Biology of the immature stages of Strymon crambusa (Lycaenidae, Theclinae) on Oxalidaceae

ABSTRACT We document the biology and morphology of the egg, caterpillar, and pupa of Strymon crambusa (Hewitson, 1874), a Neotropical Eumaeini. In the Cerrado, the caterpillar feeds on the inflorescences and leaves of Oxalis L. S. crambusa has four larval instars, all of which are illustrated. The density of caterpillars on plants is higher than that recorded for leaf-feeding caterpillars and other flower-feeding Eumaeini, which suggests that the species is a specialist on Oxalidaceae in the Cerrado.

The global distribution of diet breadth in insect herbivores.

Understanding variation in resource specialization is important for progress on issues that include coevolution, community assembly, ecosystem processes, and the latitudinal gradient of species richness. Herbivorous insects are useful models for studying resource specialization, and the interaction between plants and herbivorous insects is one of the most common and consequential ecological associations on the planet. However, uncertainty persists regarding fundamental features of herbivore diet breadth, including its relationship to latitude and plant species richness. Here, we use a global dataset to investigate host range for over 7,500 insect herbivore species covering a wide taxonomic breadth and interacting with more than 2,000 species of plants in 165 families. We ask whether relatively specialized and generalized herbivores represent a dichotomy rather than a continuum from few to many host families and species attacked and whether diet breadth changes with increasing plant species richness toward the tropics. Across geographic regions and taxonomic subsets of the data, we find that the distribution of diet breadth is fit well by a discrete, truncated Pareto power law characterized by the predominance of specialized herbivores and a long, thin tail of more generalized species. Both the taxonomic and phylogenetic distributions of diet breadth shift globally with latitude, consistent with a higher frequency of specialized insects in tropical regions. We also find that more diverse lineages of plants support assemblages of relatively more specialized herbivores and that the global distribution of plant diversity contributes to but does not fully explain the latitudinal gradient in insect herbivore specialization.

Larval biology of anthophagous Eumaeini (Lepidoptera: Lycaenidae, Theclinae) in the cerrado of central Brazil.

The biology and morphology of the early stages of 22 species of Eumaeini (Lepidoptera: Lycaenidae, Theclinae) are presented. Observations were collected through the inspection of inflorescences in the field and the rearing of 214 larvae in laboratory. Allosmaitia strophius (Godart) associated with Malpighiaceae species and the polyphagous Strymon mulucha (Hewitson) were the most frequently collected species. Detritivory was observed in two species, Electrostrymon endymion (F.) and Kisutam syllis (Godman & Salvin), and myrmecophily in four other species, A. strophius, Ministrymon azia (Hewitson), Parrhasius polibetes (Stoll), and S. mulucha. Cannibalism was observed in A. strophius; in addition, the pupa of this and of three other species produced audible sounds. Paiwarria aphaca (Hewitson) was highlighted because of the great difference observed between its first and last instars, as well as the marked difference between that species and the larvae of Paiwarria umbratus (Geyer) documented in Costa Rica. Larvae of Calycopis mimas (Godman & Salvin) displayed "bungee jumping" behavior when stimulated. Parasitoids (Diptera, Hymenoptera) attacked 21 larvae of eight species, A. strophius, K. syllis, M. azia, Pai. aphaca, P. polibetes, Rekoa marius (Lucas), S. mulucha, and Tmolus venustus (H.H. Druce). Illustrations of immatures and parasitoids are provided.

Aspectos biológicos de Heliopetes arsalte (Linnaeus, 1758) (Hesperiidae, Pyrginae) em cerrado do Distrito Federal / Biological aspects of Heliopetes arsalte (Linnaeus, 1758) (Hesperiidae, Pyrginae) in cerrado of Federal District

Heliopetes arsalte (Linnaeus, 1758) (Hesperiidae, Pyrginae) é uma espécie com ampla distribuição, especialmente em vegetação aberta, e suas larvas utilizam diversas espécies de Malvaceae como plantas hospedeiras. Larvas de H. arsalte foram encontradas em inflorescências de Pavonia rosa-campestris St. Hil. (Malvaceae), sendo este um novo registro de planta hospedeira desta espécie de borboleta no cerrado do Brasil central. Ilustrações de ovo, da larva e da pupa, e a ocorrência de parasitismo da larva por Braconidae (Hymenoptera) são apresentadas.

