Showing papers by "Universidade Federal de Viçosa published in 2006"

Impacts of drought and temperature stress on coffee physiology and production: a review

Abstract: Overall, drought and unfavourable temperatures are the major climatic limitations for coffee production. These limitations are expected to become increasingly important in several coffee growing regions due to the recognized changes in global climate, and also because coffee cultivation has spread towards marginal lands, where water shortage and unfavourable temperatures constitute major constraints to coffee yield. In this review, we examine the impacts of such limitations on the physiology, and consequently on the production of mainly Coffea arabica and C. canephora, which account for about 99 % of the world coffee bean production. The first section deals with climatic factors and the coffee plant’s requirements. The importance of control ling oxidative stress for the expression of drought and cold tolerance abilities is emphasized in the second section. In the third section, we examine the impacts of drought on cell-water relations, stomatal behaviour and water use, photosynthesis and crop yield, carbon and nitrogen metabolism, root growth and characteristics, and on drought tolerance. In the fourth section, the impacts of low positive and high temperatures on coffee physiology are discussed; some insights about effects of negative temperatures are also presented. Finally, the last section deals with shading in harsh environments as a mean of buffering climatic fluctuations, as well as of increasing environmental sustainability in cof fee exploitation.

Contribuição dos domínios físico, social, psicológico e ambiental para a qualidade de vida global de idosos

Abstract: Este estudo investigou a contribuicao de cada dominio da qualidade de vida (fisico, social, psicologico e ambiental) na qualidade de vida global e em que extensao esses dominios explicam a qualidade de vida global de idosos residentes no municipio de Teixeiras, na Regiao Sudeste do Brasil. Trata-se de um estudo observacional de corte transversal, sendo a amostragem aleatoria estratificada por sexo, uso do Programa Saude da Familia e microarea de saude (n = 211, individuos com idade igual ou superior a 60 anos), representando 14,28% do total de idosos do municipio em estudo. O instrumento utilizado foi o Word Health Organization Quality of Life Instrument Bref (WHOQOL-Bref), proposto pela Organizacao Mundial de Saude, aplicado por um unico entrevistador, devidamente treinado. As analises de regressao linear mostraram que nenhuma das variaveis sociodemograficas interferiu significativamente no dominio global da qualidade de vida, e, entre os quatro dominios, o que mais explicou a qualidade de vida global foi o fisico, seguido do ambiental e do psicologico. O dominio social nao mostrou contribuicao significativa na qualidade de vida global. As possiveis explicacoes para os resultados encontrados foram discutidas.

Body mass index and waist circumference: association with cardiovascular risk factors.

Abstract: OBJETIVO: Determinar a associacao entre indice de massa corporal (IMC) e circunferencia abdominal (CA) com fatores de risco para doencas cardiovasculares. METODOS: Estudou-se 231 servidores da Universidade Federal de Vicosa, sendo 54,1% do sexo masculino (21-76 anos). Analisou-se glicemia de jejum, colesterol total e fracoes, triglicerides, pressao arterial, IMC, CA, relacao cintura-quadril e percentual de gordura corporal. Informacoes sobre tabagismo, ingestao de bebidas alcoolicas e atividade fisica tambem foram obtidas. RESULTADOS: As frequencias de sobrepeso/obesidade foram bastante elevadas, principalmente em mulheres. A obesidade abdominal foi observada em 74% das mulheres e 46,1% dos homens. Os homens apresentaram valores medios e medianos de colesterol total, HDL, triglicerides, IMC e percentual de gordura corporal maiores do que as mulheres (p<0,05). O sedentarismo apresentou-se como fator de risco para obesidade e o tabagismo e o consumo de bebidas alcoolicas foram mais frequentes entre homens e entre eutroficos. A maioria das correlacoes entre indices antropometricos e fatores de risco foram significativas, entretanto apresentaram-se fracas. A CA foi o indicador antropometrico que se correlacionou mais fortemente e com maior numero de variaveis. Observou-se que com o aumento do IMC e da gordura abdominal houve elevacao principalmente da glicemia, dos triglicerides, da pressao arterial e reducao do HDL. A frequencia de sindrome metabolica foi maior no grupo sobrepeso/obesidade e em homens. CONCLUSAO: Neste estudo, a frequencia de fatores de risco cardiovascular aumentou com aumento do IMC e CA.

