Mosquito Culex Pipiens Fatigans Research Articles

A Concise Synthesis of the Natural Mosquito Oviposition Attractant Pheromone from D-Glucose

The major component of the oviposition attractant pheromone of the mosquito Culex pipiens fatigans was shown to be (-)-(5R, 6S)-6-acetoxy-5-hexadecanolide (1).1 For the chemical synthesis of this optically active pheromone,2 carbohydrates such as D-mannitol2i and 2-deoxy-D-ribose21 have been utilized as chiral templates. In this laboratory the natural pheromone has been synthesized from (S)- and (R)-O,O-isopropylideneglyceraldehyde independently, using diastereoselective dihydroxylation as the key step.2m We now describe an enantiospecific synthesis of the pheromone from D-glucose.

Inversion of configurations of contiguous carbinol centres: application to the synthesis of both enantiomers of natural products from the same enantiomerically pure starting material

A novel method for effecting the inversion of configuration of two and three contiguous carbinol centers in a diol, triol, and tetraol chain, thus affording the opposite enantiomer with ⩾98% e.e., has been developed. The method is based on the sequential formation of a terminal epoxide, Payne rearrangement, and intramolecular lactonization. Application of this methodology to the synthesis of a leukotriene A 4 intermediate and its enantiomer, and the oviposition attractant pheromone of the mosquito Culex pipiens fatigans and its enantiomer, from the same enantiomerically pure starting material is described 1.

Effects of thio-TEPA on chromosomes of Culex pipiens fatigans (=Culex quinquefasciatus Say) (Diptera: Culicidae).

In recent times, the work on genetic control of insect pests has been very much facilitated by the use of chemosterilants. The present investigation has been carried out with an aim to study the cytogenetic effects of Thio-TEPA (triethyllenethiophosphoramide and CAS No. 52-24-4) an important chemosterilant, in the brain cells of mosquito Culex pipiens fatigans. Two day old larvae were reared in 25 ppm and 5 ppm of Thio-TEPA separately. The chromosomes prepared from the brain cells of mid fourth instar larvae reveal that 25 ppm of Thio-TEPA induces chromosomal abberrations at a higher rate. The frequency of various kinds of chromosomal abnormalities were analysed, and the nature of action and damage caused by Thio-TEPA are discussed.

ChemInform Abstract: A Chiral Synthesis of a Mosquito Oviposition Pheromone.

AbstractThe enantiospecific synthesis of (+)‐(5S,6R)‐erythro‐6‐acetoxy‐5‐hexadecanolide (VII) is reported.

Asymmetric synthesis of (5R,6S)-6-acetoxy-5-hexadecanolide, the major component of the oviposition attractant pheromone of the mosquito Culex pipiens fatigans, and two of its stereoisomers

Synthese a partir de benzyloxy-2 dodecanal via l'addition de bromure de pentene-4yl magnesium

Stereoselective synthesis of the major component of a mosquito oviposition attractant pheromone from a β-lithiopropionate equivalent

β-Lithiated β-ethylthioacrylate 5 A is a versatile β-lithiopropionate equivalent. Reaction with enantiomerically pure epoxide (-)- 4 and subsequent Raney nickel treatment gives the natural oviposition attractant pheromone of the mosquito Culex pipiens fatigans (-)- 1 . From epoxide (+)- 4 the enantiomer (+)- 1 is synthesized.

Absolute configuration of mosquito oviposition attractant pheromone, 6-acetoxy-5-hexadecanolide

6-Acetoxy-5-hexadecanolide (Ia) in the oviposition attractant pheromone released from egg apical droplets of the mosquitoCulex pipiens fatigans Wied. is shown to be the (-)-(5R,6S)- enantiomer. Identification was by chromatography of the 6-trifluoroacetoxy derivatives of the natural pheromone and of the synthetic (-)-(5R,6S)- (Ib) and (+)-(5S,6R)- (IIb) enantiomers on a capillary column having a chiral stationary phase comprising a derivative of (1S,3S)-chrysanthemic acid. The synthetic (-)-(5R,6S)- enantiomer (Ia) attracted oviposition of four fold more mosquito egg rafts than the control (P < 0.01) whereas for the (5S,6R)- enantiomer (IIa) there was no statistically significant oviposition attraction.

