Anesthetic effects on pulmonary allergic responses in rats: changes in sensitivity to serotonin.

Subsequent to observations that pulmonary responses to antigen challenge are of different magnitudes in sensitized rats that are anesthetized with different drugs, we conducted studies to test whether the alterations in responses were due to changes in airway responsiveness to cholinergic or serotonergic challenge, opioid-receptor mediated events, or changes in mast cell mediator release. Immunoglobulin E-sensitized rats anesthetized with ketamine/urethan had larger changes in lung resistance and plasma histamine after pulmonary antigen challenge compared with rats anesthetized with fentanyl-droperidol. Blockade of opioid receptors with naloxone did not affect the responses. In unsensitized rats, airway responses to aerosolized methacholine were similar for the two anesthetics, indicating unchanged smooth muscle responsiveness; however, airway responses to intravenous serotonin were enhanced by ketamine and ablated by droperidol. We conclude that ketamine- and droperidol-induced alterations of pulmonary allergic responses are due to changes in sensitivity to serotonin and in mast cell mediator release. We speculate that mast cell mediator release may be modulated by a serotonin receptor-linked mechanism.     

Sex pheromones of the moth, Archips podana: isolation, identification and field evaluation of two synergistic geometrical isomers

By means of analytical and electroantennogram methods, cis-11-and trans-11-tetradecenyl acetate have been isolated and identified as the sex pheromones of the fruit tree tortrix moth, Archips podana. In contrast to the single compounds, mixtures in a ratio of about 1 : 1 are highly attractive to male moths in field experiments.     

Identification,purification, and characterization of pathogenesis-related proteins from virus-infected Samsun NN tobacco leaves

Ten pH-3 soluble, low-molecular-weight pathogenesis-related proteins (PRs) were found to accumulate in leaves of tobacco cv. Samsun NN reacting hypersensitively to tobacco mosaic virus. Besides the previously characterized PRs 1a, 1b, 1c and 2, these proteins were provisionally designated N, O, P, Q, R, and S in order of decreasing electrophoretic mobility in native polyacrylamide gels. Two-dimensional gel electrophoresis indicated that the PRs consist of single polypeptides, except for R, which is composed of two components with slightly different molecular weights. Estimated molecular weights in SDS-containing gels were: PRs 1a and 1b 17 kD, 1c 16.5 kD, 2 31 kD, N 33 kD, O 35 kD, P 27 kD, Q 28 kD, R 13 and 15 kD, and S 25 kD. However, based on their elution from gel filtration columns and relative moblities in native gels of different acrylamide concentrations, P and Q appeared to have molecular weights similar to those of the PR 1 group. Upon chromatofocusing no additional components were resolved. The PRs were eluted between pH 7 and 4; except for R, their pIs, as judged from isoelectric focusing, appeared to lie in the range from pH 4 to 5.2. In the presence of 6 M urea PR 1a was split into two components, one of which was strongly retarded on gels, as were P and Q. None of the PRs was detected when gels were stained for glycoproteins.By combinations of gel filtration, DEAE-cellulose chromatography, and chromatofocusing, PRs 1a, 1b, 1c, 2 and N were purified, their amino acid compositions determined, and antisera raised against each of these components. By Western blotting, antisera against either PR 1a, 1b, or 1c reacted with each of the components of the PR 1 group, as well as with PR S. Similarly, the antisera against either PR 2 or N reacted with both 2 and N, as well as with O and R. On the basis of major similarities in molecular weight characteristics, amino acid compositions, and serological relationships, it is proposed to classify tobacco PRs into five groups: 1: PRs 1a, 1b, and 1c; 2: 2a (formerly 2), 2b (N), and 2c (O); 3: 3a (P), and 3b (Q); 4: 4a and 4b (the two components of R); and 5: PR 5 (S).     

Glutamine synthetase isozymes in elasmobranch brain and liver tissues

Glutamine synthetase is present as isozymic forms in the elasmobranchs Squalus acanthias (dogfish shark) and Dasyatis sabina (stingray). Subcellular fractionation of elasmobranch brain and liver tissue shows the enzyme to be predominantly cytosolic in the former tissue and mitochondrial in the latter. For the cytosolic brain enzyme, the subunit Mr equals 42,000 in the stingray and 45,000 in the shark, as determined by sodium dodecyl sulfate-gel electrophoresis/Western blotting. The subunit Mr = 45,000 and 47,000, respectively, for stingray and dogfish mitochondrial liver enzymes. Translation of total brain RNA from both species gives immunoprecipitable nascent peptides of the same size as their respective mature enzymes. However, in liver tissue, translation of glutamine synthetase mRNA yields peptides of higher Mr than that of the mature enzymes. In dogfish liver, Mr = 50,000 for the translation product and, in stingray liver, Mr = 48,000. This suggests that the translocation of the enzyme into liver mitochondria may be via a signal or leader sequence mechanism. The larger liver isozyme of elasmobranch glutamine synthetase is found in kidney where it is also known to be mitochondrial. The smaller cytosolic isozyme occurs in retina, heart, gill, and rectal gland tissue as well as in brain.     