Arabidopsis and tobacco plants ectopically expressing the soybean antiquitin-like ALDH7 gene display enhanced tolerance to drought, salinity, and oxidative stress

Abstract: Despite extensive studies in eukaryotic aldehyde dehydrogenases, functional information about the ALDH7 antiquitin-like proteins is lacking. A soybean antiquitin homologue gene, designated GmTP55, has been isolated which encodes a dehydrogenase motif-containing 55 kDa protein induced by dehydration and salt stress. GmTP55 is closely related to the stress-induced plant antiquitin-like proteins that belong to the ALDH7 family. Transgenic tobacco (Nicotiana tabacum) and Arabidopsis (Arabidopsis thaliana) plants constitutively expressing GmTP55 have been obtained in order to examine the physiological role of this enzyme under a variety of stress conditions. Ectopic expression of GmTP55 in both Arabidopsis and tobacco conferred tolerance to salinity during germination and to water deficit during plant growth. Under salt stress, the germination efficiency of both transgenic tobacco and Arabidopsis seeds was significantly higher than that of their control counterparts. Likewise, under progressive drought, the transgenic tobacco lines apparently kept the shoot turgidity to a normal level, which contrasted with the leaf wilt phenotype of control plants. The transgenic plants also exhibited an enhanced tolerance to H(2)O(2)- and paraquat-induced oxidative stress. Both GmTP55-expressing Arabidopsis and tobacco seeds germinated efficiently in medium supplemented with H(2)O(2), whereas the germination of control seeds was drastically impaired. Similarly, transgenic tobacco leaf discs treated with paraquat displayed a significant reduction in the necrotic lesions as compared with control leaves. These transgenic lines also exhibited a lower concentration of lipid peroxidation-derived reactive aldehydes under oxidative stress. These results suggest that antiquitin may be involved in adaptive responses mediated by a physiologically relevant detoxification pathway in plants.

Cost and mitigation of insecticide resistance in the maize weevil, Sitophilus zeamais

Abstract: . A common assumption in models of insecticide resistance evolution is the association between resistance and fitness costs in the absence of insecticides. There is empirical evidence of such associations, but their physiological basis (and mitigation) is little investigated. Pyrethroid-resistant populations of the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) offer this opportunity. Pyrethroid resistance in this species was initially observed in five Brazilian states by 1995, but the phenomenon apparently decreased and did not spread to other regions, probably due to the occurrence of a fitness disadvantage in resistant individuals in the absence of insecticides. The present investigation aims to verify whether differences in respiration rate and fat body morphology are related to differences in rate of development in Brazilian populations of S. zeamais resistant to insecticides, and thereby provide evidence for the existence (or not) of a physiological fitness cost acting against insecticide resistance in maize weevils. This may occur due to a possible energy trade-off between insecticide resistance and other physiological processes associated with development and reproduction. To achieve this, studies of the rate of development, respiration and fat body cytomorphology are carried out in one insecticide-susceptible (from Sete Lagoas) and two resistant populations (from Jacarezinho and Juiz de Fora) of S. zeamais. The resistant population from Jacarezinho shows that higher body mass is associated with higher energy reserves (larger trophocyte area) for development and reproduction, as well as for insecticide resistance. However, the resistant population from Juiz de Fora does not appear to have large enough energy allocation for insecticide-resistance expression and development and/or reproductive performance, suggesting a trade-off between resistance and other life history traits.

Caracterização morfométrica da bacia hidrográfica do rio Debossan, Nova Friburgo, RJ

Abstract: The objective of this work was to perform a morphometric characterization based on some physical parameters. In order to do so, a Hydrologically Consistent Digital Elevation Model (HCDEM) was generated from IBGE topographical maps, scale 1:50.000, using as database and analysis the system of geographic information, by means of the ArcVIEW and Arc/INFO version 8.3 systems. From this, some morphometric parameters of a previous study on the hydrologic behavior of the watershed were calculated. The drainage area was 9,9156 Km2 and 17,684 km in perimeter. The Debossan river watershed was proven not easily subject to floods as the compacity coefficient was far from the unit (1.5842) and its shape factor presented a low value (0.3285). Such fact can still be proven by the circularity index value (0.3985). The drainage density was 2,3579 Km/Km2, showing that the watershed has average draining capacity. The drainage system forms a dendritic pattern. This pattern occurs in high lands, in which the regolith and the parent rock relatively provide a uniform resistance to erosion. The more elongated watershed shape, as the circularity index, shape factor and compacity coefficient, indicates that the rainwater volume that falls within the watershed is concentrated in different points, contributing to reduce rain intensities that could cause greater flow variations.

