Partial characterization and HPLC isolation of bacteria-produced attractants for the Mexican fruit fly,Anastrepha ludens

Methods were developed to collect and isolate volatile chemicals produced by aStaphylococcus bacterium in tryptic soy culture that are attractive to protein-hungry adult Mexican fruit flies. Centrifugation of bacteria culture yielded a slightly attractive pellet containing most of the bacteria cells and a highly attractive supernatant. Supernatant filtered to remove the remaining bacteria was as attractive as the unfiltered supernatant. Filtrate at pH 7 and above was much more attractive than filtrate at pH 5 and below. Most of the attractiveness was retained on strong cation exchange media under acidic conditions and eluted with base. Attractive principles could not be trapped on adsorbents such as Porapak Q or extracted with organic solvents from aqueous preparations, but they were easily collected by headspace sweeping with steam. The attractive components were efficiently concentrated by rotary evaporation of steam distillate at pH 5, but at higher pH much of the attractiveness distilled. A reverse-phase HPLC method using a negative counter-ion was developed to separate and collect attractive components of concentrated steam distillate. Attractive fractions collected using this method were concentrated and injected onto silica HPLC. Activity eluted from silica in two distinct bands. Results suggest that the most attractive components of the bacterial odor are highly polar, low-molecular-weight amines.Diptera: Tephritidae.     

Analysis of field-weathered lures containing (E)-10-dodecen-1-yl acetate,a sex attractant for the pea moth,Cydia nigricana (F.)

Natural rubber stoppers treated with 1, 3, or 10 mg of (E)-10-dodecen-1-yl acetate, an attractant for male pea moth,Cydia nigricana (F.), were exposed in the field during the summer of 1978 and samples analyzed at intervals. The results for all three doses fitted well to first-order loss curves with half-lives of 63.5, 64.7, and 67.3 days, respectively. Thus, lures with an initial dose of 3 mg of the attractant retained approximately 1 mg after 3 months of field exposure; they should therefore maintain a constant level of attractiveness throughout this period because previous field studies showed that moths were equally responsive to fresh lures containing between 1 and 10 mg of the attractant. There was no loss of attractant during the preparation of lures or after 4 months at –15 ° C and only 13% was lost during 3 months of storage at room temperature.     

Field Response of Southern Pine Beetle Parasitoids to Some Natural Attractants

Studies were performed to isolate and identify semiochemicals that mediate location of host-infested trees by parasitoids of the southern pine beetle (SPB), Dendroctonus frontalis. Bark or bolts removed from pines infested with SPB broods attracted significant numbers of the hymenopterous parasitoids Spathius pallidus and Roptrocerus xylophagorum to sticky traps placed in an active SPB infestation. Traps baited with the water distillate of SPB brood-infested bark also attracted both species of parasitoids. In contrast, a synthetic bait composed of 18 compounds identified from the headspace volatiles of attractive bark failed to trap parasitoids. The oxygenated and hydrocarbon components of the bark distillate were partitioned by silica gel liquid chromatography, and the resulting two fractions were tested in the field. Parasitoid attraction was greatest when both fractions were released from traps simultaneously. The hydrocarbon fraction, which failed to attract parasitoids, enhanced the weak attractiveness of the oxygenated fraction. Hence, it appears that no single compound is responsible for mediating SPB parasitoid host-tree location and that both oxygenated and hydrocarbon semiochemicals are involved in this process.     

Attraction responses of the American cockroach to synthetic periplanone-B

Synthetic periplanone-B has been shown not only to be a sex excitant to malePeriplaneta americana by bioassay in the laboratory but also an attractant pheromone by field tests in a rice storage house in Taipei. During both summer and winter months, it attracted signincantly more adult males into the traps used in the experiments than adult females. There is a statistically significant increase in the sex ratio (male-female) of the trapped adults with increase in periplanone-B used. An attempt has been made to explain the trapping of females and nymphs in addition to males by the chemicals used in our tests.     