ChemInform Abstract: ENANTIOSPECIFIC SYNTHESIS OF (+)‐ERYTHRO‐(5S,6R)‐6‐ACETOXY‐5‐HEXADECANOLIDE, AN OPTICALLY ACTIVE FORM OF THE MAJOR COMPONENT OF A MOSQUITO OVIPOSITION ATTRACTANT PHEROMONE

(+)-Erythro-(5S,6R)-6-acetoxy-5-hexadecanolide, an optically active form of the major component of an oviposition attractant pheromone of a mosquito Culex pipiens fatigans, was synthesized enantiospecifically from (+)-(R,R)-diethyl tartrate.

ENANTIOSPECIFIC SYNTHESIS OF (+)-ERYTHRO-(5S,6R)-6-ACETOXY-5-HEXADECANOLIDE, AN OPTICALLY ACTIVE FORM OF THE MAJOR COMPONENT OF A MOSQUITO OVIPOSITION ATTRACTANT PHEROMONE

Abstract (+)-Erythro-(5S,6R)-6-acetoxy-5-hexadecanolide, an optically active form of the major component of an oviposition attractant pheromone of a mosquito Culex pipiens fatigans, was synthesized enantiospecifically from (+)-(R,R)-diethyl tartrate.

Synthesis of both the enantiomers of erythro-6-acetoxy-5-hexadecanolide : The major component of a mosquito oviposition attractant pheromone

Both (5 S, 6 R)-(+)- and (5 R, 6 S)-(−)-6-acetoxy-5-hexadecanolide, the oviposition attractant pheromone of the mosquito Culex pipiens fatigans, were synthesized employing the Sharpless asymmetric epoxidation as the starting step.

ChemInform Abstract: ERYTHRO‐6‐ACETOXY‐5‐HEXADECANOLIDE, THE MAJOR COMPONENT OF A MOSQUITO OVIPOSITION ATTRACTANT PHEROMONE

AbstractAls Hauptkomponente des im Titel genannten Pheromons wird die Verbindung (I) identifiziert.

Erythro-6-Acetoxy-5-hexadecanolide, the major component of a mosquito oviposition attractant pheromone

The major component of the oviposition attractant pheromone from the apical droplet of eggs of the mosquito Culex pipiens fatigans is shown by g.l.c.–mass spectrometry, microchemical methods, and synthesis to be erythro-6-acetoxy-5-hexadecanolide (1); laboratory tests have demonstrated the activity of synthetic (1).

Loss of filarial larvae in a natural mosquito population

Analysis of log normal parasite densities of Wuchereria bancrofti in the mosquito Culex pipiens fatigans collected in the suburbs of Colombo, Sri Lanka, has shown a decreasing parasite load with age of infection. The median density of microfilarial intake in the natural population was 10.3, but this had decreased to 2.6 by the infective stage. Of the total microfilariae ingested, 51.9% were found in the thorax 12--17 hours after infection of the mosquitoes in the laboratory. Further decrease in parasite density during development could not be attributed to filarial mortality in the mosquito but could be accounted for by increasing mosquito mortality dependent on the density of parasite infection. Dissection of recently blood-fed house-resting mosquitoes gave a prevalence rate of 7% microfilarial carriers in the human population compared to a rate of 4% by routine blood-filming.

DOMINANT-AND-RECESSIVE EPISTASIS IN A HOMEOTIC MOSQUITO MUTANT

Following selection for 15 generations a pure strain of a homeotic mutant spur was isolated from a Brazilian population of the mosquito Culex pipiens fatigans. Monohybrid crosses showed a 13:3 segregation indicating dominant-and-recessive epistasis for wild-type vs. spur. This implies that a dominant allele at one locus and a recessive at the other interact to produce the mutant phenotype. Dihybrid crosses with linkage group II markers yellow and ruby gave 39:13:9:3 ratios indicating independent segregation. However, the dihybrid cross with linkage group I marker maroon showed a highly significant departure from 39:13:9:3 ratio. Data available indicate that the phenotype spur is controlled by a dominant epistat in linkage group III and a recessive epistat (approximately 31.9 crossover units from maroon) in linkage group I.

Persistence in continuous light of a circadian rhythm in the mosquito Culex pipiens fatigans Wied.