MODIS land cover and LAI collection 4 product quality across nine sites in the western hemisphere

Abstract: Global maps of land cover and leaf area index (LAI) derived from the Moderate Resolution Imaging Spectrometer (MODIS) reflectance data are an important resource in studies of global change, but errors in these must be characterized and well understood. Product validation requires careful scaling from ground and related measurements to a grain commensurate with MODIS products. We present an updated BigFoot project protocol for developing 25-m validation data layers over 49-km2 study areas. Results from comparisons of MODIS and BigFoot land cover and LAI products at nine contrasting sites are reported. In terms of proportional coverage, MODIS and BigFoot land cover were in close agreement at six sites. The largest differences were at low tree cover evergreen needleleaf sites and at an Arctic tundra site where the MODIS product overestimated woody cover proportions. At low leaf biomass sites there was reasonable agreement between MODIS and BigFoot LAI products, but there was not a particular MODIS LAI algorithm pathway that consistently compared most favorably. At high leaf biomass sites, MODIS LAI was generally overpredicted by a significant amount. For evergreen needleleaf sites, LAI seasonality was exaggerated by MODIS. Our results suggest incremental improvement from Collection 3 to Collection 4 MODIS products, with some remaining problems that need to be addressed

Intraguild predation usually does not disrupt biological control

Abstract: Intraguild predation is claimed to be ubiquitous in nature. It also occurs among natural enemies in biological control systems, where one natural enemy (the intraguild predator) attacks another species of natural enemy (the intraguild prey), whereas they also compete for the same pest. We review the theory of intraguild predation and its consequences for biological control for two different scenarios. 1. The intraguild predator is the superior natural enemy ($i.e.$ reduces the pest population the most). In this case, the intraguild predator will exclude the intraguild prey, thus there will be no intraguild predation in the long term. 2. The intraguild prey is the superior natural enemy. In this case, the intraguild predator and intraguild prey may coexist or the intraguild predator can exclude the intraguild prey. Theory predicts for this scenario that pest numbers will always be lowest when only the intraguild prey is present. Hence, the occurrence of intraguild predation in cropping systems would never result in increased control, but can result in decreased control. We subsequently review experimental tests of the effect of intraguild predation among natural enemies on the population dynamics of pests. Contrary to expectations, we find that intraguild predation often did not result in an increase of pest populations, even when the intraguild predator was the inferior natural enemy. Often, the presence of the intraguild predator had no effect or even resulted in a decrease of pest populations. Although the number of studies was limited, we scanned the literature to identify possible causes for the discrepancy of experimental results with theoretical predictions. We specifically evaluated trends in the effects with respect to the length of the study period, the spatial scale at which experiments were carried out, the number of species involved in the studies and the spatial complexity of the experimental arenas. There was a slight trend towards experiments of longer duration showing less positive effects on pest densities, but no clear effect of spatial scale. All studies that showed positive effects on pest densities were studies with 3 species, but the number of studies with more than 3 species was small. Spatial complexity had mixed effects on experimental results. In conclusion, it is clear that intraguild predation most often does not increase pest densities as was predicted from theory, but more research is needed to reveal why theory does not meet practice.

