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Biomedical subjects

D A Carlson

Publications and source records attributed to D A Carlson.

18 recordsLinked to original sources
PubMed1992

Development of specific RIA and ELISA to study trypsin modulating oostatic factor in mosquitoes.

Trypsin modulating oostatic factor (TMOF), a decapeptide (H-YDPAPPPPPP-OH) that signals the termination of trypsinlike enzyme biosynthesis in the mosquito midgut, was covalently bound to Keyhole Limpet Hemocyanin using N-hydroxysuccinimide and dicyclohexylcarbodiimide. Polyclonal antibodies raised in rabbits against this conjugate were used to develop specific RIA and enzyme linked immunosorbent assay (ELISA) to detect the peptide hormone in female Aedes aegypti. TMOF and its analogs TMOF(B) (H-DYPAPPPPPP-OH), P4 (H-YDPAPPPP-OH), P1 (H-YDPAP-OH), and poly-L-proline were tested with the antiserum. The antiserum fully recognized TMOF and partially recognized P4. Using both RIA and ELISA, we report that the amount of TMOF in the mosquito ovary is 100 +/- 20 ng (S.E.) and 96 +/- 1.4 ng (S.E.), respectively, for each assay. Minute quantities of TMOF a thousandfold lower than in the ovary were found in the mosquito brain, indicating that the hormone is probably not neural but ovarian in origin.

Aedes↗
PubMed1992

Carbon dioxide released from human skin: effect of temperature and insect repellents.

Measurement with an infrared analyzer of CO2 given off by the hands of human volunteers under laboratory conditions showed that they continuously produced CO2 at the rate of 1.0-1.8 ml/h. Increased production of CO2 was observed with increase in temperature for all subjects. Treatment of subjects with three insect repellents or ethanol resulted in a short-term drop in CO2 production, after which it returned to pretreatment levels. Olfactometer studies showed no correlation between the amount of CO2 produced by hands and the attractancy of the subjects to host-seeking female Ae. aegypti (L.). The supplemental addition of five times the amount of CO2 given off by the hands did not affect attractancy of subjects to mosquitoes. The amount of CO2 released by hands is negligible compared to ambient levels of 300 ppm, and it is unlikely to be attractive at this level of release by itself.

Animals↗
PubMed1992

In vitro assay for the biosynthesis and metabolism of juvenile hormone by exposed corpora allata of Aedes aegypti (Diptera: Culicidae).

A technique has been developed to study JH III biosynthesis in vitro by removing the head and thorax of Aedes aegypti (L.) and exposing the corpora allata (CA). Exposed CA were incubated with [12-3H]methyl farnesoate, and the newly synthesized JH III and JH III metabolites were followed using C18 reversed-phase, high-performance liquid chromatography (HPLC) and preparative gas chromatography. The rate of synthesis of [12-3H]JH III by exposed CA from newly emerged adult Ae. aegypti was 23 fmol/CA/h. The rate of synthesis of [12-3H]JH III decreased 4-fold 3 d after adult eclosion and increased to 23 fmol/CA/h 5 h after the blood meal. Exposed CA of blood-fed and sugar-fed Ae. aegypti were also incubated with L-[methyl-3H]methionine, and the rate of synthesis of JH III was studied. The rate of JH III biosynthesis increased immediately after the blood meal as was found with [12-3H]methyl farnesoate. The potential application of methyl farnesoate in monitoring the de novo synthesis of JH III in mosquitoes in vitro and in vivo is discussed.

Aedes↗
PubMed1992

Biosynthesis and metabolism of juvenile hormone III from methyl farnesoate by exposed corpora allata of Lutzomyia anthophora.

The in-vitro biosynthesis of [12-3H] juvenile hormone (JH) III by exposed corpora allata (CA) of teneral, sugar-fed, and blood-fed female Lutzomyia anthophora (Addis) was followed by incubating the CA for 4 h with [12-3H]methyl farnesoate. Synthesis of [12-3H]H III was determined by C18 reversed-phase high-pressure liquid chromatography (HPLC) and preparative gas chromatography. The rate of synthesis of JH III by teneral females was 5.6 fmol/h per CA. The CA of 1-d-old females synthesized 17 fmol/h per CA, whereas 3-d-old females synthesized 5.4 fmol/h per CA. The rate of synthesis of JH III 4 h after the blood meal increased to 17.3 fmol/h per CA and then declined to reach a minimum of 1.6 fmol/h per CA at 30 h before increasing again to reach 21.6 fmol/h per CA at 96 h. The concentration of methyl farnesoate in the tissue culture medium during incubation of CA from sugar- and blood-fed females was compared with the rate of synthesis of JH III and its metabolites diol-acid, diol, acid, and bisepoxide. The rate of synthesis of JH III and its metabolites from methyl farnesoate indicated a steady-state equilibrium of synthesis and metabolism of JH III by the exposed CA. The rapid increase in JH III synthesis immediately after the blood meal confirmed that in sand flies, like mosquitoes, there is an increase in the rate of synthesis of JH III immediately after the female takes blood. The role of the hormone in vitellogenin biosynthesis is also discussed.