Separation of ethyl acetate–isooctane mixture by heteroazeotropic batch distillation

This paper studies the separation of an ethyl acetate–isooctane mixture by heterogeneous azeotropic distillation in a batch rectifying column. An initial list of 60 candidates was studied but only methanol and acetonitrile were obtained as potential heterogeneous entrainers. These entrainers form a low boiling heterogeneous azeotrope with isooctane. Experimental verification of the miscibility gap with isooctane was performed at 25 °C for each entrainer giving a smaller region for methanol than for acetonitrile. Feasibility of the heterogeneous azeotropic batch distillation was carried out experimentally in a laboratory batch distillation column having 44 theoretical equilibrium stages and using a high reflux ratio. Several distillate fractions were taken as a function of the temperature at the top of the column. For both methanol and acetonitrile, the main fraction was defined by the condensed vapor providing a liquid–liquid split of the isooctane/entrainer heteroazeotrope into the decanter. Ethyl acetate impurity was detected in both decanted phases, but in much lower amount when using acetonitrile as entrainer. The process with acetonitrile also resulted in a shorter operating time and higher purity and recovery yield of isooctane as the main distillate product. Pure ethyl acetate remained into the boiler at the end of each process.     

Arrestment of male twospotted spider mite caused by female sex pheromone

A glass slide bioassay was used to evaluate male twospotted spider mite,Tetranychus urticae Koch, arrestment caused by quiescent deutonymph extract. Males that were guarding quiescent deutonymphs prior to being tested were arrested by a 3-mm-diameter circle of quiescent deutonymph extract; nonguarding males and adult females were not arrested. Extracts of allT. urticae instars tested caused male arrestment, but mean arrestment duration was longest with quiescent deutonymph extract. Arrestment by volatile perception of pheromone and upwind orientation to point sources of extract were not observed. The mono- and sesquiterpene alcohols previously identified as components of the pheromone did not arrest males. HPLC separation of extract resulted in four active fractions; a subtractive bioassay showed that three were essential to elicit maximum male response.     

Responses of gravid screwworm flies,Cochliomyia hominivorax,to whole wounds,wound fluid,and a standard blood attractant in olfactometer tests

Laboratory olfactometer bioassays were used to study attractiveness of whole animal wounds, wound fluid, and reconstituted dried blood to gravid screwworm flies,Cochliomyia hominivorax (Coquerel). Flies were attracted to odors from whole wounds that were infested with screwworm larvae but not to those from uninfested wounds that were 0–2 days old. A maximum of 59% of females were attracted to fluid from screwworminfested wounds, and the response changed little over fluid concentrations from 3.3 to 100%. However, blood tested over a similar concentration range yielded a significant linear relationship between log dose and response. Peak attraction was 82%. Attractancy of fluid collected from infested wounds declined when the fluid was stored at ? 20 °C for more than four weeks but attractancy of a stored blood sample remained unchanged for three months. The blood attractant(s) was also heat stable and is suitable for use as a reference standard in bioassays.     

Field Attraction of Hoplia communis to 2-Phenylethanol, A Major Volatile Component from Host Flowers, Rosa spp.

The attractiveness of volatile compounds from the floral scent of Rosa, one of the most preferred plants for adult Hoplia communis, was evaluated under field conditions. The beetles were attracted to most compounds tested, but 2-phenylethanol exhibited the highest capture rate. Catches increased with increasing emissions of between 9.1 and 287.2 mg/day. Catches in white traps were significantly larger (17.4-fold) than those in green traps when both were baited with anethole, an already known attractant; however, the trap color was not significant when a more attractive lure, 2-phenylethanol, was used. The use of a single funnel trap baited with 2 g of 2-phenylethanol at a heavily infested nursery exhibited promising results for mass trapping. Approximately 90,000 beetles of both sexes, which nearly corresponds to the estimated maximum population per 1000 m², were captured within six days.     

Chemical fractionation of shrimp extracts inducing bottom food search behavior in cod (Gadus morhua L.)