Heliopetes arsalte (Linnaeus, 1758) (Hesperiidae, Pyrginae) is a widespread skipper butterfly, commonly found in open sites. The larvae may utilize several species of Malvaceae as host plants. In this study, larvae of H. arsalte were observed on inflorescences of Pavonia rosa-campestris St. Hil. (Malvaceae), which represents a new record of host plants for this butterfly in cerrado of central Brazil. Illustrations of the immature and adult stages, as well as the occurrence of parasitism by Braconidae (Hymenoptera) are presented.

Padrão de oviposição e tabela de vida da traça-do-tomateiro Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae) / Oviposition pattern and life table of South American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae)

A traça-do-tomateiro apresentou maior oviposição ao colonizar tomateiros cultivados em sistema convencional em relação ao orgânico em estudos prévios realizados no campo. Visando confirmar e entender o padrão observado no campo, aspectos bioecológicos como oviposição e mortalidade de imaturos foram comparados em condições semi-controladas de casa de vegetação com plantas cultivadas em vasos com solo proveniente do sistema orgânico e convencional. Adultos da traça-do-tomateiro foram liberados na casa de vegetação e após 24h, as plantas infestadas foram transferidas para outra casa de vegetação, para acompanhamento de coortes horizontais. Os ovos naturalmente depositados pela traça-do-tomateiro foram localizados na planta e demarcados. Em seguida, a folha foi ensacada. Diariamente as plantas foram observadas, registrando a fase de desenvolvimento do inseto e a ocorrência de morte, até que todos os insetos completassem seu ciclo de vida. A oviposição pela traça-do-tomateiro em plantas com solos oriundos do sistema convencional foi duas vezes maior do que em plantas com solos do sistema orgânico. A curva de sobrevivência da fase imatura e a tabela de vida da traça-do-tomateiro em casa de vegetação mostraram que a sobrevivência em plantas com solo orgânico e convencional não apresentaram diferenças. Assim as diferenças no comportamento de padrão de oviposição observadas a campo provavelmente não estão relacionadas com o desempenho da progênie e podem ser influenciado pelo ambiente proporcionado pelo sistema orgânico de produção.

The tomato pinworm presented higher oviposition when colonizing tomato plants cropped in conventional system than in organic system, in previous field studies. Aiming to confirm and to understand the observed pattern in the field, bioecological processes, such as oviposition and mortality of immatures, were compared on ploted plants in soil from organic and conventional systems in semi-controlled conditions of greenhouse. Tomato pinworm adults were released in the greenhouse, the infested plants were transfered to another greenhouse after 24h, to track horizontal cohort. Naturally deposited eggs were located, marked and the leaf was caged. Each plant was observed daily and development stage or death was registered until all individuals completed the life cycle or died. Oviposition by tomato pinworm was 2-fold higher in plants growing in soil from conventional system than from organic system. The survivorship curve of immatures and life table in the greenhouse showed that there was no difference in organic and conventional plants. Thus, the difference in the oviposition pattern observed in the field is not related to the progeny performance and can be influenced by the environment of organic tomato crop system.

Abundance and temporal distribution of Gonioterma exquisita Duckworth (Lepidoptera, Elachistidae, Stenomatinae) on Byrsonima pachyphylla Griseb. (Malpighiaceae) in the Brazilian Cerrado

The seasonal characteristics of the Cerrado region strongly influence food resource predictability and vegetal tissue nutritional content. The aims of this work were to record the abundance and temporal distribution of Gonioterma exquisita Duckworth, 1964 (Lepidoptera, Elachistidae) and its relation with phenological, physical, and chemical traits of the host plant Byrsonima pachyphylla Griseb. (Malpighiaceae). Four nutritional quality parameters were determined for new and mature leaves: gross protein and nitrogen content, dry matter, and in vitro digestibility. We inspected 200 plants per month, searching for G. exquisita caterpillars. About 35.8 percent of the 2,400 plants inspected presented caterpillars, with an abundance peak in the wet season. Caterpillar abundance was positively correlated with mature leaf availability, their food resource. Although mature leaves presented lower gross protein and nitrogen contents than new leaves, this difference was small during the abundance peak of G. exquisita.

