A mathematical comparison of classification structures: The case of the USDA Soil Taxonomy

Biologists have not paid much attention to the mathematical structures of biological classifications and their interpretations. A few have made such an analysis mainly using statistical distribution models. Comparisons with nonbiological classifications are needed to know if such structures are the result of biological evolution or of taxonomic practices, utilitarian bias, and/or subconscious cognitive rules. We compare the biological classification of a target group of soil borne plant parasitic nematodes (the Tylenchina suborder) with a non-biological one (the USDA 8th edition of the Keys to Soil Taxonomy). The authors made use of the same tools used in previous papers by biologists introducing other classifications. The results show that both taxonomies are information systems that try to optimize the information flow and fit well to the same distribution models. The analysis does not show any idiosyncrasies of biological classifications with respect to pedological ones, thus, supporting the idea that these products are the result of subconscious cognitive rules used by humankind to classify the world. Published in Russian in Pochvovedenie, 2006, No. 7, pp. 795–803. The text was submitted by the authors in English.     

Chemical composition and antifungal activity of essential oil of Chrysactinia mexicana gray

The chemical composition of the essential oil of Chysactinia mexicana was analyzed by gas chromatography-mass spectrometry. Seventeen compounds were characterized; eucalyptol (41.3%), piperitone (37.7%), and linalyl acetate (9.1%) were found as the major components. The essential oil of leaves and piperitone completely inhibited Aspergillus flavus growth at relatively low concentrations (1.25 and 0.6 mg/mL, respectively).     

In vivo bioinsecticidal activity toward Ceratitis capitata (fruit fly) and Callosobruchus maculatus (cowpea weevil) and in vitro bioinsecticidal activity toward different orders of insect pests of a trypsin inhibitor purified from tamarind tree (Tamarindus indica) seeds

A proteinaceous inhibitor with high activity against trypsin-like serine proteinases was purified from seeds of the tamarind tree (Tamarindus indica) by gel filtration on Shephacryl S-200 followed by a reverse-phase HPLC Vidac C18 TP. The inhibitor, called the tamarind trypsin inhibitor (TTI), showed a Mr of 21.42 kDa by mass spectrometry analysis. TTI was a noncompetitive inhibitor with a Ki value of 1.7 x 10(-9) M. In vitro bioinsecticidal activity against insect digestive enzymes from different orders showed that TTI had remarkable activity against enzymes from coleopteran, Anthonomus grandis (29.6%), Zabrotes subfasciatus (51.6%), Callosobruchus maculatus (86.7%), Rhyzopertha dominica(88.2%), and lepidopteron, Plodia interpuncptella (26.7%), Alabama argillacea (53.8%), and Spodoptera frugiperda (75.5%). Also, digestive enzymes from Diptera, Ceratitis capitata (fruit fly), were inhibited (52.9%). In vivo bioinsecticidal assays toward C. capitata and C. maculatus larvae were developed. The concentration of TTI (w/w) in the artificial seed necessary to cause 50% mortality (LD50) of larvae was 3.6%, and that to reduce mass larvae by 50.0% (ED50) was 3.2%. Furthermore, the mass C. capitata larvae were affected at 53.2% and produced approximately 34% mortality at a level of 4.0% (w/w) of TTI incorporated in artificial diets.     

Procyanidin fractions from pine (Pinus pinaster) bark: radical scavenging power in solution, antioxidant activity in emulsion, and antiproliferative effect in melanoma cells

Pine (Pinus pinaster) bark is a rich source of procyanidin oligomers. From a total polyphenolic extract, we have generated fractions of different procyanidin composition. The mixtures, devoid of gallate esters, were active as free radical scavengers against ABTS(*+), DPPH, and HNTTM. Pine bark fractions were tested for antioxidant activity in solution (hydrogen donation and electron transfer) and emulsion (inhibition of lipid peroxidation) and compared with their galloylated counterparts from grape origin. While galloylation clearly influenced the free radical scavenging efficiency in solution, it did not seem to play a determinant role in protection against lipid peroxidation in emulsion. The fractions were very mild inhibitors of cell proliferation. Because gallate esters appear to interfere with crucial cell functions, gallate free pine procyanidins may be the innocuous chemopreventative agents of choice for many applications in food and skin protection.     

Evaluation of the antioxidant capacity of individual phenolic compounds in virgin olive oil

Virgin olive oil has a high resistance to oxidative deterioration due to its tryacylglycerol composition low in polyunsaturated fatty acids and due to the presence of a group of phenolic antioxidants composed mainly of polyphenols and tocopherols. We isolated several phenolic compounds of extra virgin olive oil (phenyl-ethyl alcohols, lignans, and secoiridoids) by semipreparative high-performance liquid chromatography (HPLC) and identified them using ultraviolet, atmospheric pressure chemical ionization, and electrospray ionization MS detection. The purity of these extracts was confirmed by analytical HPLC using two different gradients. Finally, the antioxidant capacity of the isolated compounds was evaluated by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radical, by accelerated oxidation in a lipid model system (OSI, oxidative stability instrument), and by an electrochemical method.     

Isoflavonoids isolated from Cuban propolis

Chemical investigation of a red-type Cuban propolis sample has led to the isolation of 11 isoflavonoids (2 isoflavones, 3 isoflavans, and 6 pterocarpans), together with gallic acid, isoliquiritigenin, and (-)-liquiritigenin. Structural determination, including the absolute stereochemistry, was accomplished by spectroscopic analysis, particularly CD and 2D NMR techniques. The fragmentation behavior of pterocarpans was studied by electrospray ionization (ESI) tandem mass spectrometry (MS/MS) using an ion-trap analyzer, and a generalized fragmentation pathway, useful in the identification and structural characterization of pterocarpans, is proposed. Isoflavonoids are reported for the first time from propolis samples.     

