Interference of beta-eudesmol in nestmate recognition in Atta sexdens rubropilosa (Hymenoptera: Formicidae).

Leaf-cutter ant species (Atta spp.) are key pests of cultivated crops in the Neotropics, and recent studies have demonstrated that workers of Atta spp., particularly of Atta sexdens rubropilosa, exhibit aggressive behavior among nestmates when in contact with the sesquiterpene beta-eudesmol, found in leaves of Eucalyptus maculata. However, the underlying mechanism sparking this behavior pattern has yet to be investigated. This work aimed to elucidate the mechanism by which this substance elicits aggression in workers of A. sexdens rubropilosa. The results, thus obtained, showed that beta-eudesmol is able to modify the chemical composition of the workers cuticle, impairing nestmate recognition, triggering alarm behavior and leading to nestmate aggression.

Responses of eucalypt species to aluminum: the possible involvement of low molecular weight organic acids in the Al tolerance mechanism.

Aluminum (Al) tolerance mechanisms in crop plants have been extensively researched, but our understanding of the physiological mechanisms underlying Al tolerance in trees is still limited. To investigate Al tolerance in eucalypts, seedlings of six species (Eucalyptus globulus Labill., Eucalyptus urophylla S.T. Blake, Eucalyptus dunnii Maiden, Eucalyptus saligna Sm., Eucalyptus cloeziana F. J. Muell. and Eucalyptus grandis w. Hill ex Maiden) and seedlings of six clones of Eucalyptus species were grown for 10 days in nutrient solutions containing Al concentrations varying from 0 to 2.5 microM (0 to 648 microM Al3+ activities). Root elongation of most species was inhibited only by high Al3+ activities. Low to intermediate Al3+ activities were beneficial to root elongation of all species and clones. Among the species tested, E. globulus and E. urophylla were more tolerant to Al toxicity, whereas E. grandis and E. cloeziana were more susceptible to Al-induced damage. Although E. globulus seedlings were tolerant to Al toxicity, they were highly sensitive to lanthanum (La), indicating that the tolerance mechanism is specific for Al. Fine roots accumulated more Al and their elongation was inhibited more than that of thick roots. In E. globulus, accumulation of Al in root tips increased linearly with increasing Al concentration in the nutrient solution. The majority of Al taken up was retained in the root system, and the small amounts of Al translocated to the shoot system were found mainly in older leaves. No more than 60% of the Al in the thick root tip was in an exchangeable form in the apoplast that could be removed by sequential citrate rinses. Gas chromatography/mass spectrometry and ion chromatography analyses indicated that root exposure to Al led to a greater than 200% increase in malic acid concentration in the root tips of all eucalypt species. The increase in malate concentration in response to Al treatment correlated with the degree of Al tolerance of the species. A small increase in citric acid concentration was also observed in all species, but there were no consistent changes in the concentrations of other organic acids in response to Al treatment. In all eucalypt species, Al treatment induced the secretion of citric and malic acid in root exudates, but no trend with respect to Al tolerance was observed. Thus, although malate and citrate exudation by roots may partially account for the overall high Al tolerance of these eucalypt species, it appears that tolerance is mainly derived from the internal detoxification of Al by complexation with malic acid.

Evaluation of the synthetic major component of the sex pheromone of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae).

In wind-tunnel bioassays, dispensers loaded with 1 microg of the synthetic major component (3E,8Z, 11Z)-3,8,11-tetradecatrienyl acetate (TDTA) of the sex pheromone emitted by Tuta absoluta (Meyrick) females were found to be highly attractive to conspecific males. Field experiments were conducted to evaluate the efficacy of five trap designs. The best trap, baited with 100 microg of the synthetic sex pheromone caught on average 1,200 males per trap per night, while those baited with virgin females caught only 201 males. The male response to this pheromone is restricted to the same early-morning time window during which females exhibit calling behavior. The high biological activity of the synthetic pheromone suggests that it could be useful for pest monitoring and in mating disruption.

Ergosterol accumulation and oil quality changes in stored soybean invaded by Aspergillus ruber (A. glaucus group).

Soybean seed samples inoculated with spores of Aspergillus ruber were stored for 20 to 140 days at 25 +/- 1 degrees C with moisture content varying from 11.3% to 17.7%. Seeds were colonised by the fungus within 20 days at all moisture levels. Ergosterol concentration in seeds increased with time of storage, being slow in samples with moisture content of 11.3% to 13.1% and more rapidly in those with higher moisture content. Free fatty acid (FFA) content also increased following the pattern of ergosterol. Equations were used to predict minimum safe storage period of the seeds at 25 degrees C. The rise in FFA is due to increase of A. ruber mass within the seed. Fungal growth did not affect fatty acids profiles or iodine index of the extracted oil. The results suggest revision of the present recommendations regarding seed moisture during storage. The FFA concentration of a seed lot can be used as a sensitive indicator of seed deterioration due to storage fungi.