Cigarette smoking: profiles of thromboxane- and prostacyclin-derived products in human urine

Thromboxane (TX) B2, 2,3-dinor-TXB2, 11-dehydro-TXB2, 6-oxoprostaglandin (PG)F1 alpha and 2,3-dinor-6-oxo-PGF1 alpha were measured in 24 h urine samples obtained from 30 apparently healthy chronic cigarette smokers and 37 closely matched non-smoking control subjects. Samples were analysed using a newly developed assay based on immunoaffinity chromatography and capillary column gas chromatography/electron capture negative ion chemical ionisation mass spectrometry. There were significant and comparable increases in the excretion rates of both 2,3-dinor-TXB2 and 11-dehydro-TXB2 in the smoking compared with the non-smoking group (2P less than 0.001). Excretion rates of 2,3-dinor-TXB2 were 418 +/- 35 and 265 +/- 26 pg/mg creatinine in the two groups, respectively. 11-Dehydro-TXB2 excretion rates were 440 +/- 54 and 221 +/- 18 pg/mg creatinine, respectively (mean +/- S.E.). There were significant (2P less than 0.05) positive correlations between average reported cigarette consumption and excretion of both thromboxane metabolites. There were small but significant (2P less than 0.02) increases in the excretion rates of both 6-oxo-PGF1 alpha and 2,3-dinor-6-oxo-PGF1 alpha in the smoking compared with the non-smoking group. There was no significant difference in the rates of excretion of TXB2 in the two groups. The effects of acute cigarette smoke exposure (five cigarettes in 2 h) was also studied in four normally non-smoking healthy volunteers. There was no significant change in the excretion rate of any of the eicosanoids measured during control and smoking periods (at least 2 weeks apart), indicating that increased TXA2 biosynthesis in chronic smokers is unlikely to be a consequence of acute platelet activation.     

Models of proteolysis of oligomeric enzymes and their applications to the trypsinolysis of citrate synthases.

A simple statistical approach was used to generate predictive models of the proteolysis of multisubunit enzymes in order to correlate the loss of enzyme activity with the loss of native subunit. The models were applied to the trypsinolysis of the citrate synthases of pig heart, Bacillus megaterium and Escherichia coli. With the dimeric citrate synthases (pig heart and B. megaterium) trypsinolysis of one of the subunits appears to destroy the activity of the whole enzymic molecule. The hexameric E. coli citrate synthase behaves like a trimer of dimeric units, each of the dimers behaving similarly to the B. megaterium and pig heart enzymes. Palmitoyl-CoA is required for the trypsinolysis of pig heart citrate synthase, and at relatively high concentrations of this compound trypsinolysis of one subunit leaves the other subunit fully active. Palmitoyl-CoA is not required for the trypsinolysis of the other citrate synthases, and high concentrations of this metabolite do not affect the correlation of proteolysis with inactivation of these enzymes.     

RFLP maps of potato and their alignment with the homoeologous tomato genome

Summary An RFLP linkage map of the potato is presented which comprises 304 loci derived from 230 DNA probes and one morphological marker (tuber skin color). The self-incompatibility locus of potato was mapped to chromosome I, which is homoeologous to tomato chromosome I. By mapping chromosome-specific tomato RFLP markers in potato and, vice versa, potato markers in tomato, the different potato and tomato RFLP maps were aligned to each other and the similarity of the potato and tomato genome was confirmed. The numbers given to the 12 potato chromosomes are now in accordance with the established tomato nomenclature. Comparisons between potato RFLP maps derived from different genetic backgrounds revealed conservation of marker order but differences in chromosome and total map length. In particular, significant reduction of map length was observed in interspecific compared to intraspecific crosses. The distribution of regions with distorted segregation ratios in the genome was analyzed for four potato parents. The most prominent distortion of recombination was found to be caused by the self-incompatibility locus.     

Differential expression and localization of brain-type and mitochondrial creatine kinase isoenzymes during development of the chicken retina: Mi-CK as a marker for differentiation of photoreceptor cells

The expression and the cellular- as well as subcellular-distribution of brain-type B-CK and mitochondrial Mi-CK during development of the chicken retina was studied by immunoblotting, immunofluorescence and immunogold methods. B-CK expression and accumulation in retina was high from early stages of embryonic development on, decreased slightly around hatching and remained high again during adulthood. At early stages of development (days 2-5), B-CK was more or less evenly distributed over the entire retina with the exception of ganglion cells, which were stained more strongly for B-CK than other retinal precursor cells. Then, at around day 10, the beginning of stratified immunostaining by anti-B-CK antibody was noted concomitant with progressing differentiation. Finally, a dramatic increase in staining of the differentiating photoreceptor cells was seen before hatching (day 18) with weaker staining of other cell types. At hatching, as in the adult state, most of the B-CK was localized within rods and cones. Thus, during retinal development marked changes in the immunostaining pattern for B-CK were evident. By contrast, Mi-CK expression was low during development in ovo and rose just before hatching with a predominant accumulation of this isoenzyme within the ellipsoid portion of the inner photoreceptor cell segments. Mi-CK accumulation in the retina coincided with functional maturation of photoreceptors and therefore represents a good marker for terminal differentiation of these cells. B-CK, present from early stages of retina development, seems to be relevant for the energetics of retinal cell proliferation, migration and differentiation, whereas the simultaneous expression of both B- and Mi-CK around the time of hatching indicates a coordinated function of the two CK isoforms as constituents of a PCr-circuit involved in the energetics of vision, which, in autophagous birds, has to be operational at this point in time.