Morfometria da bacia hidrografica da Cachoeira das Pombas, Guanhães - MG

Abstract: RESUMO – O objetivo deste trabalho foi estudar a morfometria da bacia hidrografica da Cachoeira das Pombas, localizada no Municipio de Guanhaes, MG. A base de dados foi disponibilizada pelo convenio SIF/CENIBRA/ UFV e consistiu dos dados matriciais Modelo Digital de Elevacao Hidrologicamente Consistente (MDEHC), rede hidrografica e direcoes de escoamento. As caracteristicas morfometricas e delimitacao da bacia e subbacias hidrograficas foram obtidas automaticamente pelo software Hidrodata 2.0. A area de drenagem encontrada foi de 6,981 km² e o perimetro de 14,864 km. De forma geral, constatou-se que a area estudada possui forma alongada, com baixa densidade de drenagem, relevo forte-ondulado e declividade media de 33,9%. Esses parâmetros possuem grande influencia sobre o escoamento superficial e, consequentemente, sobre o processo de erosao, que resulta em perda de solo, agua, materia orgânica, nutrientes e microfauna, que podem vir a provocar o assoreamento e eutrofizacao dos corpos d´agua. Quanto a orientacao do terreno, pode-se se constatar que 41% do terreno da bacia hidrografica esta exposto a face norte-oeste, e 33% de sua area total encontra-se sombreada. Para um estudo mais detalhado, procuraram-se caracterizar suas sub-bacias, onde cada uma foi analisada individualmente, concluindo-se que as cinco sub-bacias apresentam deficiencia de densidade de drenagem e forma alongada. Em termos de declividade media, os valores variaram entre 29,6 e 40,4%, representando o relevo forte-ondulado. Pode-se constatar, tambem, que a morfometria diferenciada entre as sub-bacias evidencia a necessidade de um manejo especifico de cada uma delas.

Heavy Metal Availability in Soil Amended with Composted Urban Solid Wastes

Abstract: A study was performed to evaluate the pH and the availability of Zn, Cu, Mn, Pb, and Ni in soil amended with increasing doses of composted solid wastes, collected in Rio de Janeiro, Rio de Janeiro State and in Coimbra, Minas Gerais State, Brazil. The influence of the time elapsed between compost application to the soil and the sampling of the plant growth substrate (soil + compost) for pH and metal availability analyses was also examined. The availability of heavy metals in the soil, in the compost and in the substrate was evaluated using DTPA solution for metal extraction. The increase of the compost doses added to the soil resulted in the increase of the pH in the substrate. The addition of the compost from the bigger city, Rio de Janeiro, resulted in higher increase in soil pH and available Zn, Cu, Pb, and Ni levels as compared to the addition of the compost from the smaller city, Coimbra. Increasing the time elapsed between the compost application to the soil and the sampling of the mixture resulted in higher available Zn, Cu, Mn, and Pb levels. The addition of the compost from Rio de Janeiro resulted in substrate metal concentrations in the order Zn > Pb > Ni > Cu > Mn and for the Coimbra compost the metal concentrations in the substrate was Zn > Pb > Cu > Ni > Mn. The higher values of pH and available metals obtained for the bigger city were attributed to the greatest metal contamination of its compost.

Ornithogenic Gelisols (Cryosols) from Maritime Antarctica

Abstract: In terrestrial ecosystems of Maritime Antarctica (King George Island), the transference of primary marine production to the land promoted by penguins (Pygoscelis adeliae) and other birds, appears to influence soil formation and chemical weathering to a greater extent than formerly predicted. This paper summarizes the results of pedological investigations on the vicinity of the American Pieter J. Lenie Field Station (62°10' S, 58°28' W), discussing soil formation processes related to vegetation succession in the studied area. Soil organic matter (SOM) accumulation and associated phosphatization are marked soil-forming processes in ice-free areas once colonized by penguins. Also there is a high correlation between soil development and vegetation patterns. Nutrient supply in these cryogenic soils is affected by low pH following nitrification and high contents of P, K, Ca, and Mg due to seabirds' inputs. Lithic Umbriturbels and Glacic Haploturbels are the most common omithogenic soils, followed by Lithic Fibristels and Psammentic Aquiturbels. In all soils phosphatization and omithogenesis occurs in varying degrees. However, the recent Gelisols order of Soil Taxonomy does not consider the influence of ornithogenesis or phosphatization in its framework, so that a more detailed classification of such soils is not possible.

