Oral exudate as a mediator of behavior in larval eastern and western spruce budworms (Lepidoptera: Tortricidae)

The production of oral exudate by larval eastern and western spruce budworms,Choristoneura fumiferana (Clem.) andChoristoneura occidentalis Free., respectively, was investigated in the laboratory. All larvae except those entering into a molt exhibited aggressive behavior and produced exudate in response to handling or intraspecific encounters. Larvae could be induced to produce exudate up to four times over 2–3 min and produced an average of 1.92±0.04 µl (X ± SE) per induction. Larvae on foliage spent much of their time maintaining their silken feeding tunnel, including spinning and combing silk and removing frass. Exposure to conspecific oral exudate deposited inside the tunnel, or released by agitated larvae inside the tunnel, increased the proportion of larvae that dispersed away from the tunnels and, apparently, increased the larval sensitivity to disturbances. The behavior induced by the oral exudate indicates that it acts as an epideictic (spacing) pheromone.     

A conformational analysis of mono and dialkyl ethers of 2,2′-dihydroxy-1,1′-binaphthalene by circular dichroism spectroscopy and cholesteric induction in nematic liquid crystals

The coupling of the analysis of the absorption and circular dichroism (CD) spectra with that of the cholesteric mesophases induced in nematic liquid crystals indicated some interesting conformational features of bridged and nonbridged mono- and dialkylethers of optically active 2,2′-dihydroxy-1,1′-binaphthalene. Bridged derivatives are characterized by relatively small dihedral angles. Simple monoalkyl ethers are characterized by larger dihedral angles but they all assume an s-cis conformation, owing to the existence of intramolecular hydrogen bonds. Nonbridged dialkylethers prefer even larger dihedral angles and, depending on the bulkiness of the alkyl groups, the s-trans conformation can be found. Interestingly, the conformation of dialkylethers is strongly dependent on the structure of the liquid crystal solvent, because the intramolecular hydrogen bond is not possible there. © 1995 Wiley-Liss, Inc.     

Chromatographic resolution of some cyclic sulfoximides derived from prochiral and chiral sulfoxides

Three endocyclic sulfoximides of the 1-aryl- and 1-alkyl-3-oxo-benzo[d]-isothia (IV)-azole 1-oxide type (1-substituent = 2′-carboxyphenyl, 2′-carbethoxyphenyl, and octyl, respectively) were found to be well resolved on a chiral phase derived from bovine serum albumin (BSA). Selectivities (α) of 1.74, 1.12, and 1.44, respectively, were obtained. The retention behaviour of 1-octyl-3-oxo-benzo[d]isothia(IV)-azole 1-oxide was further investigated in some detail as a function of the mobile phase composition and the elution order was established from optically active material obtained from the enantiopure sulfoxide precursor. An enantiomeric excess of 85.4% was obtained in the cyclocondensation reaction of the octyl-substituted sulfoxide precursor with hydrazoic acid to the corresponding endocyclic sulfoximide. © 1995 Wiley-Liss, Inc.     

Conversion of a racemate into a single enantiomer in one step by chiral liquid chromatography: Studies with rac-2,2′-diiodobiphenyl

The enantiomers of rac-2,2′-diiodobiphenyl were separated by liquid chromatography on microcrystalline triacetylcellulose. The conformational lability, a large separation factor α, and a suitable capacity factor k′(+) of this biphenyl allowed us to convert the racemate into 90% of enantiomerically pure (-)-2,2′-diiodobiphenyl and 10% of pure (+)-2,2′-diiodobiphenyl, respectively, by a series of in situ racemization-elution cycles. The much better retained (+)-enantiomer was racemized on the chromatographic column at 50°C after the less retained (-)-enantiomer has already been eluted at 8°C. © 1995 Wiley-Liss, Inc.     

Removal of toluene in waste gases using a biological trickling filter

The removal of toluene from waste gas was studied in a trickling biofilter. A high level of water recirculation (4.7 m h^–1) was maintained in order to keep the liquid phase concentration constant and to achieve a high degree of wetting. For loads in the range from 6 to 150 g m^–3 h^–1 the maximum volumetric removal rate (elimination capacity) was 35±10 g m^–3 h^–1, corresponding to a zero order removal rate of 0.11±0.03 g m^–2 h^–1 per unit of nominal surface area. The surface removal was zero order above the liquid phase concentrations of approximately 1.0 g m^–3, corresponding to inlet gas concentrations above 0.7–0.8 g m^–3. Below this concentration the surface removal was roughly of first order. The magnitude of the first order surface removal rate constant, k_1A , was estimated to be 0.08–0.27 m h^–1 (k_1A a=24–86 h^–1). Near-equilibrium conditions existed in the gas effluent, so mass transfer from gas to liquid was obviously relatively fast compared to the biological degradation. An analytical model based on a constant liquid phase concentration through the trickling filter column predicts the effluent gas concentration and the liquid phase concentration for a first and a zero order surface removal. The experimental results were in reasonable agreement with a very simple model valid for conditions with an overall removal governed by the biological degradation and independent of the gas/liquid mass transfer. The overall liquid mass transfer coefficient, K_La, was found to be a factor 6 higher in the system with biofilm compared to the system without. The difference may be explained by: 1. Difference in the wetting of the packing material, 2. Mass transfer occurring directly from the gas phase to the biofilm, and 3. Enlarged contact area between the gas phase and the biofilm due to a rough biofilm surface.     

