Effect of cooling rate on the survival of larvae, pupariation, and adult emergence of the gallfly Eurosta solidaginis

Freeze-tolerant third instar larvae of the gallfly Eurosta solidaginis were cooled at 10, 5, 1, and 0.1 degrees C min-1 to -40 degrees C and then warmed to +5 degrees C at 1 degree C min-1. After cooling and warming the larvae were transferred to 21 degrees C and the survival of larvae, success of pupariation, and adult emergence were monitored at daily intervals in comparison to an uncooled control sample. The percentage emergences of flies from larvae cooled at 10, 5, 1, and 0.1 degree C min-1 and in the control were 7, 13, 37, 77, and 67%, respectively. A number of flies in each group emerged with malformed (unextended) wings and an unretracted ptilinum on the head capsule. The percentage emergences of normal flies at the four cooling rates and from the control were 3, 0, 17, 47, and 57%. At 48 hr after exposure all larvae in each treatment were alive. First mortality was observed between 48 and 72 hr after cooling and increased with time at each cooling rate. Mortality was apportioned into four phases of development: larva, pupariation, and early and late pupae. Mortality commenced earlier at the faster cooling rates; at 10 degrees C min-1, 37% of the sample died as larvae and a further 20% failed to complete pupariation, whereas at 0.1 degree C min-1, only 3% died as larvae and 97% formed a puparium.     

Evidence for the location of OprM in the Pseudomonas aeruginosa outer membrane

Abstract OprM with a M _r of 49 K is associated with the multidrug resistance of Pseudomonas aeruginosa . Detergent fractionation of bacterial cells has demonstrated that OprM is located in the outer membrane from which it sediments with the other major outer membrane proteins. In this study we have determined the location of OprM as the P. aeruginosa outer membrane. Western immunoblots of cell fractions, obtained by sucrose density gradient centrifugation of whole cell lysates, were probed with an OprM-specific murine polyclonal antiserum.     

Synthesis of deoxynucleoside-5'-tri-3'-diphosphates by Streptomyces adephospholyticus ATP:nucleotide pyrophosphokinase

ATP: nucleotide pyrophosphokinase (EC 2.7.6.4.) of Streptomyces adephospholyticus catalyzes an efficient transfer of the 5′-β,γ-pyrophosphoryl group of dATP to the four common deoxynucleoside-5′-triphosphates at their 3′-OH positions in the alkaline pH and in the presence of Co²⁺ ions, giving the respective 3′-pyrophosphoryl derivatives. Deoxyadenosine-5′-tri-3′-diphosphate was chromatographically prepared and structurally characterized.     

Degradation of 1,2-dichlorobenzene by a Pseudomonas sp

A Pseudomonas sp. that was capable of growth on 1,2-dichlorobenzene (o-DCB) or chlorobenzene as a sole source of carbon and energy was isolated by selective enrichment from activated sludge. The initial steps involved in the degradation of o-DCB were investigated by isolation of metabolites, respirometry, and assay of enzymes in cell extracts. Extracts of o-DCB-grown cells converted radiolabeled o-DCB to 3,4-dichloro-cis-1,2-dihydroxycyclohexa-3,5-diene (o-DCB dihydrodiol). 3,4-Dichlorocatechol and o-DCB dihydrodiol accumulated in culture fluids of cells exposed to o-DCB. The results suggest that o-DCB is initially converted by a dioxygenase to a dihydrodiol, which is converted to 3,4-dichlorocatechol by an NAD+-dependent dehydrogenase. Ring cleavage of 3,4-dichlorocatechol is by a catechol 1,2-oxygenase to form 2,3-dichloro-cis,cis-muconate. Preliminary results indicate that chloride is eliminated during subsequent lactonization of the 2,3-dichloro-cis,cis-muconate, followed by hydrolysis to form 5-chloromaleylacetic acid.     

Subcellular distribution of N-ethylmaleimide-stimulatable glutathione S-transferase activity in rat liver. Evidence of localization of glutathione S-transferase in peroxisomal membrane

Subcellular distribution of glutathione S-transferase activity was investigated as stimulated form by N-ethylmaleimide in rat liver. The stimulated glutathione S-transferase activity was localized in mitochondrial and lysosomal fractions besides microsomes. Among N-ethylmaleimide-treated submitochondrial fractions, glutathione S-transferase activity was stimulated only in outer mitochondrial membrane fraction. In lysosomal fraction, it was suggested that glutathione S-transferase activity in peroxisomes, which is immunochemically related to microsomal transferase, was also stimulated, but not in lysosomes.     

Activation of human plasma prekallikrein by Pseudomonas aeruginosa elastase in vitro

Human plasma prekallikrein, precursor of the bradykinin-generating enzyme, was activated in a purified system under a near physiological condition (pH 7.8, ionic strength I = 0.14, 37 degrees C) by Pseudomonas aeruginosa elastase which is a tissue-destructive metalloproteinase. Compared with that, Pseudomonas aeruginosa alkaline proteinase poorly activated it with a rate as low as less than one-twentieth of that of elastase. The activation by elastase was blocked with a specific inhibitor of elastase, HONHCOCH(CH2C6H5)CO-Ala-Gly-NH2 (10 microM). Generation of kallikrein-like amidolytic activity was also observed in plasma deficient in Hageman factor by treatment with elastase, but was not in plasma deficient in prekallikrein. The kallikrein-like activity generated in Hageman factor deficient plasma as well as the generation process itself was indeed inhibited by anti-human prekallikrein goat antibody. These results suggest that the pathological activation of the kallikrein-kinin system might occur under certain clinical conditions in pseudomonal infections.     

Structure-activity relationships of analogs of the aphid alarm pheromone, (E)-β-farnesene

The structural components essential for activity of the aphid alarm pheromone, (E)-β-farnesene were determined through the synthesis of related farnesene and nor-farnesene analogs. Biological activity was determined with three aphid species belonging to the subfamily Aphidinae. Structural requirements determined to be important for alarm pheromone activity are: The presence of a π-bond (1.34 to 1.39 Å) adjacent to a special free rotational single bond, a (E)-configurational double bond in the central position of the molecule, and a third double bond in the terminal isoprene end of the compound.