Comparative Growth of Natural Bacterial Isolates on Various Lignin-Related Compounds

Bacterial strains were isolated on the basis of their ability to proliferate in a minimal medium containing one of a series of lignin-related compounds as the sole carbon and energy source. These included the aromatic monomers guaiacol, vanillic and coumaric acids, a dimer and a trimer possessing the arylglycerol-β-aryl ether linkage, anisoin, and both the ether-soluble and -insoluble fractions of kraft lignin. The growth of the strains on each of these compounds was measured. The results showed that the metabolic properties of the strains varied according to the structure of the carbon sources used for their selection. Spectrophotometric tracings of the culture medium during the log phase of growth of one of the strains on the β-O-4 dimer revealed decomposition with the release of guaiacol.     

Human thermoregulatory responses to cold air are altered by repeated cold water immersion

The effects of repeated cold water immersion on thermoregulatory responses to cold air were studied in seven males. A cold air stress test (CAST) was performed before and after completion of an acclimation program consisting of daily 90-min cold (18 degrees C) water immersion, repeated 5 times/wk for 5 consecutive wk. The CAST consisted of resting 30 min in a comfortable [24 degrees C, 30% relative humidity (rh)] environment followed by 90 min in cold (5 degrees C, 30% rh) air. Pre- and postacclimation, metabolism (M) increased (P less than 0.01) by 85% during the first 10 min of CAST and thereafter rose slowly. After acclimation, M was lower (P less than 0.02) at 10 min of CAST compared with before, but by 30 min M was the same. Therefore, shivering onset may have been delayed following acclimation. After acclimation, rectal temperature (Tre) was lower (P less than 0.01) before and during CAST, and the drop in Tre during CAST was greater (P less than 0.01) than before. Mean weighted skin temperature (Tsk) was lower (P less than 0.01) following acclimation than before, and acclimation resulted in a larger (P less than 0.02) Tre-to-Tsk gradient. Plasma norepinephrine increased during both CAST (P less than 0.002), but the increase was larger (P less than 0.004) following acclimation. These findings suggest that repeated cold water immersion stimulates development of true cold acclimation in humans as opposed to habituation. The cold acclimation produced appears to be of the insulative type.     

Beta-endorphin/beta-lipotropin release and gonadotropin secretion after acute exercise in normal males

The plasma beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) response to acute exercise and the relationship of these opioid peptides to basal and luteinizing hormone-releasing hormone (LRH)-stimulated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion was studied in eight normal male volunteers. Acute exercise resulted in a rise in plasma beta-LPH levels that returned to base line when measured 60 min after exercise. Plasma beta-EP levels did not demonstrate any rise when measured immediately after 20 min of exercise or at 60 min after exercise. Serum LH concentrations in individual volunteers declined to nadir values 60-180 min after exercise after which they showed a rebound to levels higher than the preexercise values in three of five volunteers in whom nadir LH levels were attained before the final (180 min) measurement. Serum FSH concentrations were unaltered by exercise. Acute exercise similarly did not alter the LH/FSH response to exogenous LRH stimulation. Pretreatment of the volunteers with the narcotic antagonist, naloxone, failed to alter the postexercise or LRH-stimulated LH and FSH release. The data suggest that beta-EP does not exert a suppressive effect on LH secretion after acute exercise in normal human males. Whether the suppression of LH secretion after acute exercise in unconditioned males is due to factor(s) cosecreted with beta-LPH, an increase in brain beta-EP or to alternate mechanisms such as alteration in central dopaminergic or GABAergic tone remains to be established.     

Differential interleukin 1 elaboration by unfractionated and density fractionated human alveolar macrophages and blood monocytes: relationship to cell maturity

The elaboration of interleukin 1 (IL 1) by mononuclear phagocytes is important in the regulation of human inflammatory and fibrotic reactions. Mononuclear phagocytes are morphologically and functionally heterogeneous cells. To further understand the processes controlling inflammation and fibrosis, in particular that in the human lung, we studied the elaboration of IL 1 by unfractionated and density-fractionated human alveolar macrophages and blood monocytes. Stimulated blood monocytes elaborated more IL 1 than stimulated alveolar macrophages. In addition, denser alveolar macrophages and blood monocytes elaborated more IL 1 than less dense alveolar macrophages and monocytes. Lastly, as monocytes matured in vitro, they lost their ability to elaborate IL 1 and became less dense. Thus, there is variability between and within mononuclear phagocyte cell populations in their ability to elaborate IL 1. These differences may result in part from differences in cell maturation.     