Qualidade nutricional e escore químico de aminoácidos de diferentes fontes protéicas

Abstract: As proteinas sao moleculas essenciais para aos organismos animais, devendo, portanto, estar presentes na alimentacao em quantidades adequadas. Alem do aspecto quantitativo deve-se levar em conta o aspecto qualitativo, isto e, seu valor nutricional, que dependera de sua composicao, digestibilidade, biodisponibilidade de aminoacidos essenciais, ausencia de toxicidade e de fatores antinutricionais. O objetivo deste trabalho foi avaliar a digestibilidade in vivo, o escore quimico de aminoacidos (EQ) e o escore quimico de aminoacido corrigido pela digestibilidade proteica (PDCAAS) das seguintes fontes de proteina: carne de ra sem osso, carne de ra com osso, carne de ra mecanicamente separada (CMS), carne bovina, ovo em po, caseina, trigo, milho, soja convencional, soja isenta de inibidor de tripsina Kunitz e de lipoxigenases (soja KTI-LOX-), proteina texturizada de soja (PTS) e feijao. As proteinas de origem animal apresentaram maiores valores de digestibilidade que as de origem vegetal. Carne de ra sem osso apresentou a proteina com maior digestibilidade proteica de todas as proteinas estudadas, nao diferindo, entretanto, da caseina, CMS, carne bovina e ra com osso. Das proteinas de origem animal, a do ovo em po foi aquela que apresentou menor digestibilidade proteica. Nenhuma das proteinas de origem animal apresentou aminoacidos essenciais limitantes quando comparadas com o padrao da FAO/WHO. Feijao, soja convencional, soja KTI-LOX- e PTS, tiveram os aminoacidos sulfurados (metionina+cisteina) como limitantes. Enquanto que para trigo e milho, o aminoacido mais limitante foi a lisina. Soja KTI-LOX- e PTS apresentaram valores de PDCAAS superiores aos da soja convencional, mostrando uma possivel elevacao na qualidade proteica da soja melhorada geneticamente e da soja processada.

Efeito de diferentes substratos sobre o desenvolvimento de mudas de Acacia sp.

Abstract: Sewage sludge has been studied as source of organic matter on seedling production. Thus, this study aimed to evaluate the development of Acacia mangium and Acacia auriculiformis seedlings in the following substrates: a) oxic horizon + sand (1:1, v:v) + 160, 640 e 160 g m-3 of N, P2O5 and K2O respectively (HB); b) oxic horizon + sand + cattle manure (1:1:1, v:v) (HBE); c) oxic horizon + sand + sewage sludge (1:1:1, v:v) (HBL) and; d) 100% sewage sludge (LE). The substrates were limed with 1 kg m-3CaCO3 p.a.. Seeds, inoculated and non-inoculated with Rhizobium, were used, and 90 days after planting, measures of collar diameter, plant height, and root and shoot dry matter (with determination of N, P, K, Ca and Mg) were taken. The experimental design was completely randomized blocks, in a factorial 2 x 4 arrangement (with or without inoculation x 4 substrates). Better performance in seedling growth was obtained in the LE substrate with inoculated seeds. Comparatively, the HBE substrate was superior to the HBL substrate. There were no significant differences for most evaluated parameters in the HBE, HBL and HB substrates due to inoculation, probably because the existence of native bacteria in these substrates. The seedlings developing in the LE substrate accumulated more N and Ca, mainly when inoculated. There was a tendency of larger P, K and Mg accumulation in shoots of seedlings developing in the HBE substrate.

Características morfogênicas e estruturais do capim-braquiária em pastagem adubada com nitrogênio avaliadas nas quatro estações do ano

Abstract: Este experimento foi realizado com o objetivo de avaliar o efeito da adubacao nitrogenada sobre as caracteristicas morfogenicas e estruturais de Brachiaria decumbens sob pastejo. Os tratamentos consistiram da aplicacao de quatro doses de nitrogenio (75, 150, 225 e 300 kg/ha.ano) antes do inicio das avaliacoes experimentais, realizadas em 2002 durante as estacoes de verao, outono, inverno e primavera. Utilizou-se o delineamento em blocos completos casualizados, com duas repeticoes. A taxa de alongamento de folha, o comprimento final da folha, o indice de area foliar e as porcentagens de colmo e de lâmina foliar aumentaram linearmente, enquanto a porcentagem de material morto decresceu com a adubacao nitrogenada da Brachiaria decumbens sob pastejo. Nao foi constatado efeito da adubacao nitrogenada sobre o numero de folhas vivas, de folhas emergentes e de folhas totais e as taxas de alongamento do colmo e de senescencia foliar. A taxa de alongamento de folha e de colmo, o numero de folhas vivas, o comprimento final da folha, o indice de area foliar e a porcentagem de lâmina foliar e de colmo de Brachiaria decumbens variaram entre estacoes do ano, apresentando valores menores no inverno.