Identification of cellular prosomatostatin and nonsomatostatin peptides derived from its amino terminus

Rat prosomatostatin was isolated from a somatostatin-producing cell line and was partially microsequenced. This indicated the amino terminal structure of cellular prosomatostatin and implied a 92-amino acid sequence for the somatostatin precursor. Based on the structure for cellular prosomatostatin, a peptide was synthesized and used to develop a radioimmunoassay directed toward the amino terminal portion of prosomatostatin. This assay has revealed two peptides containing the amino-terminal portion of prosomatostatin in a somatostatin-secreting CA-77 rat medullary thyroid carcinoma cell line. These two peptides - MW 4000 and 8000 daltons - lack somatostatin immunoreactivity. Thus, processing of prosomatostatin occurs both at the amino and carboxyl regions. These results open the way for elucidation of the structure, function and metabolism of non-somatostatin peptides derived from the amino terminus of prosomatostatin.     

Evidence for intracellular formation of angiotensins: coexistence of renin and angiotensin-converting enzyme in Leydig cells of rat testis

Leydig cells were purified from rat testes by discontinuous metrizamide density gradient and were shown to contain renin (EC 3.4.99.1), angiotensin-converting enzyme (dipeptidyl carboxypeptidase, (EC 3.4.15.1), and the peptide hormone angiotensins I, II and III as determined by the combined HPLC and radioimmunoassay. In germinal cells only angiotensin II (AII) was found at a significant level. These findings provide evidence for intracellular formation of AII in testicular cells and demonstrate that an intracellular renin-angiotensin system exists in normal non-transformed cells.     

A chemiluminescent probe specific for singlet oxygen

We have synthesized a methoxyvinylpyrene (MVP) in order to model the mechanism for the observed microsomal chemiluminescence of benzo[a]pyrene 7,8-dihydrodiol, the proximate carcinogenic metabolite of benzo[a]pyrene. This MVP analog has been found to be a highly efficient and specific chemiluminescent probe for picomole quantities of singlet oxygen and singlet oxygen equivalents, and it produces significant chemiluminescence when reacted with cytochrome P-450 enzymes.     

Purification to apparent homogeneity of a thymocyte specific growth factor from calf thymus

A thymic peptide previously found to recruit thymocytes from G1 into S phase has been purified from a crude thymic extract by subsequent steps of gel exclusion chromatography and reverse phase high performance liquid chromatography (HPLC). The purified material, which appeared homogeneous on thin-layer chromatography and HPLC, stimulated the DNA synthesis of cultured guinea pig thymocytes in a nanomolar concentration range. The amino acid composition revealed a high content of acidic amino acids and no apparent homology to previously defined growth factors and thymus differentiation hormones.     

Selective activation of cyclic AMP dependent protein kinase by calcitonin in a calcitonin secreting lung cancer cell line

When the F1-ATPase from the thermophilic bacterium, PS3, was inactivated by 90% with 7-chloro-4-nitro[14C]benzofurazan ([14C]Nbf-Cl) at pH 7.3 and then gel-filtered, 1.25 mols of [14C]Nbf-O-Tyr and less than 0.1 mol of Nbf-N-Lys were formed per mol of enzyme. After adjusting the pH of the gel-filtered, modified enzyme to 9.0 and incubating it for 14 hrs. at 23 degrees C to promote O----N migration, 0.68 mol of Nbf-N-Lys were formed per mol of enzyme while about 16% of the original activity reappeared. Isolation of the subunits after the O----N migration showed that 90% of the incorporated 14C was present in the beta subunit, which contained 0.21 mols of [14C]Nbf-N-Lys per mol. A tryptic peptide which contained the majority of the 14C incorporated into the beta subunit was isolated and subjected to automatic amino acid sequence analysis contained 38 residues. The amino acid sequence immediately around the lysine residue labeled with [14C]Nbf-, K*, was found to be: ...I-G-L-F-G-G-A-G-V-G-K*-T-V-L-I-G... .