Chromium contamination in sediment, vegetation and fish caused by tanneries in the state of Minas Gerais, Brazil.

In order to evaluate the chromium contamination from tannery discharges into rivers in the State of Minas Gerais, Brazil, samples of fluvial sediment, vegetation and fish were collected and submitted to chemical analysis. The chromium content in the samples was measured by atomic absorption spectrophotometry. Metal inputs were related to effluent discharges into the rivers. High concentrations of chromium were found in samples when compared with controls. Sediment investigations indicated strong enrichment and high geoaccumulation indices, while chromium concentrations in the analyzed vegetation were higher than those normally found in these materials. Chromium levels in fish exceeded 35 times the Brazilian recommendation value for human intake.

(3E,8Z,11Z)-3,8,11-tetradecatrienyl acetate, major sex pheromone component of the tomato pest Scrobipalpuloides absoluta (Lepidoptera: Gelechiidae).

The major sex attractant emitted by Scrobipalpuloides absoluta females is shown to be (3E,8Z,11Z)-3,8,11-tetradecatrien-1-yl acetate by a novel strategy involving the random reduction of double bonds, followed by methylthiolation of the reduced products. Each female sex gland contains ca. 1-5 ng of this pheromone. This triene ester, synthesized by a stereospecific procedure, shows spectral and gas chromatographic properties identical to those of the natural substance. In field tests and wind tunnel bioassays, the synthetic ester was found to be highly attractive to conspecific males. The male response to this pheromone, however, is restricted to the same early-morning time window during which females exhibit calling behavior.

Sex pheromone of tomato pestScrobipalpuloides absoluta (Lepidoptera: Gelechiidae).

The sex attractant ofScrobipalpuloides absoluta females is a 90:10 mixture of (3E,8Z,11Z)-3,8,11-tetradecatrien-1-yl acetate and (3E,8Z)-3,8-tetradecadien-1-yl acetate. Tetradecadienyl acetates bearing 8Z,11Z; 3E,8Z; and 3E,11Z double bonds were synthesized by stereospecific procedures; the mass spectral and gas chromatographic properties of the 3E,8Z isomer were found to be congruent with those of the tetradecadienyl acetate fromS. absoluta. In wind tunnel bioassays, a 10:1 mixture of synthetic (3E,8Z,11Z)-3,8,11-tetradecatrien-1-yl acetate and (3E,8Z)-3,8-tetradecadien-1-yl acetate was highly attractive toS. absoluta males. Interestingly, the presence of (8Z,11Z)-8,11-tetradecadien-1-yl acetate (10%) inhibited the response to (3E,8Z,11Z)-3,8,11-tetradecatrien-1-yl acetate completely.

Determination of double-bond position in some unsaturated terpenes and other branched compounds by alkylthiolation.

The electron-impact mass spectra of alpha, beta-bis(methylthio) derivatives of certain terpenes and other compounds with branched alkenyl groups contain diagnostic peaks that can be used for locating the position of the double bond in the parent compound. In contrast to the spectra of dimethyl disulfide (DMDS) derivatives obtained from compounds containing CH=CH type double bonds, which show two predominant fragment ions, most of the compounds examined in the current investigation showed only one predominant fragment ion, arising from that part of the molecule which possesses the more substituted carbon of the original double bond. For example, all the derivatives from compounds with an isopropylidene moiety showed a base peak at m/z89 which can be attributed to the formation of a [(CH3)2C=SCH3]+ fragment. The application of the DMDS procedure to naturally occurring terpenes is discussed.

Plasma amino acid and serum unesterified fatty acid deficits and the effect of nutritional support in chemotherapy treatment.

The deficits in plasma amino acids and serum unesterified fatty acids of cancer patients undergoing chemotherapy and/or radiation therapy were studied to delineate the special requirements of the patients and efficacy of our nutritional therapy. Seven general surgery patients and 13 patients treated by the Head-Neck Service had baseline levels measured as part of their nutritional evaluation prior to surgical treatment of their cancers. Fifteen chemotherapy outpatients maintained on their regular diets had fasting levels analyzed. Twenty-six patients who were admitted for their therapy had their intake of the regular hospital diet supplemented with a low-residue enteral diet formula (Vivonex High Nitrogen Diet); parenteral nutrition was used only if their oral intake was totally inadequate. Baseline and sequential measurements were made of plasma amino acid and serum unesterified fatty acid levels by gas liquid chromatographic techniques. Before operation the patients had normal levels of amino acids except for a significant deficiency of threonine and glycine observed in patients with head-neck tumors. Outpatients with and without hepatic metastases had significantly depressed levels of the essential amino acids valine, leucine, threonine, and methionine and the nonessential amino acids serine, glycine, and proline. The baseline levels of the patients admitted for treatment had similar deficiencies except for more evidence of lysine deficiency. Patients supported with total parenteral nutrition had rapid elevation of the amino acid levels. The patients whose intake was supplemented with the oral diets had improvement in their amino acid levels, but the deficiency in the leucine and threonine fractions persisted up to 4 weeks of therapy. Although the lysine levels were normal when first analyzed, significant differences developed in the patients without hepatic metastases after the start of chemotherapy with return to normal only after chemotherapy was discontinued. Fatty acid levels were not significantly different between the cancer groups except for preoperative elevated oleic acid levels noted in the general surgery tumor group; there were no deficiencies in the essential fatty acids. These studies indicate a need for enteral formulas with adequate branched-chain amino acids and enrichment with threonine and lysine for supplementing the nutrition of the cancer patient who is undergoing chemotherapy.