Estimating the effects of population size and type on the accuracy of genetic maps

Abstract: Based on simulation studies, it was shown that the type and size of experimental populations can exert an influenceon the accuracy of genetic maps. A hypothetical genome map (one chromosome with nine equidistant molecularmarkers) was generated for the following population types: F 2 with dominant and co-dominant markers, backcross-ing, recombinant inbred lines (RIL) and double-haploid. The population sizes were 50, 100, 150, 200, 500 and 1000individuals and 100 simulations were made for each population. The inaccuracies of the populations with the lowestnumber of individuals were shown by inversions in the order of the markers and the establishment of more than onelinkage group in up to 38% of the simulations, depending on the population type. Stress and variance values of thedistancesbetweenadjacentmarkersweresignificantlyreducedwiththeincreasedsizeofthepopulation.Moreaccu-rate maps were obtained for the co-dominant F 2 and RIL whereas the maps for the dominant F 2 population were lessaccurate. The higher the number of individuals, the more precise was the map. In all populations, a total of 200 indi-viduals were considered as being sufficient for the construction of reasonably accurate genetic maps. Although thispaper deals with plant populations this approach is equally applicable to other organisms.

Seasonal abundance and sexual variation in morphometric traits of Oxelytrum discicolle (Brulle, 1840) (Coleoptera: Silphidae) in a Brazilian Atlantic Forest

Abstract: Ferreira, P.S.F.; Pires, E.M.; Guedes, R;N.C.; Mendes, M. and Coelho, L.A. Seasonal abundance and sexual variation in morphometric traits of Oxelytrum discicolle (Brulle, 1840) (Coleoptera: Silphidae) in a Brazilian Atlantic Forest. Biota Neotrop. May/Aug 2006, vol. 6, no. 2, http://www.biotaneotropica.org.br/v6n2/pt/abstract?article+bn02206022006. ISSN 1676-0611 A total of 293 specimens of Oxelytrum discicolle were sampled weekly over a period of two years using a black light trap. The study took place in an Atlantic Forest reserve located near Vicosa city, Minas Gerais State, Brazil. The period of peak abundance of O. discicolle occurred during the wet season between the months of October and March. Statistical analysis showed that the abundance of individuals was significantly and positively correlated with temperature, but not with rainfall or relative humidity. Of 28 morphological measurements taken on each collected specimen, seven were found to be sexually dimorphic; however, neither morphology nor the degree of sexual dimorphism varied significantly among seasons.

Responses of restinga plant species to pollution from an iron pelletization factory

Abstract: shape Byrsonima sericea DC. (Malpighiaceae), shape Cordia verbenacea DC. (Boraginaceae) and shape Psidium guineense SW. (Myrtaceae) were studied in two experimental sites: a restinga forest fragment, near an iron pelletization factory (mining area) and a restinga conservation unit “Paulo Cesar Vinha State Park”. The aims were verify the effects of emissions from a pelletization factory on some anatomical and physiological parameters and on absorption and accumulation of particulate iron by the leaves. A protocol was adjusted using Prussian blue reaction to histochemical detection of iron. Comparing the same species in two locals, shape C. verbenacea was the greatest accumulator of metallic iron, whereas shape B. sericea presented greater content of sulphur in mining area. The greater leaf contents of metallic iron may be related to the adhesion of the particles deposited on the leaves and to the characteristics of the covering tissue and the leaf. The foliar parameters evaluated in addition to soil analysis and atmospheric precipitation data indicated that the effects of particulate deposition occurred due foliar uptake. Structural characteristics such as peltate trichomes of leaf abaxial surface in shape B. sericea and hypodermis observed in shape B. sericea (one layer) and shape P. guineense (3--4 layers), probably formed a barrier lessening the penetration of metallic iron into the mesophyll as evidenced by the lower iron leaf content and iron accumulation in trichomes observed in these two species. In leaves of shape C. verbenacea occurred a positive reaction for iron in trichomes, epidermic cells at both faces, stomata, some xylem cells, collenchyma and endodermis at the midrib, and mesophyll tissues. The obtained data indicated that the unit conservation is also under pollution impact.