As características sazonais da região do Cerrado influenciam fortemente a previsibilidade dos recursos alimentares no tempo e no espaço como também a qualidade nutricional dos tecidos vegetais. Os objetivos deste trabalho foram registrar a abundância e a distribuição temporal de Gonioterma exquisita Duckworth, 1964 (Lepidoptera, Elachistidae) e sua relação com aspectos fenológicos, físicos e químicos de sua planta hospedeira, Byrsonima pachyphylla Griseb. (Malpighiaceae). Quatro parâmetros nutricionais foram determinados para folhas novas e maduras: proteína bruta, conteúdo de Nitrogênio, matéria seca e digestibilidade in vitro. Inspecionamos, mensalmente, 200 plantas a procura de lagartas de G. exquisita. Das 2.400 plantas inspecionadas, 35.8 por cento apresentaram lagartas e seu pico de abundância ocorreu na estação chuvosa. A abundância de lagartas mostrou correlação positiva com a disponibilidade de folhas maduras, seu recurso alimentar. Embora as folhas maduras tenham apresentado taxas menores de proteína bruta e de Nitrogênio que as folhas novas, esta diferença foi muito pequena durante o pico de abundancia de G. exquisita.

Temporal and spatial variation of Stenoma cathosiota Meyrick (Lepidoptera: Elachistidae) caterpillar abundance in the cerrado of Brasilia, Brazil

The caterpillars of Stenoma cathosiota Meyrick feed on Roupala montana Aubl. (Proteaceae) in the cerrado of the Distrito Federal, Brazil. They construct shelters by joining leaves of the plant where they feed and pupate. The caterpillars are parasitized by a wasp (Hymenoptera: Brachonidae), which emerges from the pupae. Caterpillar abundance and parasitism frequency were associated in an area of frequently burned cerrado (biennial fire) and in another area that burns sporadically (1987 and 1994). For S. cathosiota, the variation among years in a single area, with sporadic fires, was greater than the variation among areas with different fire regimes. Caterpillar abundance among years was significantly different in the area that burns sporadically (chi² = 24.06; df. = 1; P = 0.000). However, there were no significant differences on caterpillar abundance between areas for the same period (chi² = 3.45; df. = 1; P = 0.063). Parasitism frequency was high, reaching 29 percent of the collected caterpillars, and did not differ among areas. The great temporal variation in abundance of lepidopteran caterpillars in the cerrado makes it difficult to determine the effects that fire exerts over this fauna.

As lagartas da mariposa Stenoma cathosiota Meyrick alimentam-se de folhas de Roupala montana Aubl. (Proteaceae) em áreas de cerrado do Distrito Federal. Elas constroem abrigos juntando folhas da planta onde se alimentam e empupam. São parasitadas por uma vespa (Hymenoptera: Braconidae) que emerge da pupa. A abundância de lagartas de S. cathosiota e a freqüência do parasitismo foram comparadas em duas áreas de estudo: uma com queimadas freqüentes (bienal) e a outra com queimadas esporádicas (1987 e 1994). Na área com baixa freqüência de queimada, a variação na abundância das lagartas entre anos foi significativamente diferente (chi² = 24,06; gl. = 1; P = 0,000). No entanto, a variação na abundância de lagartas entre áreas, para o mesmo período de tempo, não diferiu estatisticamente (chi² = 3,45; gl. = 1; P = 0,063). A freqüência do parasitismo foi alta, ocorrendo em 29 por cento das lagartas coletadas e não diferiu entre as áreas. A grande variação temporal na abundância de lagartas no cerrado dificulta a determinação dos efeitos do fogo sobre essa fauna.

Biology and occurrence of Inga Busk species (Lepidoptera: Oecophoridae) on Cerrado host plants.

We sampled Inga Busk species caterpillars weekly in the cerrado on 15 plants of Diospyros burchellii Hern. (Ebenaceae) from January 2002 to December 2003, on 30 plants of Caryocar brasiliense (Caryocaraceae) from July 2003 to June 2004, and since 1991 on several other plant species. In total we found 15 species of Inga on cerrado host plants. Nine species were very rare, with only one to five adults reared. The other six species occurred throughout the year, with higher abundance during the dry season, from May to July, coinciding with overall peaks of caterpillar abundance in the cerrado. Caterpillars of the genus Inga build shelters by tying and lining two mature or old leaves with silk and frass, where they rest and develop (a common habit found in Oecophorinae). The final instar builds a special envelope inside the leaf shelter, where it will complete the larval stage and pupate. The species are very difficult to distinguish in the immature stages. External features were useful in identifying only four species: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). These four species are polyphagous and have wide geographical distributions. In this paper we provide information on the natural history and host plants of six Inga species common on cerrado host plants, for which there are no reports in the literature.

