Extracellular and cell-bound lipase activity in relation to growth of Geotrichum candidum

Summary The imperfect fungus Geotrichum candidum produced extracellular lipase in a basic peptone-salt medium. By adding olive oil or Tween 80 to the basic medium the lipase yields could be enhanced and the maximal yields were found with Tween 80, which resulted in a sixfold increase in extracellular lipase activity as compared with basic medium. During the early phase of growth in medium with olive oil the proportion of cell-bound activity was higher than that of extracellular activity, and a delay in the secretion of extracellular lipase was found. The proportion of cell-bound activity from growth in basic medium and in basic medium with Tween 80 was lower than that of extracellular activity during the entire growth phase. Analyses by polyacrylamide gel electrophoresis showed that the lipase activity from growth in all three media could be ascribed to equivalent protein bands at 57 000 and 61 000 daltons. Immunodiffusion showed that the cell-bound preparation contained lipase that was immunologically identical with purified extracellular lipase from G. candidum.     

The cya gene region of Erwinia chrysanthemi B374: organisation and gene products

Summary A DNA fragment containing the cya gene region of Erwinia chrysanthemi, B374 was cloned in vivo and transferred into cells of E. coli using a plasmid pULB113 derived from RP4 followed by subcloning in vitro into the vector pBR322. The cya gene encodes a 95 kDal protein that complemented E. coli cya mutants. Apparently, cya genes truncated at the 3 end could still produce proteins complementing cya-defective strains, thus showing that adenylate cyclase truncated at its carboxy-terminal end could synthesise cAMP. A protein of unknown function (40 kDal) is encoded by a gene that is transcribed divergently from the control region of the adenylate cyclase gene.     

Enhanced release of oxygen metabolites by monocyte-derived macrophages exposed to proteolytic enzymes: activity of neutrophil elastase and cathepsin G

Macrophages at sites of inflammation are exposed to proteolytic enzymes derived from neutrophils, platelets, clotting factors, complement, and damaged tissues. To investigate the possible effect of proteases on the plasma membrane-mediated oxidative metabolic response of macrophages in inflammatory sites, cultured human monocyte-derived macrophages were treated in vitro with proteolytic enzymes and were then assayed for their ability to release superoxide anion (O2-) and hydrogen peroxide (H2O2) in response to stimuli. Macrophages pretreated for 1 to 20 min with trypsin, chymotrypsin, pronase, or papain, 0.1 to 200 micrograms/ml, released up to 3.5-times more O2- and H2O2 than did control (untreated) cells. This enhanced production of oxygen metabolites was observed by using either phorbol myristate acetate or opsonized zymosan as the stimulus. Macrophages were also "primed" for enhanced O2- release (2.3-fold) by pretreatment with a subfraction of granules extracted from human neutrophils. This subfraction contained primarily elastase and cathepsin G. Similar enhancement was observed with 60 ng/ml or purified human neutrophil cathepsin G (2.2-fold) and with 20 micrograms/ml of purified neutrophil elastase (3.3-fold). Priming by these neutrophil proteases could be blocked by specific inhibitors of their proteolytic activity. These results suggest that macrophages involved in an inflammatory response might be rapidly primed by proteases released from degranulating neutrophils. Primed macrophages could mount a more effective oxidative metabolic response to microorganisms or tumor cells, but might also cause greater tissue damage.     

Expression of nodule-specific uricase in soybean callus tissue is regulated by oxygen

In soybean root nodules the enzyme uricase is expressed concomitantly with nodule development. The initial expression of this protein does not depend on active nitrogen fixation, as demonstrated by analysis of uricase activity in effective and ineffective root nodules. However, the maximal level of uricase activity is determined by the infecting Rhizobium japonicum strain. Sterile root cultures and callus tissue, devoid of the microsymbiont, were incubated at varying oxygen concentrations and analyzed for uricase activity. The specific activity of uricase was increased by lowering the oxygen concentration, with the highest activity obtained around 4−5% oxygen. The increase in uricase activity was due to increased uricase synthesis, as demonstrated by in vivo labelling of callus culture followed by immunoprecipitation with antibodies raised against highly purified nodule uricase.     

