The response of grass-cutting ants to natural and synthetic versions of their alarm pheromone

The responses of the grass‐cutting ants Atta bisphaerica (Forel) and Atta capiguara (Gonçalves) to the main components of their alarm pheromones were examined in simple field bioassays. Both species react most strongly to 4‐methyl‐3‐heptanone, which causes the full range of alarm behaviour and a large increase in the number of individuals near the sources. In later experiments with A. capiguara, this increase was found to be due primarily to attraction, with some arrestment also occurring. The ant response to 4‐methyl‐3‐heptanone was compared with that to crushed heads and to that with whole ants with crushed heads. The pheromone 4‐methyl‐3‐heptanone by itself stimulates the same level of attraction as crushed heads, but results in far less alarm behaviour and arrests fewer ants. Whole ants with crushed heads attract a greater number of ants than the other sources and also cause more alarm behaviour. Bodies alone attract ants, but do not result in alarm behaviour. The main component in both species is the same, supporting the view that alarm pheromones lack species specificity. However, it appears that other components may also be important either as synergists of the main compound, or by stimulating behaviours that would not be observed in its absence.     

Development of a semiochemical-based trapping method for the New Guinea sugarcane weevil, Rhabdoscelus obscurus in Guam

Abstract:  Aggregation pheromone of the Australian population of New Guinea sugarcane weevil, Rhabdoscelus obscurus (Boisduval), in conjunction with other semiochemicals, was used to develop an efficient trapping method for the weevil population in Guam. In a field experiment at Yigo, plastic bucket traps baited with the lure of the Australian R. obscurus population in combination with ethyl acetate and cut sugarcane captured significantly more weevils than traps baited with pheromone + ethyl acetate, pheromone + sugarcane or individual lure components alone. Traps baited with various semiochemical-based lures and treated with insecticide captured significantly greater numbers of weevils than those not treated with insecticide. Traps baited with cut sugarcane caught significantly more weevils than those without sugarcane. Semiochemical-based trapping in weevil management has potential either in mass trapping or as part of an integrated pest management (IPM) programme. Based on the present findings, a future line of work for the control of this weevil is proposed.     

A pungent diarylheptanoid from Alpinia oxyphylla

From the neutral fraction of the methanolic extract of the fruit of Alpinia oxyphylla, a new pungent compound has been isolated, and is shown to be 1-(4′-hydroxy-3′-methoxyphenyl)-7-phenyl-3-heptanone. This compound is 125 times more pungent than zingerone.     

(1S,3S,7R)-3-methyl-alpha-himachalene from the male sandfly Lutzomyia longipalpis (Diptera: Psychodidae) induces neurophysiological responses and attracts both males and females

Lutzomyia longipalpis adult males form leks on or near hosts and release (1S,3S,7R)-3-methyl-alpha-himachalene from their tergal glands to lure females to the same site for mating and feeding. Here we have examined whether the male-produced attractant could also serve as a male aggregation stimulus. High resolution chiral capillary gas chromatography analysis of male tergal gland extracts, synthetic (1S,3S,7R)-3-methyl-alpha-himachalene, and a synthetic mixture of all isomers of 3-methyl-alpha-himachalene, was coupled to electrophysiological recordings from ascoid sensillum receptor cells in antennae of male and female sandflies. Receptor cells of both sexes responded only to the main component of the male tergal gland extract that eluted at the same retention time as (1S,3S,7R)-3-methyl-alpha-himachalene. Furthermore, of the eight 3-methyl-alpha-himachalene isomers in the synthetic mixture only the fraction containing (1S,3S,7R)-3-methyl-alpha-himachalene, co-eluting with an isomer of (1S*,3S*,7S*)-3-methyl-alpha-himachalene, elicited an electrophysiological response from male and female ascoid sensillum receptor cells. Both males and females flew upwind in a wind tunnel towards a filter paper disk treated with either 4-6 male equivalents of the tergal gland extract, pure (1S,3S,7R)-3-methyl-alpha-himachalene or the synthetic mixture of eight isomers. This indicates that (1S,3S,7R)-3-methyl-alpha-himachalene derived from L. longipalpis males may have a dual function in causing male aggregation as well as serving as a sex pheromone for females.     

The effect of prolonged dietary administration of the non-carcinogen, 4-acetylaminofluorene on the liver of the rat. An electron microscope study

A diet containing 0.05 % of the non-carcinogen 4-acetylaminofluorene (4-AAF) was fed to male Leeds strain rats for periods of up to 10 months. Some animals were killed after 8–12 weeks, 6 months and 8–10 months of 4-AAF feeding, while further groups were returned to a normal diet after 10 months of treatment and then killed 2, 5, 9 and 12 months later. The hepatic tissues were removed and prepared for electron microscopy. The main fine structural changes induced by 4-AAF were a prominent hypertrophy of the agranular endoplasmic reticulum, glycogen depletion and lipid accumulation. It was noted that these changes persisted following withdrawal of dietary 4-AAF, for the duration of the experiment. The effects of 4-AAF are compared with those of its carcinogenic isomer, 2-acetylaminofluorene (2-AAF) and the possibility is discussed that the clear differences revealed in this study may be directly related to the relative carcinogenicities of these two compounds.     

