Shock-induced modulation of lymphocyte reactivity: suppression, habituation, and recovery

The present study was designed to evaluate the suppressive effect of different frequencies of signaled-shock presentations on mitogenic reactivity of lymphocytes in Lewis rats, and to assess the recovery of that reactivity at varying times after the shocks. The results showed that the magnitude of decreased reactivity in both the spleen and whole-blood lymphocytes, as determined by mitogenic reactivity to Concanavalin A (Con A), was directly related to the number of shock presentations within a daily session. However, the suppressed reactivity for the spleen cells diminished with repeated sessions of frequent shocks, in contrast to the whole-blood lymphocytes which did not show any habituation. Furthermore, the imposition of different periods of recovery following a single session of frequent shocks showed that the decreased reactivity for the whole-blood lymphocytes extended beyond the immediate period of the shock experience, and took 48 to 96 hours to recover completely. In contrast, the spleen lymphocytes showed complete recovery within 24 hours following the administration of shock. These results establish that the rate of habituation to and recovery from a shock-induced decrease in mitogen reactivity is more rapid for the spleen than whole-blood lymphocytes.     

Identification of the coding region for the putidaredoxin reductase gene from the plasmid of Pseudomonas putida

The first 12 NH₂-terminal amino acids of the Pseudomonas putida putidaredoxin reductase were shown to be Met-Asn-Ala-Asn-Asp-Asn-Val-Val-Ile-Val-Gly-Thr. Comparison of these data with the DNA sequence of the BamHI-HindIII 197-base fragment derived from the PstI 2.2-kb fragment obtained from the P. putida plasmid showed that the putidaredoxin reductase gene was downstream from the cytochrome P-450 gene and the intergenic region had the 24-nucleotide sequence TAAACACATGGGAGTGCGTGCTAA. The Shine-Dalgarno sequence GGAG was detected in this region. The initiating triplet for the reductase gene was GTG, which normally codes for valine, but in the initiating codon position codes for methionine. From the amino acid sequence and X-ray data comparisons with other flavoproteins, what appears to be the AMP binding region of the FAD can be recognized in the NH₂-terminal portion of the reductase involving residues 5–35.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985.     

The destruction of spores of Bacillus subtilis by the combined effects of hydrogen peroxide and ultraviolet light

Ultraviolet light irradiation of bacterial spores in the presence of hydrogen peroxide has been shown to produce synergistic kills when compared with ultraviolet light (u.v.) and hydrogen peroxide used sequentially. This use in combination has been patented for the commercial sterilization of packaging before filling with UHT-processed products. Previous results have shown that lamps producing u.v. light with a maximum output at about 254 nm were extremely effective. Results obtained using a Synchrotron radiation source to produce a narrow band of irradiation now shows that the greatest kill of spores of Bacillus subtilis in the presence of hydrogen peroxide is obtained with radiation at ˜270 nm. Such results suggest that the action of the u.v. light is not directly on the spore DNA but may be related to the production of free hydroxyl radicals from hydrogen peroxide.     

Turnover of Brain Monoamine Oxidase Measured In Vivo by Positron Emission Tomography Using l-[11C]Deprenyl

The distribution of carbon-11-labeled L-deprenyl, an irreversible inhibitor of monoamine oxidase type B (MAO-B), was determined in the baboon brain by positron emission tomography. The irreversible blood-to-brain transfer constant (influx constant, K_i) was measured using a complete metabolite-corrected arterial plasma concentration curve. This influx constant was used as a measure of functional enzyme activity for sequential determinations of MAO-B recovery following a single high dose of unlabeled l -deprenyl. The half-life for turnover of MAO-B was thus determined to be 30 days. Using appropriate irreversible inhibitors, this procedure should be generally useful for determining enzyme turnover rates in any organ in vivo and can be applied to some human studies as well.     

cDNA cloning and amino acid sequence of bovine brain 2',3'-cyclic-nucleotide 3'-phosphodiesterase

2',3'-Cyclic-nucleotide 3'-phosphodiesterase (EC 3.1.4.37) has been widely used as a marker for myelin-oligodendrocytes in the central nervous system. Evidence has been provided that the enzyme is identical with one of the Wolfgram proteins of central nervous system myelin. The amino acid sequence of bovine 2',3'-cyclic-nucleotide 3'-phosphodiesterase was determined by both protein and cDNA sequence analyses. Protein sequence analysis was done on bovine elastase 2',3'-cyclic-nucleotide 3'-phosphodiesterase, a low molecular weight enzyme obtained by solubilization with pancreatic elastase (EC 3.4.21.36) (Nishizawa, Y., Kurihara, T., and Takahashi, Y. (1980) Biochem. J. 191, 71-82; Kurihara, T., Nishizawa, Y., Takahashi, Y., and Odani, S. (1981) Biochem. J. 195, 153-157). Based on the carboxyl-terminal sequence of bovine elastase 2',3'-cyclic-nucleotide 3'-phosphodiesterase, synthetic oligodeoxyribonucleotides were prepared and used as probes for screening a cDNA library of bovine brain. A cDNA of 2305 base pairs was obtained and sequenced, and the complete amino acid sequence of bovine 2',3'-cyclic-nucleotide 3'-phosphodiesterase was deduced. Bovine 2',3'-cyclic-nucleotide 3'-phosphodiesterase deduced contains 400 amino acids including initiation methionine and has a molecular weight of 44,850. Bovine elastase 2',3'-cyclic-nucleotide 3'-phosphodiesterase corresponds to the 236 amino acids of bovine 2',3'-cyclic-nucleotide 3'-phosphodiesterase. RNA blot analysis revealed a single-species mRNA of about 2600 bases.