The bottom food search (BFS) feeding behavior in cod (Gadus morhua L.), has been used in a bioassay for chemical isolation of the feeding stimulant substances present in shrimp (Pandalus borealis). An aqueous methanol extract of ground shrimp was separated into acidic, neutral, and amphoteric/basic fractions by ion-exchange chromatography and into single components by preparative high-pressure liquid chromatography (HPLC). Of the isolated single components, the amino acid glycine was most potent, followed by alanine. Two unidentified substances were also highly potent. There was a synergistic effect between glycine, alanine, proline, and arginine. These four amino acids were more potent than the total amino acid pool found in the shrimp extract, indicating that there may be amino acids in this pool having an antagonistic effect.     

Attractancy toOryzaephilus surinamensis (L.) of volatile materials isolated from vacuum distillate of heat-treated carobs

Vacuum distillation of heat-treated carobs gave an aqueous, colorless, sweet-smelling distillate which was tested over a wide range of concentrations and found to be highly attractive to adultOryzaephilus surinamensis (L.). The materials responsible for the aroma were isolated from the distillate by saturating with sodium chloride and extracting into diethyl ether as separate acidic, neutral, and basic fractions. The extraction efficiency was checked by recombining portions of the three fractions and replacing the diethyl ether with water to give a reconstituted distillate; this was almost as attractive as the original distillate. Bioassay of aqueous solutions of the three separate fractions showed that the acidic was attractive, while the neutral and basic had little effect. The five major components of the acidic fraction were found to be acetic, isobutyric,n-butyric, 2-methylbutyric, and hexanoic (caproic) acids. Bioassay of these in aqueous solution, both separately and combined, showed that hexanoic acid was the most attractive and may be responsible for both the longer-lasting attractive effect of the carob distillate and for the effectiveness of carobs themselves used in bait bags to detect stored product insects.     

Identification of the Sex Pheromone of Holotrichia reynaudi

The male attractant pheromone of the scarab beetle Holotrichia reynaudi, an agricultural pest native to southern India, was extracted from abdominal glands of females with hexane and analyzed by gas chromatography–mass spectrometry. Field testing of the candidate chemicals, indole, phenol, and anisole, both alone and as binary mixtures, led us to conclude that anisole was the major component of the sex pheromone. Neither male nor female beetles were attracted to indole or phenol on their own. Similarly, when indole and anisole were combined, the attractiveness of the solution did not increase over that obtained with anisole alone. However, combination of phenol and anisole did alter the attractiveness of anisole, with fewer male beetles attracted to the binary mixture than to anisole on its own. The behavior of female beetles was not altered by any of the chemicals tested. Anisole is also the sex pheromone of H. consanguinea, making this the first known example of two melolonthine scarabs sharing the same pheromone.     

An h.p.l.e. and m.s. analysis of distillate fractions of neutral oil from hydrogenated Akabira coal to elucidate chemical structures

Akabira coal-derived neutral oil was separated into 25 narrow boiling range fractions covering 183–423 °C, and subsequently separated into compound class fractions : alkanes, monoaromatics, naphthalene-type diaromatics, fluorene-type diaromatics and tri- and/or tetraaromatics, by high performance liquid chromatography (h.p.l.c.). The compound type analyses of the distillate/h.p.l.c. fractions were performed using electron impact mass spectroscopy (e.i.m.s.) or field ionization mass spectroscopy (f.i.m.s.). Aromatic/hydroaromatic compound types and the alkyl side-chain carbon distribution of the distillate/h.p.l.c. fractions were clarified, based on the separation behaviour of h.p.l.c. and the type analyses according to Z value by m.s. By the distillation/h.p.l.c./m.s. method, coal-derived oil was characterized in terms of the distribution of the numbers of aromatic rings, naphthenic rings and carbons of alkyl groups attached to these rings. The variations in chemical structure in a compound class with distillation temperature are discussed in terms of these chemical structural factors.     