Animals↗
PubMed1992

In vivo and in vitro biosynthesis and metabolism of methyl farnesoate, juvenile hormone III, and juvenile hormone III acid in the mosquito Aedes aegypti.

Biosynthesis and metabolism of juvenile hormone (JH) III in vivo and in vitro were studied in female Aedes aegypti (L.). [12-3H]Methyl farnesoate was used to follow the synthesis and [12-3H]-(10R)-JH III to study metabolism. The rate of biosynthesis of [12-3H]JH III in vivo after adult eclosion increased from 9 fmol/h per female at 1 h to 22 fmol/h per female at day 6. The rate of biosynthesis by exposed corpora allata (CA) in vitro was 23 fmol/h per CA during the 1st d after adult eclosion, then dropped to 4.8 fmol/h per CA on day 3, then increased again to a constant level of synthesis (12 fmol/h per CA) at days 4-6. Immediately after blood feeding, the rate of synthesis of [12-3H]JH III in vivo and in vitro increased to 27 fmol/h per female and to 23 fmol/h per CA, respectively. The rate of synthesis then decreased in vivo to 12 fmol/h per female at 4 h and in vitro to 6 fmol/h per CA 10 h after the blood meal. After this decrease, the rate of synthesis of [12-3H]JH III increased again reaching a peak of 25 fmol/h per female at 48-96 h in vivo and 12 fmol/h per CA at 72 h in vitro. These results indicated that the CA of sugar-fed and blood-fed female A. aegypti synthesized JH III in vivo and in vitro from [12-3H]methyl farnesoate. When [12-3H]-(10R)-JH III metabolism was followed in vivo in female A. aegypti, the ratio between JH III diol acid:JH III acid:JH III diol was 17:4:1, indicating that JH III was first hydrolyzed by JH III esterase to the acid form, then hydrated to the diol acid by JH III epoxide hydrase. Females treated with [12-3H]JH III acid converted 46% of the JH III acid in 60 min to the diol acid. These results indicated that the enzyme epoxide hydrase acted on JH III acid 17 times faster than JH III.

Aedes↗
PubMed1990

Soluble factor in normal tissues that stimulates high-molecular-weight sialoglycoprotein production by human colon carcinoma cells.

The stimulation of high molecular weight sialoglycoprotein synthesis by a soluble factor derived from normal colon tissues was studied in vitro with human colon carcinoma cell lines, HT-29 P and a metastatic variant HT-29 LMM. The synthesis of all three high-molecular-weight sialoglycoproteins (approximate Mr 900,000, 740,000, and 450,000) by HT-29 P cells or HT-29 LMM cells growing in vitro was enhanced by supplementing the culture medium with a conditioned medium of fresh human colon organ culture. Changes were detected by polyacrylamide gel electrophoresis of lysates from [3H]glucosamine-labeled cells on 3% gels followed by fluorography, or by electrophoresis of lysates from unlabeled cells followed by incubation with 125I-labeled wheat germ agglutinin and autoradiography. No changes were detected in the major protein components or in glycoproteins at Mr less than 200,000 as revealed by polyacrylamide gel electrophoresis. The treated cells did not change their growth rate or morphology. The connective tissue portions of the colon tissues were apparently responsible for the production of this stimulatory substance. The stimulatory activity was preserved at 56 degrees C but was inactivated by heating at 100 degrees C. The substance was eluted from a Sephacryl S-200 column at a position between the elution positions of ovalbumin and trypsinogen. The colon carcinoma cells treated with the conditioned medium and producing increased amounts of high-molecular-weight sialoglycoproteins were less sensitive to the cytolytic effects of recombinant interleukin 2-activated human peripheral blood lymphocytes than untreated cells were. The treated colon carcinoma cells induced stronger platelet aggregation than their untreated counterparts did. Therefore, this substance may represent one of the normal host tissue factors that can influence and modulate malignant behavior of carcinoma cells growing in vivo.

Cell Division↗
PubMed1990

Mosquito oostatic factor: a novel decapeptide modulating trypsin-like enzyme biosynthesis in the midgut.

A peptide that inhibits egg development in mosquitoes (oostatic factor) has been purified from the ovaries of female Aedes aegypti. The factor is a decapeptide with a molecular mass of 1047.6. The primary sequence has been determined as NH2-Tyr-Asp-Pro-Ala-Pro-Pro-Pro-Pro-Pro-Pro-COOH from mass spectra recorded on a quadrupole Fourier transform instrument. The amino acid sequence exhibits sequence correlation to mammalian, plant, and several viral proteins. Injection of synthetic analogs into mosquitoes, biting midges, flies, and fleas inhibited proteolytic enzyme biosynthesis in the midgut. Binding studies with [3H]oostatic factor indicated that the midgut epithelial cells have a factor-specific receptor.