Migration Inhibition Studies on Peripheral Leukocytes and Lymph Node Cells from Ruminants with Fascioliasis

Delayed type hypersensitivity against antigens of Fasciola hepatica has been repeatedly documented in infected hosts. Evidence has been presented to suggest that the delayed reactivity may develop earlier in the regional lymph nodes of the parasitized organ than in other lymph nodes of the body (Soulsby 1971).     

Characterization of 24 porcine (dA-dC)n-(dT-dG)n microsatellites: genotyping of unrelated animals from four breeds and linkage studies

Twenty-four PCR primer pairs were designed for the detection of porcine microsatellites. Polymorphism was investigated in 76 unrelated animals from four different breeds: Duroc, Landrace, Hampshire, and Yorkshire. Compared with human microsatellites, a general lower heterozygosity was detected; however, for each microsatellite a significant variation between breeds in number of alleles and heterozygosity was seen. Mean heterozygosity was found to be significantly higher (P<0.01%) in the Yorkshire breed than in the other three breeds. Linkage analyses with the CEPH linkage packet were performed in a backcross family comprising 45 animals, of which 43 had informative meioses. Ten of the microsatellites could be assigned to six different linkage groups, demonstrating that linkage mapping with microsatellites can be carried out with great efficiency in a relatively small number of animals. Four of the linkage groups represent Chromosomes (Chrs) 4, 6, 7, and 8 respectively, while two linkage groups are unassigned.The nucleotide sequence data reported in this paper have been submitted to GenBank and have been assigned the accession numbers listed in Table 1.     

Reproductive pattern,perinatal mortality,and sex preference in rural Tamil Nadu,south India: community based,cross sectional study.

OBJECTIVES: To study reproductive pattern and perinatal mortality in rural Tamil Nadu, South India. DESIGN: Community based, cross sectional questionnaire study of 30 randomly selected areas served by health subcentres. SETTING: Rural parts of Salem District, Tamil Nadu, South India. SUBJECTS: 1321 women and their offspring delivered in the 6 months before the interview. MAIN OUTCOME MEASURES: Number of pregnancies, pregnancy outcome, spacing of pregnancies, sex of offspring, perinatal and neonatal mortality rates. RESULTS: 41% of the women (535) were primiparous; 7 women (0.5%) were grand multiparous (> 6 births). The women had a mean age of 22 years and a mean of 2.3 pregnancies and 1.8 live children. The sex ratio at birth of the index children was 107 boys per 100 girls. The stillbirth rate was 13.5/1000 births, the neonatal mortality rate was 35.3/1000, and the perinatal mortality rate was 42.0/1000. Girls had an excess neonatal mortality (rate ratio 3.42%; 95% confidence interval 1.68 to 6.98; this was most pronounced among girls born to multiparous women with no living sons (rate ratio 15.48 (2.04 to 177.73) v 1.87 (0.63 to 5.58) in multiparous women with at least one son alive). CONCLUSIONS: In this rural part of Tamil Nadu, women had a controlled reproductive pattern. The excess neonatal mortality among girls constitutes about one third of the perinatal mortality rate. It seems to be linked to a preference for sons and should therefore be addressed through a holistic societal approach rather than through specific healthcare measures.     

Viomycin favours the formation of 70S ribosome couples

Summary The peptide antibiotic viomycin at a concentration of 10 M inhibits E. coli ribosomes to the extent of about 70% as measured in the poly(U) system, and to about 85% in a natural mRNA (R17) system. Ribosomes from M. smegmatis show no activity at all at this concentration of the antibiotic. Experiments on the Mg²⁺ dependent dissociation and association of the ribosomal subunits revealed that viomycin stabilizes the 70S couples and promotes association of ribosomal subunits. This response is related to the drug action as indicated by the observation that viomycin resistant strains are not affected by viomycin with respect to dissociation and 70S couple information. A model for the inhibitory action of the drug is proposed.