Chemoattraction ofBiomphalaria glabrata (Gastropoda: Planorbidae) to lipid standards and lipophilic factors in leaf lettuce and Tetramin

Chemoattraction of individualBiomphalaria glabrata snails for lipid standards and lipophilic fractions of leaf lettuce and Tetramin were studied in a Petri dish bioassay. Snails were more significantly attracted to a whole Tetramin lipophilic fraction than that of leaf lettuce. Thin-layer chromatography showed that major neutral lipid fractions in Tetramin were triacylglycerols, free fatty acids, and free sterols, and in leaf lettuce were free fatty acids and a mixed free sterol-chlorophyll fraction. Snails were significantly attracted to both the free fatty acid and free sterol fractions from Tetramin, but only to the free fatty acid fraction from leaf lettuce. Snails were significantly attracted to a mixed lipid standard containing equal amounts of phosphatidylcholine, cholesterol, oleic acid, triolein, and cholesteryl oleate. Of four individual neutral lipid standards tested, i.e., cholesterol, oleic acid, triolein, and cholesteryl oleate, snails were only attracted to cholesteryl oleate.     

焦化轻蜡油掺炼加氢柴油试验研究

通过实沸点蒸馏仪对加氢柴油进行精密分离,得到不同馏程温度段的窄馏分油,分析了不同窄馏分油的收率分布与烃类组成分布,分析结果表明：随着馏程温度升高,窄馏分油收率逐渐降低,加氢柴油中的链烷烃主要富集在馏程温度点高的窄馏分中,环烷烃与芳烃主要富集在馏程温度低的窄馏分中。焦化轻蜡油回炼加氢柴油窄馏分油后,加氢裂化产物65~175 ℃馏分收率增加,>175 ℃馏分收率均降低。由于窄馏分油中的烃类组成不同,所得加氢裂化产物性质有所差异。掺炼富含环烷烃与芳烃的窄馏分油所得65~175 ℃馏分芳潜值最高,掺炼链烷烃窄馏分油所得>175 ℃馏分的十六烷值指数最高。     

Attractants for synanthropic flies

Fermented molasses or sucrose solutions are known to attract several species of filth-breeding flies. To identify the volatile attractants produced in fermenting sucrose solutions with yeast, these solutions were fractionated, and the chemical constituents identified and bioassayed against filth-breeding flies includingFannia canicularis (L.),Muscina stabulans (Fallén), andMusca domestica (L.). Distillation of a fermented sucrose solution gave an active distillate and an inactive residue. Gas Chromatographic analysis of the distillate showed the presence of acetaldehyde, ethyl acetate, ethanol, 1-pro-panol, 2-methyl-l-propanol, and 3-methyl-l-butanol. Ethanol constituted by far the greatest proportion of compounds present in the distillate. An aqueous solution of ethanol exhibited the same level of attractancy as the distillate, the fermented sucrose solution, and a reconstituted distillate containing all compounds identified. Ethanol was thus identified as the sole attractant emanated from fermented carbohydrate solutions that elicited positive responses in pest flies, especially inF. canicularis.Diptera: Muscidae.     

Facile purification of tocopherols from soybean oil deodorizer distillate in high yield using lipase

Tocopherols have been purified from deodorizer distillate produced in the final deodorization step of vegetable oil refining by a process including molecular distillation. Deodorizer distillate contains mainly tocopherols, sterols, and free fatty acids (FFA); the presence of sterols hinders tocopherol purification in good yield. We found that Candida rugosa lipase recognized sterols as substrates but not tocopherols, and that esterification of sterols with FFA could be effected with negligible influence of water content. Enzymatic esterification of sterols with FFA was thus used as a step in tocopherol purification. High boiling point substances including steryl esters were removed from soybean oil deodorizer distillate by distillation, and the resulting distillate (soybean oil deodorizer distillate tocopherol concentrate; SODDTC) was used as a starting material for tocopherol purification. Several factors affecting esterification of sterols were investigated, and the reaction conditions were determined as follows: A mixture of SODDTC and water (4∶1, w/w) was stirred at 35°C for 24 h with 200 U of Candida lipase per 1 g of the reaction mixture. Under these conditions, approximately 80% of sterols was esterified, but tocopherols were not esterified. After the reaction, tocopherols and FFA were recovered as a distillate by molecular distillation of the oil layer. To enhance further removal of the remaining sterols, the lipase-catalyzed reaction was repeated on the distillate under the same reaction conditions. As a result, more than 95% of the sterols was esterified in total. The resulting reaction mixture was fractionated to four distillates and one residue. The main distillate fraction contained 65 wt% tocopherols with low contents of FFA and sterols. In addition, the residue fraction contained high-purity steryl esters. Because the process presented in this study includes only organic solvent-free enzymatic reaction and molecular distillation, it is feasible as a new industrial purification method of tocopherols. This work was presented at the Biocatalysis symposium in April 2000, held at the 91st Annual Meeting and Expo of the American Oil Chemists Society, San Diego, CA.     

