Dynamics of putative sex pheromone components during heat periods in estrus-induced cows.

Determination of the optimal insemination time in dairy cows is vital for fertilization success and is a challenging task due to silent or weak signs of estrus shown by some cows. This can be overcome by combining several estrus detection methods, leading to higher detection rates. However, an efficient, noninvasive method for detecting estrus in cows is still needed. Chemical cues released by the cow during estrus have been proposed to have pheromonal properties and signal readiness to mate to the bull. Such cues could be used in an industrial setting to detect cows in estrus. However, no conclusive published data show temporal changes in putative sex pheromone levels during estrus. The goal of this study was to determine the temporal pattern of putative sex pheromone components during estrus and to assess the reproducibility of changes in pheromone concentration with respect to ovulation time. Two injections of the hormone PGF2α were administered over a 2-wk interval to induce and synchronize the estrous cycles of 6 Holstein cows. The precise time of ovulation was determined by means of an ultrasound technique, and estrus was determined by visual observation. Using solid-phase microextraction gas chromatography-mass spectrometry techniques, we showed that acetic and propionic acids, which have been proposed to be putative sex pheromone components in cows, were present in the headspaces of all estrous and diestrous fecal samples, whereas 1-iodoundecane was not detected by solid-phase microextraction or by solvent extraction with diethyl ether. Low levels of acids were observed until 1 d before ovulation, at which point their concentrations increased, peaking around 0.5 d before ovulation. The application of labeled synthetic standards revealed that during the peak of release, 36 ± 8 ng (average ± SD) of acetic acid and 10 ± 3 ng of propionic acid were present in 0.5-g samples of estrous-phase fecal matter compared with 19 ± 5 and 2.3 ± 1 ng of acetic and propionic acids, respectively, in the control diestrous samples. After the peak, the amounts of the compounds decreased sharply to match those of the control samples and afterward returned to the baseline readings. This decrease in the amounts of putative pheromone components was registered about 12 h before ovulation, indicating that acetic and propionic acids could be used as biomarkers for the electronic detection of ovulation.

Methyl salicylate, identified as primary odorant of a specific receptor neuron type, inhibits oviposition by the moth Mamestra brassicae L. (Lepidoptera, noctuidae).

The cabbage moth, Mamestra brassicae L. (Lepidoptera, Noctuidae), is a polyphagous species that is often choosing plants of Brassica as hosts for oviposition. In the search for biologically relevant odorants used by these moths, gas chromatography linked to electrophysiological recordings from single receptor neurons (RNs) has been employed, resulting in classification of distinct types of neurons. This study presents specific olfactory RNs responding to methyl salicylate (MeS) as primary odorant and showing a weak response to methyl benzoate, the 2 aromatic compounds occurring together in several plant species. In 2 cases, the neuron was colocated with another RN type responding to 6 green leaf volatiles: 1-hexanol, (3Z)-hexen-1-ol, (2E)-hexen-1-ol, (3Z)-hexenyl acetate, (2Z)-hexen-1-ol, and an unidentified compound. Whereas the specific RNs detected the minor amounts of MeS in some plants, the compound was not found by gas chromatography linked to mass spectrometry in intact plants, but it was found after herbivore attack. The behavioral effect of MeS was studied in outdoor test arenas with Brassica napus and artificial plants. These experiments indicated that mated M. brassicae females avoid plants with dispensers emitting MeS. As it is induced by caterpillar feeding, this compound may mediate a message to mated M. brassicae females that the plant is already occupied.

New type of Sesiidae sex pheromone identified from the hornet moth Sesia apiformis.

Two components of the female-produced sex pheromone of the hornet moth, Sesia apiformis, were identified as (3Z,13Z)-octadeca-3,13-dien-1-ol (3Z,13Z-18:OH) and (2E,13Z)-octadeca-2,13-dienal (2E,13Z-18:Al), a pheromone structure new in Sesiidae. Pooled gland extracts showed the two major compounds in a proportion of ca. 2:3, while SPME-investigations on single calling females revealed a ratio of ca. 1:7. Although the single compounds were not attractive, a 2:3 mixture proved to be highly active towards males in field tests. Small amounts of (2E,13Z)-octadecadienol (2E,13Z-18:OH) were found in the sex pheromone gland of females, however, the biological significance of the compound remains unclear. Methyl sulfide was found to readily react with 2-alkenals, providing an effective new method for the characterization of this type of compound upon GC/MS. The derivatives, 1,1,3-tris(methylthio)alkanes, are the products of the addition of methyl sulfide to the double bond and the transformation of the carbonyl group into the corresponding bis(methylthio)acetal. The mass spectra of these compounds are characterized by diagnostic signals at m/z 107 and/or m/z 121. These fragments represent the first carbon unit or the first two carbon units of the derivative, respectively. The parent signal in the spectra of thiomethyl derivatives of 2-alkenals showing no other double bonds is represented by m/z M+ - 121, formed upon loss of the first two carbon units. By employing a solution of methyl sulfide in dimethyl sulfide, the double bond positions in 2E,13Z-18:Al could be fully characterized by GC/MS.