Aedes↗
PubMed1990

Field studies on the potential of butanone, carbon dioxide, honey extract, 1-octen-3-ol, L-lactic acid and phenols as attractants for mosquitoes.

Various combinations of six candidate attractants--butanone, carbon dioxide (CO2), honey, octenol, lactic acid and mixed phenols--were tested against natural populations of mosquitoes in Everglades National Park, Florida, U.S.A., using unlighted CDC-baited traps. With few exceptions, the attractancy of these candidate compounds to mosquitoes, when used alone, was less than that of CO2 alone. The exceptions were that octenol and honey extract alone attracted larger numbers of Coquillettidia perturbans (Walker). Addition of lactic acid and/or octenol to CO2 increased trap collections of Aedes taeniorhynchus (Wiedemann), Anopheles atropos D. & K., and An. crucians Wiedemann by 1.4-13.8 times. Culex nigripalpus Theobald collections were increased 2.7 times by the addition of lactic acid, while the addition of octenol produced mixed results. Whereas the addition of lactic acid reduced collections of Cx (Melanoconion) spp., the addition of octenol generally increased collections. The opposite happened for Wyeomyia mitchellii (Theobald). For the biting midge, Culicoides furens (poey), octenol (1.6-23.4 x ) and phenol (2.7 x ) alone attracted larger numbers, and lactic acid alone attracted approximately the same numbers as CO2 alone. The combinations octenol + phenol and octenol + 200 ml/min CO2 increased C. furens collections c. 100 times over CO2 alone. The combination of octenol + CO2 increased (1.6 x ) collections of the tabanid Diachlorus ferrugatus (Fabricius). Butanone appeared to decrease the trap collections of all species when combined with CO2 or octenol + CO2.

Animals↗
PubMed1990

Mosquito attraction to substances from the skin of different humans.

Mosquito attraction responses to substances collected from human skin and placed on glass petri dishes were studied. Mosquito response varied according to the source of the substance. Substances removed from the head and hands elicited the greatest attraction response in laboratory-reared mosquitoes. Mosquito response lasted up to 6 h when the substance was aged and was increased by warming the samples from ca. 25 degrees C to 37 degrees C. Of the 12 mosquito species studied, attraction response was greatest in Aedes aegypti. It is cautioned that residues deposited by handling traps or other apparatus used in mosquito studies may influence test results.

Aedes↗
PubMed1979

Differentiation between species of the Anopheles gambiae Giles complex (Diptera: Culicidae) by analysis of cuticular hydrocarbons.

Lipids were extracted from 500 female Anopheles gambiae and An. arabiensis in n-hexane and the extracts examined by gas chromatographic analysis using a glass column packed with 3% OV-1 on a 100-200 mesh Gas Chrom Q which was maintained at 225 degrees C. Cuticular hydrocarbons consisted mostly of unbranched paraffins. There were differences between the distribution of compounds with 25-29 carbons. After adjusting the C27 peak to 100%, hydrocarbons C26 and C29 represent heights of 80 and 69% in An. gambiae compared with values of 49 and 95 % in An. arabiensis. Other small but consistent differences were also found. Investigations are being performed on extracts from smaller samples and on other species within the An. gambiae complex.

Animals↗
PubMed1978

Sex pheromone of the tsetse fly: isolation, identification, and synthesis of contact aphrodisiacs.

Sex pheromones isolated from the cuticle of the female tsetse fly, Glossina morsitans morsitans Westwood, release mating behavior in the male fly at ultrashort range or upon contact with baited decoys. Three active components were identified as 15,19-dimethylheptatriacontane, 17,21-dimethylheptatriacontane, and 15,19,23-trimethylheptatriacontane. Chemical and biological comparisons show that the natural and synthetic compounds are identical.

Animals↗
PubMed1977

Dream mirrors.

The mirror is not so rare a dream element as has been thought; and its appearance may mark a critical point in an analysis. Intact mirrors with clear images are reported when the dreamer has made a creative integration of previously threatening material, while mirrors that are shattered or multiplied or without reflection are accompanied by evidence of terror and a lower level of psychological organization. Study of mirror dreams can further clarify the nature of the dream screen and the role of illusion in early interactions and development.

Adult↗
PubMed1976

Mirex in the environment: its degradation to kepone and related compounds.

The chlorocarbon mirex undergoes slow, successive loss of chlorine in the field to a series of related compounds that had lost one or more chlorine atoms. Soil samples were recovered 12 years after treatment at 1 part per million (ppm), and ant bait was recovered 5 years after an aircraft crash. As much as 50 percent of the original mirex was recovered at levels of about 0.5 and 640 ppm, respectively. Kepone was present at levels of 0.02 ppm in soil and 10 ppm in the bait or up to 10 percent of the recovered mirex, as determined by combined techniques of chromatography and mass spectrometry. This constitutes the first observation of the degradation of mirex in nature, and demonstrates a pathway for its eventual disappearance from the environment.

Chlordecone↗