Control of catabolism of mitochondria in oncogenesis. I. Increase of hepatic mitochondrial population during feeding inactive or marginally active amino azo dyes: absence of de novo biosynthesis

The mechanism of the well established phenomenon that the number of liver mitochondria increases during administration of 2-methyl-4-dimethylaminoazobenzene (2-Me-DAB) has been investigated. Fed to rats, both 2-Me-DAB (0.06%) and 4-diethylaminoazobenzene (4-DEAB) (0.0635 %) increase the amount of liver mitochondria by 47% and 31%, respectively. It was established that this is not due to de novo mitochondriogenesis. The increase in the amount of mitochondria correlates with an ~ 10% decrease of total liver protein per g of tissue. Mitochondrial ATP synthesis, which is a prerequisite of any anabolic situation, is drastically impaired following feeding of 2-Me-DAB beyond 1 week as indicated by a very substantial decrease of State 3 respiration, the respiratory control index, and the $\text{ADP}\text{O}$ ratio. Determination of the polysome profile and polysome/monosome ratio at intervals during 2-Me-DAB administration showed no change, despite the fact that mitochondrial components are coded for in both nuclear and mitochondrial DNA. During 4-DEAB administration there was, however, a small but definite rise of the polysome/monosome ratio. Administration of 2-Me-DAB up to 42 days brought about drastic inhibition of the incorporation of [³H]thymidine into both DNA's (approx. 59% with mitochondrial DNA and approx. 77% with nuclear DNA), indicating that these templates could not possibly be involved in the substantial increase of the mitochondrial population. The data suggest that the increase results from a steady accumulation due to increase of the half-life of mitochondria, owing possibly to an inhibition of lysosomal catabolic enzymes.     

The pheromonal activity of chiral 3-octanol for Myrmica ants

ABSTRACT. The (R)-(-)-3-octanol from the mandibular glands of Myrmica ants is the only enantiomer active as an attractant pheromone for M.scabrinodis Nyl. The S enantiomer is inactive and its presence decreases slightly the response of M.scabrinodis to the R enantiomer. (R) and (S)-2-octanol are inactive.     

Responses of male California red scale to sex pheromone isomers

The California red scale, Aonidiella aurantii (Maskell), sex pheromone components were previously identified as two independently attractive norsesquiterpenes. The four possible optical isomers of one and the four possible geometric and optical isomers of the other were synthesized and tested for male California red scale attractiveness in field tests and greenhouse bioassays. The results showed that there was enantiomeric and geometric specificity and only 1 isomer of each component was significantly more active than the others. The active isomers were (3S,6R)-3-methyl-6-isopropenyl-9 decen-1-yl acetate and (3Z,6R)-3-methyl-6-isopropenyl-3,9-decadien-1-yl acetate. The presence of other isomers, including the synthetic analogue 3-methyl-6-isopropylidene-9-decen-1-yl acetate, had no effect on trap catch.     

Storage Stability and Thermal Stability of Hordeumin,an Anthocyanin Pigment from Barley

Hordeumin stored at –40 to –80^oC in 1% HCI–methanol suffered neither from color reduction nor discoloration. After heating at 80°C for 60 min, hordeumin showed a pigment retention rate of 100%. This characteristic is because the pigment is a composite high-molecular weight compound consisting of anthocyanins and polyphenols, It was determined, however, that discoloration and browning occurred more rapidly than color reduction during storage and heating of the pigment.     

A behavioural and electrophysiological study of ovi position cues for Culex quinquefasciatus

Abstract. Both the synthetic oviposition pheromone, erythro-6-acetoxy-5-hexa-decanolide (0.01–80 μg) and a polluted water sample (0.01–80%) significantly increased oviposition by gravid female Culex quinquefasciatus Say (Diptera: Culicidae) in a laboratory assay against clean water. An additive effect resulted when 0.05 μg oviposition pheromone was combined with the polluted water dilution series. Undiluted, however, both the oviposition pheromone and the polluted water sample, alone and in combination, reduced the oviposition response to control levels. A previously reported oviposition site odour component, 3-methylindole, also significantly increased oviposition at 1 × 10^_8 to 1 × 10^-7g but at 1 × 10^_7g significantly less oviposition occurred than in control treatments. The biological activities of the compounds were additionally evaluated electrophysiologically by an EAG assay. Female mosquitoes were electrophysiologically sensitive to the oviposition cues, both pheromone and habitat-related; EAG responses of males were considerably lower than of females with 3-methylindole.     

MPTP/MPP＋诱导神经元凋亡的机制研究

1982年人们发现1-甲基-4-苯基-1,2,3,6-四氢吡啶（MPTP）能诱发PD,它的有效成分是1-甲基-4-苯基吡啶离子（MPP＋）。目前,MPTP/MPP＋广泛的被用作诱导PD实验模型的有效药物,可诱导神经元细胞发生凋亡性死亡。MPTP/MPP＋诱导细胞凋亡的机制牵涉Bcl-2、p53、caspase家族、JNK通路、ERK通路和PARP等多种机制,它们共同参与了MPTP/MPP＋诱导的细胞凋亡的调控和执行阶段。本文主要综述MPTP/MPP＋诱导的神经元细胞凋亡机制。