Homero Dewes

Functional bovine immunoglobulins in Boophilus microplus hemolymph

The aim of the present work was to quantify the passage of bovine immunoglobulins into the hemolymph of the tick Boophilus microplus during the feeding process and to determine their antibody activity. The knowledge is of paramount importance when vector control or blocking of disease transmission is attempted by vaccination of cattle. Approximately 2% of bovine immunoglobulin present in the serum as determined by competitive ELISA was demonstrated in hemolymph of B. microplus and antibody activity against an antigen of B. microplus in the hemolymph of ticks fed on bovine immunized with the antigen purified from tick eggs was detected by Western blot assay. The antibody reactivity detected against the B. microplus antigen showed that functional antibodies are present in the hemolymph of fully engorged ticks for at least 48 h after completing the parasitic life cycle.

Purification and characterization of β-N-acetylhexosaminidase from bovine tick Boophilus microplus (Ixodide) larvae

beta-N-Acetylhexosaminidase (HEX, E.C. 3.2.1.52) from larvae of the ixodid tick Boophilus microplus was purified to capillary zone electrophoresis homogeneity, and characterized. Enzyme purification was carried out by sequential liquid chromatography on Sephadex G-200, p-aminobenzyl-N-acetyl-beta-D-thioglucosamine affinity, and Mono-Q FPLC columns. Purification was about 1600-fold, with a yield of 10%, as determined with p-nitrophenyl-N-acetylglucosaminide as substrate. The enzyme presented optimum pH 4.7, and optimum temperature 65 degrees C. The molecular weight of non-denatured enzyme was estimated as 127,000 by gel filtration chromatography, and 60,000 in SDS-PAGE. The tick hexosaminidase presented glycosyl residues, as evidenced by binding to Concanavalin-A. Among several p-nitrophenyl glycosides tested as substrate, HEX was active only on p-nitrophenyl-N-acetylglucosaminide and p-nitrophenyl-N-acetylgalactosaminide. The purified enzyme presented immunogenicity in rabbit, and the correspondent antibodies inhibited about 90% of its original, in vitro activity.

A putative RNA virus in Babesia bovis

Babesia bovis is an intraerythrocytic protozoan that causes bovine babesiosis. Agarose gel electrophoresis of nucleic acids extracted from two isolates of B. bovis reveals, besides bulk DNA, an ethidium bromide-stainable band at about 5.5 kb. Further characterization of the latter with DNase I, RNase and mung bean nuclease suggested it to be a double-stranded RNA. Sonicated parasites were fractionated in a CsCl buoyant density gradient. A sample containing the 5.5-kb RNA was analysed under an electron microscope and a virus-like particle was observed.

Effect of antibodies against β-N-acetylhexosaminidase on reproductive efficiency of the bovine tick Boophilus microplus

A polyclonal antibody (anti-HEX) was developed against a soluble N-acetylhexosaminidase (HEX) isolated from larval extracts of Boophilus microplus. Purified hexosaminidase was strongly inhibited by the IgG fraction of this antibody. The antibody inhibited the hexosaminidase activity of other sources, such as haemolymph and larval membranes. The antibody reacted with different antigens in the tick haemolymph, but did not recognize any antigen in saliva, as seen by immunoblot analysis. The anti-HEX was inoculated into fully engorged B. microplus females, resulting in a decrease in oviposition of approximately 26%, relative to the effect of pre-immune IgG. These data show the potential of the use of this tick enzyme as an antigen in vaccine development.

The macro-environment for liquid Biofuels in Brazilian science and public policies

The purpose of this study is to identify the macro-environmental dimensions through which Brazilian scientists and government officials have framed issues surrounding liquid biofuels over a period of time. This study analyzes scientific papers published by researchers affiliated with Brazilian institutions and official documents of the Brazilian government related to liquid biofuels. Documents published during a ten-year period (1997--2006) were collected from electronic sources. Text-mining procedures were applied through a framework of macro-environmental dimensions and their corresponding d-words in order to extract high-quality content. Results indicate that the macro-environment developed by Brazilian scientists differs from the one created by the government. Variations in describing macro-environmental dimensions existed for both the Brazilian government and for scientists during the period of analysis. Similarity tests reveal significant differences between the scientific documents and the government documents, indicating that Brazilian public policy regarding liquid biofuels is dissociated from the scientific findings of Brazilian researchers. Copyright The Author 2012. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com, Oxford University Press.

Organic products in Brazil: from an ideological orientation to a market choice

Purpose – The purpose of this paper is to analyse the evolution of the production and commercialisation of organic products in Brazil since 1980. Design/methodology/approach – The literature review in this study assesses scientific papers, studies conducted by Brazilian and international institutions, and trade news related to the evolution of the production and commercialisation of organic products. The analysis is based on theories of consumer behaviour and competitive strategies. Findings – The results provide evidence that the organic food market in Brazil was initially based on social ideology and a movement that was opposed to conventional farming; however, since 1980, the supply and demand patterns have changed. The commercialisation of organic products since the turn of the decade has expanded beyond ideological motivation and into the Brazilian agribusiness sector. The main reasons for this expansion are changes in preferences by the Brazilian consumer, a substantial number of whom have become mo...