Effect of processing and storage on the antioxidant ellagic acid derivatives and flavonoids of red raspberry (Rubus idaeus) jams

From red raspberries, ellagic acid, its 4-arabinoside, its 4' (4' '-acetyl) arabinoside, and its 4' (4' '-acetyl)xyloside, as well as quercetin and kaempferol 3-glucosides, were identified. In addition, two unidentified ellagic acid derivatives were detected. The free radical scavenging activity of the ellagic acid derivatives was evaluated by using the DPPH method and compared to that of Trolox. All of the isolated compounds showed antioxidant activity. The effect of processing to obtain jams on raspberry phenolics was evaluated. The flavonol content decreased slightly with processing and more markedly during storage of the jams. The ellagic acid derivatives, with the exception of ellagic acid itself, remained quite stable with processing and during 6 months of jam storage. The content of free ellagic acid increased 3-fold during the storage period. The initial content (10 mg/kg of fresh weight of raspberries) increased 2-fold with processing, and it continued increasing up to 35 mg/kg after 1 month of storage of the jam. Then a slight decrease was observed until 6 months of storage had elapsed. The increase observed in ellagic acid could be explained by a release of ellagic acid from ellagitannins with the thermal treatment.     

Postharvest induction modeling method using UV irradiation pulses for obtaining resveratrol-enriched table grapes: a new "functional" fruit?

A modeling method for the induction of resveratrol synthesis by UV irradiation pulses in Napoleon table grapes is proposed. The method is based on the combination of four main parameters: irradiation power (IW), irradiation time (IT), irradiation distance (ID), and number of elapsed days to achieve the highest resveratrol accumulation (D(m)). Maximum resveratrol content (11-fold higher than untreated grapes) was achieved using the combination: IW = 510 W, IT = 30 s, ID = 40 cm, and D(m) = 3 days. Sensory characteristics and main features of irradiated grapes (color, weight, firmness, flavor, size, ripening index and vitamin C content) remained unaltered after 1 week of storage. UV induction signal migrated to the hidden side of the grape skin with a delay of 3 days as compared to the directly irradiated side. Phenolic compounds were not detected in Napoleon grape flesh. Resveratrol content per standard serving (200 g) of irradiated grape was about 3 mg, an amount more than 10-fold higher than that of untreated Napoleon grapes. This means that a serving of irradiated grape (unpeeled) could supply the resveratrol content equivalent to 3 glasses of a red wine with high resveratrol content ( approximately 1 mg/glass). Therefore, controlled UV irradiation pulses are useful as a simple postharvest treatment (and alternative to genetic engineering) to obtain possible "functional" grapes (with enhanced health-promoting properties) as a dietary source of high resveratrol content.     

Phytoextraction of Cd and Pb and physiological effects in potato plants (Solanum tuberosum var. Spunta): importance of root temperature.

Three consecutive years of field experiments were carried out to investigate the effect of different root-zone temperatures, induced by the application of mulches, on the concentration and accumulation of Cd and Pb and on bioindicators (chlorophylls, catalase, peroxidase and cell wall fractions) in different organs of potato plants (roots, tubers, stems, and leaflets). Four different plastic covers were employed (T1, transparent polyethylene; T2, white polyethylene; T3, white and black coextruded polyethylene, and T4, black polyethylene), using uncovered plants as the control (T0). The different treatments had a significant effect on the mean root-zone temperatures (T0 = 16 degrees C, T1 = 20 degrees C, T2 = 23 degrees C, T3 = 27 degrees C, and T4 = 30 degrees C) and induced significantly different responses in the Cd and Pb concentrations and phytoaccumulation, with T2 (23 degrees C) and T3 (27 degrees C) giving high concentrations of Cd in the roots and low concentrations in other organs. In relation to Pb, T2 and T3 reached higher levels in the tubers and lower levels in the roots, stems, and leaves. In terms of phytoaccumulation, the roots and tubers were the most effective organs for Cd and Pb. On the other hand, the highest values of peroxidase and catalase activities were obtained for T3. In addition, most of the carbohydrate fractions in both the roots and the tubers were highest for T3. Meanwhile, the lowest pigment values were registered for T1 (20 degrees C). For phytoremediation, it is necessary to ascertain the relevance and control of the thermal regime of the soil to optimize the phytoextraction of pollutant elements (Cd and Pb).     

Oxidation of salsolinol by banana pulp polyphenol oxidase and its kinetic synergism with dopamine

Salsolinol, a tethrahydroisoquinoline present in banana and biosynthesized from dopamine, was oxidized by banana pulp polyphenol oxidase to its corresponding salsolinol-o-quinone. This oxidation was pH-dependent and showed a maximum at acidic pH values. At physiological pH of 5.0, the values obtained for the kinetic parameter (V(m) and K(m)) were 62.5 microM/min and 1.7 mM, respectively. When dopamine was added to the reaction medium to imitate physiological conditions, salsolinol was co-oxidized by dopamine-quinone. When this phenomenon was studied oxygraphically, an unexpected activation of dopamine oxidation was found in the presence of salsolinol. This activation was related with the enzyme's kinetic mechanism and was named "kinetic synergism", because a bad substrate activated a good one. A possible physiological role is discussed.