Characterization and genetic diversity analysis of cotton cultivars using microsatellites

Abstract: Genetic diversity and the relationship between varieties are of great importance for cotton breeding. Our work was designed to estimate the informativeness of the cotton (Gossypium hirsutum L.) simple sequence repeat (SSR) microsatellite locus and to estimate the genetic distance between 53 cotton cultivars as well as to select a set of SSR primers able to differentiate between the 53 cotton cultivars studied. After extracting DNA from the 53 cultivars and characterized it using 31 pairs of SSR primers we obtained a total of 66 alleles with an average of 2.13 alleles per SSR locus and values of polymorphism information content (PIC) varying from 0.18 to 0.62, the dissimilarity coefficient varying from zero to 0.41. Statistical analysis using the unweighted pair-group method using arithmetic average (UPGMA) revealed seven subgroups which were consistent with the genealogical information available for some of the cultivars. The SSR genetic profile obtained for each of the cultivars made it possible to discriminate 52 of the 53 cultivars. This study of the genetic diversity of cotton cultivars with SSR markers support the need to introduce new alleles into the gene pool of the breeding cultivars.

Development and evaluation of an edible antimicrobial film based on yam starch and chitosan

Abstract: Edible antimicrobial films are an innovation within the biodegradable active packaging concept. They have been developed in order to reduce and/or inhibit the growth of microorganisms on the surface of foods. This study developed an edible antimicrobial film based on yam starch (Dioscorea alata) and chitosan and investigated its antimicrobial efficiency on Salmonella enteritidis. A solution of yam starch (4%) and glycerol (2%) was gelatinized in a viscoamilograph and chitosan added at concentrations of 1%, 3% and 5%. Films with and without chitosan were produced by the cast method. To evaluate the antimicrobial activity of the films, two suspensions of S. enteritidis were used in BHI medium, corresponding to counts of 2 × 108 and 1.1 × 106 CFU/ml. The suspensions (50 ml) were poured into flasks. The films were cut into 5 × 5 and 5 × 10 cm rectangles to be used at ratios of 1 : 1 (1 cm2/ml microorganism suspension) and 2 : 1 (2 cm2/ml). The film 30 µm thick on average. As a control, pure chitosan at an amount corresponding to that contained in the 3% and 5% films (5 × 10 cm) was added to flasks containing the microorganism suspension. Also, flasks containing only a suspension of S. enteritidis were used as control. The suspensions, in flasks, were kept at 37°C in a waterbath with agitation. Suspension aliquots were removed every hour for reading the optic density (OD595) and plating onto PCA medium. The results showed that chitosan has a bactericidal effect upon S. enteritidis. Films treated with chitosan at different concentrations showed similar antimicrobial efficiency, in addition to being dependent on diffusion. The chitosan-treated films caused a reduction of one to two log cycles in the number of microorganisms, whereas the pure chitosan presented a reduction of four to six log cycles compared with the control and starch film. The films showed good flexibility. Copyright © 2005 John Wiley & Sons, Ltd.

Qualidade microbiológica de leite cru refrigerado e isolamento de bactérias psicrotróficas proteolíticas

Abstract: Storing refrigerated raw milk in the source of production reduces economic losses which occur due to the acidifying activity of mesophilic bacteria. Nevertheless, this process selects psychrotrophic bacteria that cause technological and economic problems to the dairy industry. Samples of individual and collective refrigerated tanks and samples from an industrial silo in a dairy industry were collected and analyzed to evaluate the microbiological quality of raw milk. Furthermore, proteolytic psychrotrophic bacteria were isolated from refrigerated raw milk and characterized according to the Gram reaction and glucose fermentation. The refrigerated raw milk from the industrial silo was not compatible with legal microbiological standards, and its microbial count was significantly higher than milk from individual and collective tanks. A significant difference of contamination by mesophiles, proteolytic and non-proteolytic psychrotrophs, and Pseudomonas was observed in samples collected from refrigeration tanks compared to samples collected from the industrial silo. The Gram-negative microbiota was isolated more often, especially the glucose non-fermentative Gram-negative bacteria.

