatography resulted in the separation of two isoforms of the 108-kDa molecule. Using an in vitro phagocytosis assay, both isoforms were found to be capable of reducing O2- production by phagocytically stimulated M-line B. glabrata hemocytes without cell loss and without a concomitant reduction in phagocytosis. Although parasite antioxidant molecules appear to play a role in the evasion of host oxidative defense systems in several parasite-vertebrate systems, no previous reports of a parasite antioxidant capability against the potential of oxidative killing by invertebrate defense systems has been reported. In conjunction with the previously confirmed production of O2- by B. glabrata hemocytes and reports of reactive oxygen metabolite production by hemocytes from several molluscan species, these results indicate that reactive forms of oxygen and parasite antioxidant systems may play an important role in the determination of compatibility in the trematode-mollusc relationship.     

Isolated Bovine Spinal Motoneurons Have Specific Ganglioside Antigens Recognized by Sera from Patients with Motor Neuron Disease and Motor Neuropathy

The gangliosides GM1 and GD1b have recently been reported to be potential target antigens in human motor neuron disease (MND) or motor neuropathy. The mechanism for selective motoneuron and motor nerve impairment by the antibodies directed against these gangliosides, however, is not fully understood. We recently investigated the ganglioside composition of isolated bovine spinal motoneurons and found that the ganglioside pattern of the isolated motoneurons was extremely complex. GM1, GD1a, GD1b, and GT1b, which are major ganglioside components of CNS tissues, were only minor species in motoneurons. Among the various ganglioside species in motoneurons, several were immunoreactive to sera from patients with MND and motor neuropathy. One of these gangliosides was purified from bovine spinal cord and characterized as N-glycolylneuraminic acid-containing GM1 [GM1(NeuGc)] by compositional analysis, fast atom bombardment mass spectra, and the use of specific antibodies. Among seven sera with anti-GM1 antibody activities, five sera reacted with GM1(NeuGc) and two did not. Two other gangliosides, which were recognized by another patient's serum, appeared to be specific for motoneurons. We conclude that motoneurons contained, in addition to the known ganglioside antigens GM1 and GD1b, other specific ganglioside antigens that could be recognized by sera from patients with MND and motor neuropathy.     

Identification of a novel amino acid, o-bromo-L-phenylalanine, in egg-associated peptides that activate spermatozoa

Eight sperm-activating peptides containing a novel amino acid were isolated from the egg jelly of the sea urchin Tripneustes gratilla. Accurate mass measurement of the peptide in FAB mass spectrometry showed that the mass of the novel amino acid residue was 224.978. On the basis of the isotopic ion distribution and the degree of unsaturation, the mass value indicated that the elemental composition of the amino acid residue was C9H8O1N1Br1, suggesting that the novel amino acid was bromophenylalanine. Proton NMR spectroscopy, amino acid analysis, and RP-HPLC with three synthetic isomers of bromophenylalanine demonstrated that o-bromophenylalanine was the novel amino acid. Derivatization of the amino acid with Marfey's reagent, (1-fluoro-2,4-dinitrophen-5-yl)-L-alanine amide (FDAA), further indicated that the amino acid was the L-isomer. In other sperm-activating peptides isolated from the egg jelly of the sea urchin, both m- and p-bromophenylalanines were discovered. The presence of m-bromophenylalanine has not been previously reported in natural products, while p-bromophenylalanine is found in theonellamide F, an antifungal bicyclic peptide from a marine sponge.     

First records of two sharpnose pufferfishes from Japan

Two sharpnose pufferfishes, Canthigaster epila (Jenkins, 1903) and C. ocellicincta Allen et Randall, 1977, were collected from Okinawa-jima Island, Ryukyu Islands. One specimen each of these species was taken from relative ly deep waters: the specimen of C. epilampra caught at a depth of 60 m and that of C. ocellicincta at a depth of 40 m. These specimens represent the first records of the two species from Japan. No significant morphological differ ences were found between the present specimens and those reported from elsewhere.     