Biology and occurrence of Inga Busk species (Lepidoptera: Oecophoridae) on Cerrado host plants

We sampled Inga Busk species caterpillars weekly in the cerrado on 15 plants of Diospyros burchellii Hern. (Ebenaceae) from January 2002 to December 2003, on 30 plants of Caryocar brasiliense (Caryocaraceae) from July 2003 to June 2004, and since 1991 on several other plant species. In total we found 15 species of Inga on cerrado host plants. Nine species were very rare, with only one to five adults reared. The other six species occurred throughout the year, with higher abundance during the dry season, from May to July, coinciding with overall peaks of caterpillar abundance in the cerrado. Caterpillars of the genus Inga build shelters by tying and lining two mature or old leaves with silk and frass, where they rest and develop (a common habit found in Oecophorinae). The final instar builds a special envelope inside the leaf shelter, where it will complete the larval stage and pupate. The species are very difficult to distinguish in the immature stages. External features were useful in identifying only four species: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). These four species are polyphagous and have wide geographical distributions. In this paper we provide information on the natural history and host plants of six Inga species common on cerrado host plants, for which there are no reports in the literature.

Dada a ausência de informações sobre a biologia de lagartas que ocorrem em plantas de cerrado, apresentamos aqui algumas informações sobre larvas do gênero Inga Busk. Lagartas foram coletadas, semanalmente, em 15 indivíduos de Diospyros burchelli Hern. (Ebenaceae), de janeiro de 2002 a dezembro de 2003, em 30 indivíduos de Caryocar brasiliense Camb. (Caryocaraceae), de julho de 2003 a junho de 2004 e, em várias outras espécies de plantas desde 1991. No total foram encontradas 15 espécies de Inga em plantas de cerrado, no DF. Nove espécies foram raras com até cinco adultos obtidos em criação no laboratório. As outras seis espécies ocorreram durante o ano sendo mais abundantes entre maio e julho (estação seca), o que coincide com a época de maior abundância de lagartas no cerrado. As lagartas do gênero Inga constroem abrigos, juntando duas folhas maduras ou velhas com fios de seda, onde se alimentam e desenvolvem (um hábito comum entre os Oecophorinae). Larvas de último instar constroem, dentro do abrigo, um tipo de envelope onde completam seu desenvolvimento e empupam. A separação das espécies das lagartas é muito difícil. Características externas permitem o reconhecimento de apenas quatro espécies de Inga: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). Essas quatro espécies têm ampla distribuição geográfica e são polífagas. Neste artigo, apresentamos informações não encontradas na literatura sobre a história natural de seis espécies de Inga comuns em plantas hospedeiras de cerrado.

Temporal and spatial variation of Stenoma cathosiota Meyrick (Lepidoptera: Elachistidae) caterpillar abundance in the cerrado of Brasilia, Brazil.

The caterpillars of Stenoma cathosiota Meyrick feed on Roupala montana Aubl. (Proteaceae) in the cerrado of the Distrito Federal, Brazil. They construct shelters by joining leaves of the plant where they feed and pupate. The caterpillars are parasitized by a wasp (Hymenoptera: Brachonidae), which emerges from the pupae. Caterpillar abundance and parasitism frequency were associated in an area of frequently burned cerrado (biennial fire) and in another area that burns sporadically (1987 and 1994). For S. cathosiota, the variation among years in a single area, with sporadic fires, was greater than the variation among areas with different fire regimes. Caterpillar abundance among years was significantly different in the area that burns sporadically (chi2 = 24.06; df. = 1; P = 0.000). However, there were no significant differences on caterpillar abundance between areas for the same period (chi2 = 3.45; df. = 1; P = 0.063). Parasitism frequency was high, reaching 29% of the collected caterpillars, and did not differ among areas. The great temporal variation in abundance of lepidopteran caterpillars in the cerrado makes it difficult to determine the effects that fire exerts over this fauna.

