Influence of interleukin 1 beta and tumour necrosis factor alpha on the in vitro growth, maturation and mitochondrial distribution of bovine oocytes from small antral follicles.

SummaryThis study aimed to investigate the effects of IL1ß and TNFα on growth and maturation of oocytes from small follicles (1-3 mm) during in vitro culture. To this end, cumulus-oocyte complexes (COCs) with diameters of ~110 µm were cultured in TCM-199 medium alone or supplemented with IL1ß (10 ng/ml), TNFα (10 ng/ml) or both for 48 h. The oocytes were measured at the beginning and at the end of the culture period. COCs were cultured for 20 h in pre-maturation medium and then half of the COCs of each group was destined for in vitro maturation and the remaining COCs were used to evaluate meiotic progression, mitochondrial distribution and the expression of mRNAs for GDF-9, c-Mos, Cyclin-B1 and H1foo. The results showed that COCs cultured with TNFα alone or together with IL1ß had higher diameters than those cultured in control medium alone or supplemented with IL1ß. Control oocytes isolated from large antral follicles (>5 mm) had heterogeneous distribution of mitochondria. Oocytes isolated from small antral follicles, that had been grown in vitro in TCM-199 alone or supplemented with TNFα had similar heterogeneous mitochondrial distribution before in vitro maturation (IVM). After IVM, mitochondria were heterogeneously distribution when cultured in TCM-199. However, when cultured with TNFα and/or IL1ß, mitochondria were homogeneously distributed. Presence of TNFα and/or IL1ß in TCM-199 culture medium did not influence the expression of mRNAs for GDF-9, c-Mos, Cyclin-B1 and H1foo. In conclusion, TNFα and a mixture of TNFα and IL1ß both stimulated the growth of bovine oocytes during their in vitro culture, but do not influence gene expression in grown oocytes.

Sugarcane silage treated with calcium hydroxide in feedlot cattle diet: animal performance and meat quality / Desempenho e qualidade da carne de novilhos confinados alimentados com silagem de cana-de-açúcar tratada com hidróxido de cálcio

Este estudo teve como objetivo avaliar silagem de cana-de-açúcar (Saccharum officinarum L) tratada com hidróxido de cálcio - Ca(OH)2 - (cal hidratada) como único volumoso em ração para confinamento de gado de corte, com respeito ao desempenho e qualidade da carne dos animais. Quarenta e cinco novilhos Canchim (22 meses de idade, 345 kg de peso vivo- PV) foram distribuídos, em um delineamento em blocos casualizados, em três tratamentos (rações totais - RTs - com 35% de volumoso): T1 - RT com cana-de-açúcar fresca; T2 - RT com silagem de cana-de-açúcar tratada com hidróxido de cálcio (10 g Ca(OH)2/kg de forragem fresca); T3 - RT com silagem de milho. Foram avaliados o consumo de matéria seca (CMS), consumo de MS digestível (CMSD), consumo de proteína bruta (CPB), eficiência alimentar (EA), ganho médio diário (GMD) e rendimento de carcaça (RC). A carne foi avaliada quanto a parâmetros de qualidade (pH, capacidade de retenção de água, perdas no cozimento, cor e força de cisalhamento) e de análise sensorial descritiva. Os novilhos alimentados com a silagem de cana-de-açúcar tratada com hidróxido de cálcio apresentaram similares (P>0.05) CMS (10,8 kg/d), CMSD (8,5 kg/d) e RC (52,6%); mais alto (P0.05) (1,5 kg PV/d e 0,15 kg PV/kg CMS, respectivamente). As diferentes rações não afetaram (P>0.05) os parâmetros de qualidade e os atributos sensoriais da carne, com exceção da cor da gordura e sabor estranho na carne. Concluiu-se que o hidróxido de cálcio pode ser indicado como um eficiente aditivo para...