Termination of aggregation by the European elm bark beetle,Scolytus multistriatus

The attractiveness of European elm bark beetle virgin females boring in elm logs declined within two days after the introduction of males. However, in the laboratory and in the field the number of beetles attracted to female-infested bolts was not depressed by the presence of separate logs infested with males or both sexes. It is concluded that the decline in attractiveness following cohabitation of the sexes results from termination of the production of attractant pheromone by mated females rather than the production of antiattractants by either sex.     

Attraction of adult sweet potato weevils,Cylas formicarius elegantulus (Summers), (Coleoptera: Curculionidae), to sweet potato leaf and root volatiles

A dual-choice olfactometer was developed to study the responses of sweet potato weevils,Cylas formicarius elegantulus (Summers), to volatiles from the sweet potato,Ipomoea batatas (L.) Lam. Both males and females were attracted by volatiles from sweet potato leaves and a methylene chloride leaf extract. Females, but not males, responded to volatiles from storage roots and a methylene chloride root extract. Leaves and storage roots from four sweet potato cultivars (Centennial, Jewel, Resisto, and Regal) were attractive to female weevils; however, the attractant response varied with cultivar. GC profiles from leaf and root extracts, and GC-MS analysis of leaf extract, for Jewel cultivar enabled the volatile peaks to be identified as sesquiterpenes.     

The Role of Recycle in Countercurrent Recycle Distillation Cascades. I. Constant Reflux,Ideal, and Squared-Off Cascades

Abstract

In most textbooks concerned with countercurrent multistage separations, minimum reflux ratio for continuous distillation is usually defined only in terms of a graphical construction on a McCabe—Thiele diagram: it is the recycle ratio (liquid flow rate) associated with the operating line that touches the equilibrium curve at the feed point. However, it is easily shown that minimum recycle ratio depends on local α and composition, as well as product compositions, and thus, it is a stage-composition phenomenon. As a result, for a specified separation, each ideal stage in a continuous distillation cascade has a specific minimum recycle ratio associated with it. For constant α, the minimum recycle ratio increases as the stage compositions depart more from product (distillate or bottoms) compositions. As a result, the textbooks only consider the maximum minimum recycle ratio. This paper presents the results of some theoretical calculations which illustrate how minimum recycle ratio varies with stage α, stage and product compositions, and presents an example of distillation cascade behavior when minimum recycle ratio is approached at a composition other than the feed point. An example is also presented which shows how the separation is effected when the reflux ratio is reduced below the design value in a distillation column containing a fixed number of ideal stages. A brief comparison is also made between constant reflux, ideal, and squared-off cascades in terms of number of stages, total interstage flow, and relative energy requirements for the different designs to illustrate and emphasize the consequences of the stagewise behavior of minimum recycle ratio.     

Separation of bio-oil by molecular distillation

In this study, KDL5 molecular distillation apparatus manufactured by the UIC Corporation was adopted to separate bio-oil, which came from a bench-scale fluidized-bed fast pyrolysis reactor at a feeding rate of 1 kg/h. A maximum distillate yield of 85% was obtained without obvious coking or polymerization during the molecular distillation process. The effect of distillation temperature on physical and chemical characterization of each bio-oil fraction was investigated. Statistical calculations showed that molecular distillation was successful in the separation of bio-oil. A separation factor was proposed to reflect the ability of isolating the chemicals contained in the bio-oil using molecular distillation.