Lepidópteros folívoros em Roupala montana Aubl. (Proteaceae) no Cerrado Sensu Stricto / Folivore caterpillars on Roupala montana Aubl. (Proteaceae) in Cerrado Sensu Stricto

No cerrado a riqueza de espécies de lepidópteros é alta e confirmada por registros de adultos, mas o conhecimento sobre as interações das lagartas com suas plantas hospedeiras ainda é incipiente. Os objetivos deste trabalho foram conhecer a riqueza de espécies de lepidópteros folívoros em Roupala montana Abl., a idade relativa das folhas consumidas pelas espécies e suas amplitudes de dietas. Os dados foram coletados em áreas de cerrado sensu stricto de Brasília de 1991 a 2004. As lagartas encontradas foram coletadas e criadas no laboratório. Foram registradas 62 espécies de lepidópteros de 22 famílias, consumindo folhas jovens (8 por cento) e maduras (92 por cento) de R. montana. Cerconota sciaphilina (Zeller) (Elachistidae), duas espécies de Gracillariidae e uma de Gelechiidae consumiram somente folhas jovens e, apresentaram ciclo de vida curto e sincronizado com a fenologia foliar da planta hospedeira. Das espécies que consomem folhas maduras, 36 foram consideradas polífagas e mostraram variação muito grande na utilização do recurso. Vinte e seis espécies foram encontradas somente em R. montana, sendo que 58 por cento delas são bastante raras, o que dificulta análise de amplitude de dieta. As espécies monófagas em R. montana foram Chlamydastis platyspora (Meyrick) (Elachistidae), Stenoma cathosiota Meyrick (Elachistidae), Idalus prop. sublineata (Rothschild) (Arctiidae) e Eomichla sp. (Oecophoridae).

[Folivore caterpillars on Roupala montana Aubl. (Proteaceae) in cerrado sensu stricto]. / Lepidópteros folívoros em Roupala montana Aubl. (Proteaceae) no cerrado sensu stricto.

Richness of lepidopteran species in the cerrado is high. The confirmation of this richness is based on adult records but knowledge of larvae-host plants interactions is still incipient. The main purpose of this work was to identify folivorous caterpillar species on Roupala montana Aubl. in areas of a Brazilian cerrado sensu stricto, their dietary range, and the relative age of the consumed leaves richness. Three data sets, collected from 1991 to 2004 were used in this study. All caterpillars found on the host plants in the field were collected and reared in the laboratory. Sixty-two lepidopteran species from 22 families were recorded; they were found feeding on new (8%) and mature (92%) leaves of R. montana. Cerconota sciaphilina (Zeller) (Elachistidae), two unidentified Gracillariidae species and, one species of Gelechiidae fed only on new leaves. These species showed a short life cycle, which was very syncronized with the host plant foliar phenology. Among the species feeding on mature leaves, 36 were considered polyphagous and, these showed a large variation in the use of the food resource. Twenty-six species were found only on R. montana, 58% were very rare, a character that difficults the analysis of their dietary range. The monophagous species on R. montana were: Chlamydastisplatyspora (Meyrick) (Elachistidae), Stenoma cathosiota Meyrick (Elachistidae), Idalus prop. sublineata (Rothschild) (Arctiidae), and Eomichla sp. (Oecophoridae).

Aprendizagem e eficiência da predação: uma abordagem didática / Learning and efficiency of predation: a teaching approach

O efeito da experiência do predador na eficiência de predação foi examinado utilizando estudantes e docentes do curso de Ciências Biológicas da Universidade de Brasília. As presas foram larvas de Lepidoptera, folívoras externas, expostas ou em abrigos nas plantas do cerrado de Brasília. Foram usados três conjuntos de predadores: 1. Inexperientes – calouros; 2. Experiência variada – estudantes do 3º ao último semestre do curso; 3. Experientes – docentes e estudantes com experiência nos projetos com lagartas no campo. A primeira vistoria das plantas marcadas foi feita pelos predadores 1 ou 2 que coletaram todas as larvas encontradas. Logo em seguida as mesmas plantas foram examinadas pelos predadores experientes (grupo 3). Os testes foram feitos em 1998, 2000 e 2003 e, em todos eles, os predadores experientes foram mais eficientes na detecção de presas, encontrando sempre um número maior de larvas (27 a 85 por cento) e de plantas com larvas (18 a 76 por cento)

Aprendizagem e eficiência da predação: uma abordagem didática / Learning and efficiency of predation: a teaching approach