BRADY1 has discussed Truman's2 hypothesis that circadian clocks can be divided into two types: type 1 in which light seems to act directly on the oscillator, stopping it in constant light (LL); and type 2, in which the photoreceptor and oscillator are separate and the rhythm is free-running in LL. Typically, in insects, developmental events such as eclosion seem to be controlled by the first type, and daily behavioural activities by the second2. In Diptera, however, behavioural rhythms seem to be rapidly damped out by LL1; for example in the mosquito Anopheles gambiae, the ‘clock’ controlling flight activity seems to stop when the light phase is prolonged, and to restart at the next onset of darkness3, thus showing type 1 characteristics. Previously, the only known exception among the Diptera was Aedes aegypti, a light-active mosquito, in which the flight activity rhythm persists, rather weakly, in LL4. Here I show that circadian flight activity in the mosquito Culex pipiens fatigans Wied. persists in LL, although in other respects the rhythm is very similar to that in A. gambiae. As in A. gambiae3 the period of the first cycle in constant darkness (DD) is distorted by the previous light period, but, in contrast, the magnitude of the effect depends on a rhythm that evidently persists in LL.

Translocations, inversions and correlation of linkage groups to chromosomes in the mosquito Culex pipiens fatigans.

Eight sex-linked translocations and two pericentric inversions were artificially induced and isolated in the mosquito Culex pipiens fatigans. Following extensive studies on the genetics and cytology of these aberrations, correlations between the three pairs of chromosomes and the three linkage groups were established. Chromosomes 1 (shortest), 2 (longest) and 3 (intermediate) are correlated to linkage groups I, II and III respectively. These conclusions are in conflict with an earlier publication. A secondary constriction was observed on the m (but not on the M) chromosome near the centromere. Its significance is not yet clear. The genetic and cytological data indicate that the gene y may be located on the long arm and the gene ru on the short arm of chromosome 2.

Studies on phosphatases of the mosquito Culex pipiens fatigans.

Studies on phosphatases of the mosquito Culex pipiens fatigans.

Distribution and properties of phospholipase a of Culex pipiens fatigans

Phospholipase A of the mosquito Culex pipiens fatigans has been found to hydrolyze 1-acyl esters of phosphatidyl ethanolamine in the presence of deoxycholate. The enzyme had no activity toward phosphatidic acid and phosphatidyl inositol. The enzyme was present mainly in larvae with little activity in pupae or adults. The total and specific activities of the enzyme were highest in IV-instar (6-day-old) and I-instar (1-day-old) larvae, respectively. It was localized in the microsomal fraction and was distributed mainly in the abdomen and thorax of the insect. There was a striking similarity between phospholipases A and B activities in different developmental stages of the insect and in the regional and subcellular distribution of the enzymes. The enzyme was present at much higher levels in larvae of the mosquitoes Anopheles stephensi and Aedes aegypti.

Laboratory studies on radiation-induced dominant lethality in sperms in population control of the mosquito Culex pipiens fatigans Wied.

SummaryA convenient method for sterilizing the males of the mosquito is described. It is likely to meet the requirements of field application. Doses that result in 96 to 98·8 per cent sterility have no adverse effects on the males. As the ratio of sterile males to normal males is increased there is a corresponding increase in the number of sterile egg-rafts, showing that the mating competitiveness of the irradiated males is equal to the normal males.The techniques and results favour the application of the method in the field for control of the mosquito Culex pipiens fatigans.

Characterization of phospholipase B of Culex pipiens fatigans

Phospholipase B has been found in the mosquito Culex pipiens fatigans, and some of its properties have been studied. The enzyme had a high optimum temperature (45 degrees C) and broad alkaline pH optimum (8-9). It was inactive toward diacylphospholipids, and hydrolyzed lysolecithin at a higher rate than lysophosphatidyl ethanolamine. The enzyme was heat labile, but lysolecithin protected it against heat inactivation. Phosphatidyl ethanolamine, phosphatidyl choline, deoxycholate, Fe(+++), and Hg(++) inhibited the enzyme markedly. The enzyme was present mainly in larvae; little enzyme activity was detected in pupae or adults. The total and specific activities were highest in IV instar (6 day) and I instar (1st day) larvae, respectively. It was localized in the microsomal fraction and was distributed mainly in the abdomen and thorax of the insect. The enzyme was present at much higher levels of activity in larvae of the mosquitoes Anopheles stephensi and Aedes aegypti.