(-)-Germacrene D increases attraction and oviposition by the tobacco budworm moth Heliothis virescens.

The sesquiterpene germacrene D (GD) activates a major type of olfactory receptor neuron on the antennae of the heliothine moths. In Heliothis virescens females, 80% of the recordings have shown activity of one neuron type responding with high sensitivity and selectivity to GD. With the aim of determining the behavioural significance of this sesquiterpene, we have used a two-choice wind-tunnel to study the preference of mated H. virescens females for host plants with and without (-)-GD added. Tobacco plants containing dispensers with low release rate of (-)-GD had a greater attractiveness than tobacco plants without this substance. In addition, a significant increase of oviposition was found on the plants with (-)-GD.

Sex attractants for six clearwing and tineid species (Lepidoptera, Sesiidae and Tineidae) from Kazakhstan and Lithuania.

Sex attractants for 3 Sesiidae and 3 Tineidae moth species in West-Kazakhstan and Lithuania were discovered by field screening tests of (3Z,13Z)-, (3E,13Z)- and (2E,13Z)-octadecadien-1-ols and their acetates as well as of some binary mixtures of these compounds. Total amount of chemicals was 0.3 mg/dispenser. Males of Synanthedon serica were attracted by a 5:5 mixture of 3E,13Z-18:OAc and 2E,13Z-18:OAc, Chamaesphecia bibioniformis by a 9:1 mixture of 3Z,13Z-18:OAc and 3E,13Z-18:OAc, Paranthrene tabaniformis by a 1:9 mixture of 3Z,13Z-18:OH and 3E,13Z-18:OH, Tinea nonimella by a 1:9 mixture of 3E,13Z-18:OH and 2E,13Z-18:OH, Monopis monachella by a 1:9 mixture of 3Z,13Z-18:OH and 2E,13Z-18:OH, and Nemaxera betulinella by a 9:1 mixture of 2E,13Z-18:OAc and the corresponding alcohol. The periods of attraction to the traps were registered for males of S. serica and Ch. bibioniformis and were found to occur at 15-18 and 15-17 o'clock, local time, respectively.

C18 Dienes as attractants for eighteen clearwing (Sesiidae), tineid (Tineidae), and choreutid (Choreutidae) moth species.

By screening singly and binary mixed 2,13- and 3,13-octadecadien-yl acetates and alcohols (2,13- and 3,13-18: Ac/OH)in Lithuania, Armenia, Azerbaijan, Turkmenistan, Ukraine, and the far east of Russia, sex attractants were discovered for 12 Sesiidae, four Tineidae, and one Choreutidae moth species. Males ofSesia yezoensis andBembecia puella as well asNemapogon flavifrons were attracted by mixture ofZ3,Z13-18:Ac/OH in a ratio of 9∶1,Pyropteron sp. n. by the same mixture (ratio 1∶9),Bembecia romanovi andB. zuwandica byZ3,Z13-18:Ac andE3,Z13-18:Ac (9∶1),Synanthedon caucasicum by the same mixture in the opposite ratio (1∶9),B. scopigera by 23,213-18:Ac andE2,Z13-18:OH in a ratio 9∶1,Synasphecia triannuliformis byZ3,Z13-18:OH andE3,Z13-18:OH (9∶1),Similipepsis takizawai andArchimeessia sp. n. by E3,Z13-18:OH andE2,Z13-18:Ac (1∶1),Prochoreutis sechestediana by a mixture ofE3,Z13-18:Ac plusE2,Z13-18:OH (1∶),Microsphecia brosiformis by E3,Z13-18:Ac,Synanthedon conopiformis by the analogous alcohol,Synanthedon scoliaeformis andNemaxera betulinella byE2,Z13-18:Ac,Triaxomera fulvimitrella byZ3,Z13-18:Ac. An analogous alcohol component is essential for the attraction ofB. ichneumoniformis males. Inhibitors forB. romanovi, B. scopigera andB. zuwandica attraction were discovered. Preliminary data on attractants for six other species as well as on the diurnal rhythm of sexual activity of three species are presented. A new method for the stereoselective synthesis of 3,13-18:Ac/OH andE2,Z13-18:Ac/OH is described.

[Effect of cultured Polyscias cells on the activity of components of the protein-synthesizing system of rabbit liver]. / Vliianie kul'tiviruemykh kletok polistsiasa na aktivnost' komponentov beloksinteziruiushchei sistemy pecheni krolikov.

The authors studied teh effect of cultured Polyscias filcifolia Bailey cells on protein biosynthesis in an acellular system obtained from the liver of rabbits in experimental myocardial ischemia. It was found that the preparation normalizes the values of protein biosynthesis, the duration of the average polypeptide chain synthesis, and the activity of aminoacyl-tRNA synthetases.