Cowpea aphid-borne mosaic virus (CABMV) is widespread in passionfruit in Brazil and causes passionfruit woodiness disease

Abstract: Leaf samples of yellow passionfruit (Passiflora edulis f. flavicarpa) displaying fruit woodiness symptoms were collected in seven Brazilian states and the Federal District. Viral infection was confirmed by host range and ELISA, and fourteen viral isolates were obtained. All isolates were capable of infecting several leguminous host species, although differences in symptom severity were noticeable. Woodiness symptoms were reproduced in yellow passionfruit, and mosaic symptoms were induced in common bean. All isolates infected cowpea, reported as a non-host of passion fruit woodiness virus (PWV). Indirect ELISA demonstrated that all isolates were serologically related to each other and also to cowpea aphid-borne mosaic virus (CABMV). The complete sequence of the capsid protein was determined for all isolates. Comparison of these sequences with those of other potyviruses indicated the highest identity with CABMV isolates (85 to 94%). Identity with PWV isolates ranged from 54 to 70%. Phylogenetic analysis grouped all of the Brazilian isolates in a monophyletic cluster with the CABMV isolates, clearly distinct from the PWV isolates. Furthermore, this analysis demonstrated that a group of previously characterized isolates from Brazil that had been designated as PWV should be reclassified as CABMV. Together, these results provide unequivocal evidence that, in Brazil, passionfruit woodiness disease is primarily caused by CABMV. The presence of PWV in Brazil has yet to be confirmed.

Clay-sized minerals in permafrost-affected soils (cryosols) from king george island, antarctica

Abstract: Cryosols from Maritime Antarctica have been less studied than soils from continental areas of Antarctica. In this work X-ray diffraction, difference X-ray diffraction, differential thermal analysis, thermogravimetry, transmission electron microscopy/energy dispersive spectroscopy and selective chemical dissolution were used to characterize the clay fraction of basaltic, acid sulfate and ornithogenic Cryosols from ice-free areas of Admiralty Bay, King George Island. Non-crystalline phases are important soil components and reach >75% of the clay fraction for some ornithogenic soils. Randomly interstratified smectite-hydroxy-Al-interlayered smectite is the main clay mineral of basaltic soils. Kaolinite, chlorite and regularly interstratified illite-smectite predominate in acid sulfate soils. Jarosite is also an important component of the clay fraction in these soils. Crystalline Al and Fe phosphates occur in the clay at sites directly affected by penguin activity and the chemical characteristics of these ornithogenic sites are controlled by highly reactive, non-crystalline Al, Si, Fe and P phases. Chemical weathering is an active process in Cryosols in Maritime Antarctica and is enhanced by the presence of sulfides for some parent materials, and faunal activity.

A PERK-like receptor kinase interacts with the geminivirus nuclear shuttle protein and potentiates viral infection.

Abstract: The nuclear shuttle protein (NSP) from bipartite geminiviruses facilitates the intracellular transport of viral DNA from the nucleus to the cytoplasm and acts in concert with the movement protein (MP) to promote the cell-to-cell spread of the viral DNA. A proline-rich extensin-like receptor protein kinase (PERK) was found to interact specifically with NSP of Cabbage leaf curl virus (CaLCuV) and of tomato-infecting geminiviruses through a yeast two-hybrid screening. The PERK-like protein, which we designated NsAK (for NSP-associated kinase), is structurally organized into a proline-rich N-terminal domain, followed by a transmembrane segment and a C-terminal serine/threonine kinase domain. The viral protein interacted stably with defective versions of the NsAK kinase domain, but not with the potentially active enzyme, in an in vitro binding assay. In vitro-translated NsAK enhanced the phosphorylation level of NSP, indicating that NSP functions as a substrate for NsAK. These results demonstrate that NsAK is an authentic serine/threonine kinase and suggest a functional link for NSP-NsAK complex formation. This interpretation was corroborated by in vivo infectivity assays showing that loss of NsAK function reduces the efficiency of CaLCuV infection and attenuates symptom development. Our data implicate NsAK as a positive contributor to geminivirus infection and suggest it may regulate NSP function.