Food insecurity worldwide derived from food supply patterns

Worldwide, humanity is facing severe nutritional imbalances, which are dependent on access to food and the dietary habits of particular populations that can make them susceptible to malnutrition. This study aims to identify and analyze the main food supply patterns (FSPs) of populations worldwide, and then to relate them to their respective malnutrition conditions. The hypothesis is that there are specific, geographically identifiable FSPs that are associated with the nutritional misalignment of certain populations to a greater degree than others. This investigation is based on data regarding the supply of the main food groups worldwide, as well as the metrics associated with malnutrition. Data analyses were performed using descriptive statistics, cluster analysis, ANOVA, and correlation analysis. The results suggest the existence of nine clusters of countries with specific FSPs that differ significantly regarding their supplies of macronutrients and their malnutrition traits. Furthermore, using Pearson’s coefficient of variation (CV) to assess the balance level (or symmetry) of each FSP, reflecting the average supply of food groups, the results suggest the existence of a positive and significant correlation (r = 0.6364; p = 0.000) between the imbalance level of particular FSPs and the prevalence of underweight children in their respective populations. Also, FSPs 1, 3, and 4 are strongly associated with obesogenic traits, with FSP 3 being the most strongly associated with the prevalence of overweight. According to our analyses, the FSPs of Southern Africa (with a strong prevalence of child overweight) and Southern Asia (with a strong prevalence of child underweight) lead to the worst conditions observed, while the populations with the best nutritional status are based on the FSP of Eastern Asia.

Food away from home and obesity in Brazil

Purpose - – The purpose of this paper is to characterize food consumption outside the home and verify the existence of relationships between income, expenditure and the prevalence of overweight and obesity in adult individuals in Brazil. Design/methodology/approach - – Food expenditure data were used as well as those on the prevalence of overweight and obesity available in the reports from Family Budgets Research carried out by the Brazilian Institute of Geography and Statistics (IBGE) in the years 2002-2003 and 2008-2009. In addition, the authors used the Kruskall-Wallis test to verify whether there were significant differences between the classes of income with respect to the average expenditure on food outside the home. Findings - – It was observed that the higher the income of the individual, the greater the expenditure on food outside the home. It was also found that the prevalence of overweight and obesity is higher in individuals who have higher income, particularly among men. Thus, it is suggested that the higher the income of the individual, the larger the expenditure on food outside the home and the greater the prevalence of overweight and obesity. Research limitations/implications - – This study used spending on food away from home (FAFH), but the authors know that is need to use other variables like frequency of FAFH and quantities but this data were not available. Practical implications - – The study points to the importance of restaurants in the prevention of obesity, since they can offer in their menus foods with fewer calories, and they can also increase the variety and availability of fruits and vegetables. Originality/value - – The study discusses the public health problem, obesity, at the same time as it presents the importance of agribusiness in providing a balanced diet for individuals.

Scanning the macro-environment for liquid biofuels: A comparative analysis from public pocies in Brazil, United States and Germany

– Macro‐environmental scanning is a first step in strategic planning, which is essential in an emerging industry such as liquid biofuels. The purpose of this paper is to identify the dimensions within which the governments of Brazil, the USA and Germany have constructed the macro‐environment for liquid biofuels over time and to test for similarities between the governments’ constructs., – Documentary research was carried out on official public policies and program documents on the topic of liquid biofuels, covering a ten‐year period from 1997 to 2006. The database consisted of 624 documents from the Brazilian government, 854 from the American government and 168 documents from the German government. Text mining was used to extract information from the texts by applying a specific analysis structure that was built on macro‐environmental dimensions as expressed by their respective dimensional words “d‐words”. The “d‐words” were selected based on their usage frequency in the knowledge fields related to each dimension., – The results indicate that the macro‐environments for liquid biofuels, as configured by the governments under analysis, differ systematically and over time in their emphasis of specific macro‐environmental dimensions., – There are two primary aspects of this study which are original and valuable: the application of text‐mining techniques as a tool for strategic planning and the development of a particular tool to extract knowledge from text documents and to categorize them according to their macro‐environmental dimensions.

Disciplinary dimensions and social relevance in the scientific communications on biofuels

The disciplinary structure of research on complex problems related to human activities is supported by the fundaments of the social, life, and hard sciences. In this work, we looked at the development of scientific research in the field of biofuels, as a sustainable source of energy, searching for references regarding its scientific roots and social relevance. Scientific communications on biofuels published between 1998 and 2007 were analyzed using a combination of bibliometric methods and text mining techniques. This field of research was characterized as interdisciplinary, with marked social relevance. Our bibliometric analysis shows that, in this research subject, 132 different, interacting fields of knowledge overlap, with dominance of Chemistry, Engineering and Agricultural Sciences. Through the use of text mining techniques, this field was configured into three groups of Disciplinary Dimensions. The first and most influential group includes the Agricultural Sciences, Social Sciences, and Environmental Sciences. The second group, which gives the field its technological basis, includes Chemistry, Engineering, and Microbiology. The third group includes disciplines with emerging involvement in the field of biofuels: Biology and Biochemistry, Animal and Plant Sciences, Molecular Biology and Genetics, Economics, Material Sciences, Nanosciences and Nanotechnology, Geosciences, Physics, Humanities, Multidisciplinary Sciences, Mathematics, and Computer Sciences. This study suggests that the first group of Disciplinary Dimensions conforms to the elements that socially validate the progress of research in the field of biofuels. This study also proposes a metric that can be used to measure the interdisciplinarity and the social framing of any other research field.