Genotoxicity studies with mineral oils; effects of oils on the microbial mutagenicity of precursor mutagens and genotoxic metabolites

In vitro genotoxicity assays are extensively used to predict carcinogenic activity in vivo. The standard microbial mutagenicity assays however often fail to yield positive results with mineral oils which are carcinogenic to mice in long-term skin-cancer studies. A comprehensive programme of studies has therefore investigated the basis of this apparently anomalous behaviour. This investigation has addressed the possible effects of oils on the bioactivation of precursor mutagens and the disposition of mutagenic metabolites by studying the microbial mutagenicity of selected precursor mutagens (benzo[a]pyrene, benzo[a]anthracene, 2-aminoanthracene and 2-naphthylamine) and intrinsically reactive mutagens [+/- )-benzo[a]pyrene-4,5-oxide and (+/-)-7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene) in the presence and absence of mineral oils. Notably the mutagenicity associated with the deliberate additions of these mutagens or precursor mutagens to oils was readily detected by the microbial assays. The mutagenicity of only one of the precursor mutagens, benzo[a]pyrene, was significantly reduced by the oils, and then only in the standard plate-incorporation assay. Interestingly the degree of suppression appeared to be related to the polycyclic aromatic hydrocarbon content of the oils. In the case of 2-aminoanthracene large enhancements in its mutagenicity were observed in the presence of oils. These latter findings appear to be due to effects of oils on the bioactivation of precursor mutagens rather than on the disposition of their bioactivation products. The mutagenicity of intrinsically reactive mutagens, of a type generated by bioactivation of polycyclic aromatic hydrocarbons, was not significantly reduced in the presence of mineral oils. This indicates that it is unlikely that components in oils trap or facilitate the deactivation of ultimate mutagens whether these pre-exist in the oil or are formed from precursors by bioactivation in the in vitro test system. Viewed overall these results suggest that mineral oils judged to be carcinogenic on the basis of in vivo studies in mouse skin may possess only very weak genotoxic potential. While this potential is likely to be a prerequisite for carcinogenic action, the current results cause attention to be focussed on other factors, e.g. promotion, as potentially important determinants of the carcinogenic potencies of mineral oils in mouse skin.     

Induction of oestrus in the camel (Camelus dromedarius) during seasonal anoestrus

Injection of 7000 i.u. PMSG induced oestrus in 7 camels during the last part of seasonal anoestrus. Mature follicles developed and a CL was formed after fertile mating. However, pregnancy was not maintained by Day 60 in the 3 females detected as pregnant by rectal palpation and increased progesterone concentrations at Day 50. A single male camel mated with 4 of the females 2-16 days after the PMSG injection, and 2 or 3 matings occurred. The failure of pregnancy after induction of oestrus and mating during seasonal anoestrus was probably due to inadequate luteal function.     

Management of a harem breeding colony of rhesus monkeys to reduce trauma-related morbidity and mortality

A management procedure was developed for a harem breeding colony of rhesus monkeys to reduce trauma-related injuries and deaths resulting from the periodic removal of pregnant monkeys for research and their subsequent return to the population. Lower morbidity and mortality rates, a reduced mean conception interval, and a higher mean conception rate occurred when monkeys were maintained in permanent harems to which returning females were reintroduced compared to new social groups formed from aggregates of unfamiliar animals.     

Cloning and characterization of DNA complementary to rat liver UDP-glucuronosyltransferase mRNA

UDP-glucuronosyltransferase (transferase) clones were isolated from a cDNA bank constructed in pBR322 using transferase-enriched mRNA from the livers of phenobarbital-treated rats. The enrichment of mRNA was accomplished by polysome immunoadsorption with antibody to purified mouse liver transferase. This antibody was shown to bind specifically to rat transferase by Ouchterlony double diffusion analysis, immunoadsorption of glucuronidating activities, and selective inhibition of the immunoadsorption of in vitro synthesized enzyme by purified rat liver transferase. The isolated clones were verified to contain DNA complementary to transferase mRNA by hybrid translation-selection. Three classes of transferase cDNAs were characterized by restriction endonuclease mapping, and the largest insert-containing clone of each class was designated pUDPGTr-1, pUDPGTr-2, and pUDPGTr-3. Their insert sizes were approximately 2,400, 2,000, and 2,000 bp, respectively. All three cDNAs hybridized with a 2,300 +/- 150 bp mRNA, and each selected the translation of a 52,000-dalton polypeptide. Immunoadsorption of the 35S-labeled translation product could be competitively inhibited in each case by the addition of purified rat liver transferase. pUDPGTr-1 and pUDPGTr-3 inserts shared extensive sequence homology. This was demonstrated by Southern blot analysis using purified inserts and electron microscopic heteroduplex analysis. Southern blot analysis revealed that these cDNAs hybridized to overlapping genomic fragments. pUDPGTr-2 shared less sequence homology with the other two classes of cDNAs, based on the above criteria. In addition, mRNA corresponding to pUDPGTr-2 was elevated 5-fold by phenobarbital treatment, whereas the other mRNAs levels were unaffected. These studies demonstrate that in rat liver there are a minimum of three distinct transferase mRNAs, two of which may be associated with a common gene or gene family.