The influence of glycosylation on the fate of renin expressed in Xenopus oocytes

It has been recently reported that, in Xenopus oocytes injected with the mRNA for human renin, this secretory renal glycoprotein acquires phosphomannosyl residues on its asparagine-linked oligosaccharide chains, remains intracellular and undergoes a proteolytic cleavage which removes the prosegment. To understand the influence of glycosylation on the fate of renin in Xenopus oocytes and whether it is specific for human renin, we have expressed human renin and mouse Ren1 renin, which are glycosylated at two and three selected asparagine residues, respectively, and mouse Ren2 renin, which is not glycosylated, in Xenopus oocytes. The majority of human and Ren1 renins remained intracellular and underwent proteolytic cleavage, whereas mouse Ren2 renin was secreted efficiently. When human and Ren1 renins were expressed in oocytes treated with tunicamycin, both were secreted efficiently. A mutant of human renin, which had amino-acid substitutions at both glycosylation sites, was also secreted efficiently, whereas that mutated at one of the two sites was not. These results indicate that the majority of all of the glycosylated renin molecules remain intracellular and undergo proteolytic cleavage, probably due to the acquisition of phosphomannosyl residues, and the human renin remains intracellular if it is only glycosylated at one of the two sites.     

Utilization of vitamin A in rats with inflammation

Reductions in the concentration of retinol (vitamin A) in serum, lung and kidney were observed in rats subjected to inflammation-inducing treatments (turpentine oil injection of thermal injury). At the same time, the liver showed an almost normal vitamin A content. Feeding of retinol to vitamin A-depleted rats with inflammation revealed that intestinal absorption of retinol was still active in the inflamed state, and the livers of these rats showed good incorporation of retinol. The livers of normal and vitamin A-depleted rats subjected to the inflammatory treatments showed a normal RBP content (retinol-binding protein) and hepatic release of holo-RBP into the serum was not impaired functionally. These results suggest the possibility that the decreases of vitamin A in the lung, serum and kidney may be due primarily to enhanced local consumption of vitamin A related to the inflammation, rather than to a reduced supply of vitamin A from the liver or to decreased intestinal absorption. In bovine serum albumin (BSA)-sensitized rats produced by direct intubation of BSA into the lungs, the level of vitamin A in the lung decreased prior to that in the liver or serum, supporting the hypothesis that the decrease in vitamin A in the inflamed lungs of these rats may be due mainly to the consumption of vitamin A in the lung in response to inflammation.     

Adenosine deaminase from Azotobacter vinelandii. Purification and properties

Adenosine deaminase (EC 3.5.4.4) was found to occur in the extract of Azotobacter vinelandii, strain 0, and purified by heating at 65°C, fractionation with ammonium sulfate, DEAE-cellulose chromatography and gel filtration on Sephadex G-150. Purified adenosine deaminase was effectively stabilized by the addition of ethylene glycol. The molecular weight of the enzyme was estimated to be 66,000 by gel filtration on Sephadex G-150. The enzyme specifically attacked adenosine and 2-deoxyadenosine to the same extent, and formycin A to a lesser extent. The pH optimum of the enzyme was observed at pH 7.2. Double reciprocal plot of initial velocity versus adenosine concentration was concave upward, and Hill interaction coefficient was calculated to be 1.5, suggesting the allosteric binding of the substrate. ATP inhibited adenosine deaminase in an allosteric manner, whereas other nucleotides were without effect. The physiological significance of the enzyme was discussed in relation to salvage pathway of purine nucleotides.     

Effect of spermine on the inhibition by fatty acid on AMP deaminase reaction as a control system of the adenylate energy charge in yeast

Treatment of rats with pyrazole elevated the hepatic microsomal dimethylnitrosamine demethylase activity (DMNd) by several fold. Methylethylnitrosamine demethylase activity was also increased by pyrazole, but some classical monooxygenase activities were not induced. The treatment induced a new protein species which has an apparent molecular weight of 52,000 dal and is believed to be a cytochrome P-450 isozyme. The involvement of a hemoprotein in the pyrazole-induced DMNd was demonstrated in an experiment with CoCl₂ which decreased both the microsomal cytochrome P-450 content and DMNd. The induced enzyme with a single K_m value of 0.061 mM and V_max of 12.1 nmol/min/mg is probably the most efficient enzyme known to metabolize nitrosamines. NADPH-cytochrome P-450 reductase was also demonstrated to be an essential component enzyme of the DMNd. These results further substantiate the idea that the P-450-containing monooxygenase is responsible for the metabolism of dimethylnitrosamine in both the control and pyrazole induced microsomes.     

The role of polyamines in the regulation of AMP deaminase isozymes

The differential effects of polyamines on the activity of AMP deaminase isozyme A (from rat muscle) and isozyme B (from rat liver) are reported. Polyamines activate isozyme B but inhibit isozyme A.