O efeito da experiência do predador na eficiência de predação foi examinado utilizando estudantes e docentes do curso de Ciências Biológicas da Universidade de Brasília. As presas foram larvas de Lepidoptera, folívoras externas, expostas ou em abrigos nas plantas do cerrado de Brasília. Foram usados três conjuntos de predadores: 1. Inexperientes – calouros; 2. Experiência variada – estudantes do 3º ao último semestre do curso; 3. Experientes – docentes e estudantes com experiência nos projetos com lagartas no campo. A primeira vistoria das plantas marcadas foi feita pelos predadores 1 ou 2 que coletaram todas as larvas encontradas. Logo em seguida as mesmas plantas foram examinadas pelos predadores experientes (grupo 3). Os testes foram feitos em 1998, 2000 e 2003 e, em todos eles, os predadores experientes foram mais eficientes na detecção de presas, encontrando sempre um número maior de larvas (27 a 85 por cento) e de plantas com larvas (18 a 76 por cento) (AU)

Effect of tributylphenyltetraethoxylate on enzyme production of Pleurotus ostreatus.

The effect of the addition of the nonionic surfactant tributylphenyltetraethoxylate to culture media on pH and extracellular protein content, and on production of beta-glucosidase, xylanase, laccase, and manganese-dependent and -independent peroxidases by the edible fungus Pleurotus ostreatus was determined. The relationship between fermentation parameters and concentration of surfactant was assessed by multiple linear regression analysis, and the similarities and differences among the fermentation parameters were elucidated by principal component analysis. Calculations proved that except for xylanase all other cultivation parameters were significantly influenced by the surfactant, with the effect higher at higher surfactant concentrations. Surfactant increased the production of beta-glucosidase and inhibited laccase and manganese-dependent and -independent peroxidase activities.

Effect of reduced glutathione on the stability of pigments in paprika powders studied by multiwavelength spectrometry and high-performance liquid chromatography.

Multiwavelength spectrometry and reversed-phase high-performance liquid chromatography have been employed for the study of the effect of reduced glutathione and storage time on the pigments of paprika powders. The evaluation of the data by principal component analysis and cluster analysis proved that the storage time exerts the highest effect of the decomposition rate of pigments. The stability of some pigment fractions was modified in the presence of reduced glutathione. However, the effect was of secondary importance. Multiwavelength spectrometry combined with HPLC can be successfully used for the study of the stability of pigments of paprika powder.

Liquid chromatographic and electrophoretic characterisation of extracellular beta-glucosidase of Pleurotus ostreatus grown in organic waste.

The production of beta-glucosidase by the ligninolytic fungus Pleurotus ostreatus has been studied in different culture media containing agro-industrial wastes. The enzyme is purified by anion-exchange chromatography, the molecular mass and isoelectric point of purified beta-glucosidase are measured by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing and the stability and kinetic parameters of the enzyme assessed by spectrophotometry. It has been established that the retention time, molecular mass and isoelectric point of the enzyme depend on the composition of the culture media while the activity and stability of beta-glucosidases of different origin were very similar. The combined chromatographic and electrophoretic methods have proved to be suitable techniques for the purification and characterisation of the beta-glucosidases produced by the ligninolytic fungus Pleurotus ostreatus in different culture media.

Influence of storage conditions on the stability of monomeric anthocyanins studied by reversed-phase high-performance liquid chromatography.

The effect of light, storage time and temperature on the decomposition rate of monomeric anthocyanin pigments extracted from skins of grape (Vitis vinifera var. Red globe) was determined by reversed-phase high-performance liquid chromatography (RP-HPLC). The impact of various storage conditions on the pigment stability was assessed by stepwise regression analysis. RP-HPLC separated well the five anthocyanins identified and proved the presence of other unidentified pigments at lower concentrations. Stepwise regression analysis confirmed that the overall decomposition rate of monomeric anthocyanins, peonidin-3-glucoside and malvidin-3-glucoside significantly depended on the time and temperature of storage, the effect of storage time being the most important. The presence or absence of light exerted a negligible impact on the decomposition rate.

Using spectrophotometry and spectral mapping technique for the study of the production of manganese-dependent and manganese-independent peroxidases by Pleurotus ostreatus.

The activity of manganese-dependent and manganese-independent peroxidases produced by Pleurotus ostreatus in culture media composed of agro-residues was measured by visible spectrophotometry. The overall enzyme activity and its selectivity were separated by using spectral mapping technique followed by nonlinear mapping. The relationships between the parameters of enzyme production and the composition of culture media and fermentation time was assessed by stepwise regression analysis. Calculations proved that the addition of extract of straw to the culture media significantly decreased the overall production of both enzymes, whereas the selectivity of enzyme production was influenced by amount of potato extract and the concentration of total sugar in the culture media. Enzyme activity depended quadratically on the fermentation time.