Gas chromatographic--mass spectrometric detection of circulating plasticizers in surgical patients.

Gas chromatographic and gas chromatographic--mass spectrometric analytical techniques were employed to quantitate and confirm levels of circulating organic plasticizers in critically ill surgical patients. Two plasticizers, dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP), have been identified. DEHP can be found in many plastic medical devices. The DEHP levels were significant soon after transfusion or in the presence of renal dysfunction. The source of DBP is not clear at present and requires further study. The prevention of this contamination and the toxicity of these plasticizers should be investigated to ensure the safe use of plastic medical devices.

The outcome of surgical treatment as related to the response of the serum albumin level to nutritional support.

Selected nutritional parameters were studied in critically ill surgical patients maintained by parenteral-enteral nutritional support to delineate the nutritional deficits and relate the course of these patients to the nutritional status. Twenty-one of 34 patients had albumin levels of less than 3.5 grams per cent upon admission, and the albumin levels decreased even further after admission. The patients with traumatic injuries had the greatest loss in body weight and urinary nitrogen excretion. Although such large numbers of these patients had depressed serum albumin levels, the survivors were able to increase the serum albumin level to 3.5 grams per cent with intense nutritional support, whereas those not surviving such support were not able to increase the serum albumin level. The response of the serum albumin level to nutritional support is a good indicator as to the same factors preventing survival and effective use of the nutritional elements.

Aporphines XXVI: GLC and mass spectrometric properties of trifluoracetyl derivatives of N-methyl-, N-propyl-, and noraporphines.

The O-trifluoroacetyl and N,O-trifluoroacetyl derivatives of a series of aporphine and noraporphine alkaloids were prepared, and their GLC and mass spectrometric characteristics were determined. The positional isomers apocodeine and isoapocodeine were resolved chromatographically as their trifluoroacetyl derivatives, and their mass spectra were distinctly different. Mass spectrometry fragmentation processes apparently unique to N-trifluoroacetyl derivatives of nonraporphines were observed. Plausible mechanisms for the formation of the major ions in the mass spectra of the various compounds are given.

Nutritional deficiencies and nutritional support therapy in geriatric cancer patients.

Nutritional deficits and their correction were studied in 45 cancer patients (age range, 60--86 years) who were undergoing various modalities of cancer therapy. Their nutritional status was maintained with a variety of commercially available special diets, and serum albumin concentrations were sequentially determined in order to gauge the efficacy of the nutritional support. Serum albumin levels were preserved when nutritional support was employed in surgical therapy. However, patients undergoing palliative chemotherapy or radiotherapy responded only to adequate levels of the standard hospital diet with or without supplements of special enteral diets. In the survivors, albumin levels were maintained; in the nonsurvivors, albumin levels decreased. This group of older patients tolerated nutritional support therapy, especially when it was carefully monitored. Satisfactory nutritional therapy can be achieved by use of appropriate enteral formulas. The method lends itself to adequate management in the outpatient or nursing-home situation during certain phases of cancer.

The absence of protein--sparing effects utilizing crystalline amino acids in stressed patients.

The protein-sparing effects of the peripheral infusion of crystalline amino acids (PAA) was studied metabolically in selected surgical patients subjected to various degrees of stress. Twenty-one patients (sixteen cancer patients receiving chemotherapy and/or radiotherapy, three with major abdominal traumatic injuries and four with paralytic ileus) were infused with 2 1/24 hours of a solution of 4.2% Travasol amino acids with only 5% glucose as a source of nonprotein calories. One-half of the cancer patients were also allowed ad libitum oral intake of a regular hospital diet or Vivonex-HN. The nutritional status was evaluated by measuring changes in body weight, serum albumin levels and nitrogen balance. Body weight decreased in only the trauma patients. When these solutions were the sole source of nutrients all patients were in negative nitrogen balance and had significant decreases in their serum albumin levels. Serum albumin levels were preserved only when extra sources of calories were provided. The infusion of the crystalline amino acids without adequate levels of nonprotein energy did not conserve protein in these stressed patients.