This study aimed to evaluate sugarcane (Saccharum officinarum L) silage treated with calcium hydroxide - Ca(OH)2 - (slacked lime) as the only roughage source in a feedlot ration, regarding animal performance and meat quality. Forty five Canchim steers (22 months old, 345 kg body weight - BW) were assigned, in a complete randomized block design, to three treatments (total mixed rations - TMRs - with 35% roughage): T1- TMR with fresh sugarcane; T2 - TMR with sugarcane silage treated with calcium hydroxide (10 g Ca(OH)2/kg of fresh forage); T3 - TMR with corn silage. Dry matter intake (DMI), digestible DM intake (DDMI), crude protein intake (CPI), feed efficiency (FE), average daily gain (ADG) and dressing percentage (DP) were evaluated. Meat was analyzed for quality parameters (pH, water holding capacity, cooking loss, color and shear force) and sensory attributes. Steers fed the silage treated with calcium hydroxide presented similar (P>0.05) DMI (10.8 kg DM/d), DDMI (8.5 kg/d) and DP (52.6%); higher CPI (1.8 vs. 1.4 kg/d) and lower (P0.05) ADG and FE (1.5 kg BW/d and 0.15 kg BW/kg DMI, respectively). The different rations did not affect (P>0.05) meat quality parameters and sensory attributes, except for fat color and off flavor sensory attribute. It was concluded that calcium hydroxide can be indicated as an efficient additive for sugarcane ensilage. Feedlot cattle fed TMR containing sugarcane silage treated with Ca (OH)2, as the only roughage source, presented adequate performance and meat quality.

Sugarcane silage treated with calcium hydroxide in feedlot cattle diet: animal performance and meat quality / Desempenho e qualidade da carne de novilhos confinados alimentados com silagem de cana-de-açúcar tratada com hidróxido de cálcio

Este estudo teve como objetivo avaliar silagem de cana-de-açúcar (Saccharum officinarum L) tratada com hidróxido de cálcio - Ca(OH)2 - (cal hidratada) como único volumoso em ração para confinamento de gado de corte, com respeito ao desempenho e qualidade da carne dos animais. Quarenta e cinco novilhos Canchim (22 meses de idade, 345 kg de peso vivo- PV) foram distribuídos, em um delineamento em blocos casualizados, em três tratamentos (rações totais - RTs - com 35% de volumoso): T1 - RT com cana-de-açúcar fresca; T2 - RT com silagem de cana-de-açúcar tratada com hidróxido de cálcio (10 g Ca(OH)2/kg de forragem fresca); T3 - RT com silagem de milho. Foram avaliados o consumo de matéria seca (CMS), consumo de MS digestível (CMSD), consumo de proteína bruta (CPB), eficiência alimentar (EA), ganho médio diário (GMD) e rendimento de carcaça (RC). A carne foi avaliada quanto a parâmetros de qualidade (pH, capacidade de retenção de água, perdas no cozimento, cor e força de cisalhamento) e de análise sensorial descritiva. Os novilhos alimentados com a silagem de cana-de-açúcar tratada com hidróxido de cálcio apresentaram similares (P>0.05) CMS (10,8 kg/d), CMSD (8,5 kg/d) e RC (52,6%); mais alto (P<0.05) CPB (1,8 vs. 1,4 kg/d) e menor (P<0.05) GMD (1,58 vs. 1,81 kg PV/d) comparados aos que receberam silagem de milho. Comparados aos animais alimentados com cana-de-açúcar fresca, os novilhos alimentados com silagem de cana-de-açúcar tratada com hidróxido de cálcio apresentaram maior (P<0.05) CMS (10,9 vs. 9,4 kg MS/d), CMSD (8,70 vs. 7,4 kg/d), CPB (1,8 vs. 1,1 kg/d) e RC (52,7 vs. 51,2%), mas o GMD e EA foram similares (P>0.05) (1,5 kg PV/d e 0,15 kg PV/kg CMS, respectivamente). As diferentes rações não afetaram (P>0.05) os parâmetros de qualidade e os atributos sensoriais da carne, com exceção da cor da gordura e sabor estranho na carne. Concluiu-se que o hidróxido de cálcio pode ser indicado como um eficiente aditivo para...(AU)

This study aimed to evaluate sugarcane (Saccharum officinarum L) silage treated with calcium hydroxide - Ca(OH)2 - (slacked lime) as the only roughage source in a feedlot ration, regarding animal performance and meat quality. Forty five Canchim steers (22 months old, 345 kg body weight - BW) were assigned, in a complete randomized block design, to three treatments (total mixed rations - TMRs - with 35% roughage): T1- TMR with fresh sugarcane; T2 - TMR with sugarcane silage treated with calcium hydroxide (10 g Ca(OH)2/kg of fresh forage); T3 - TMR with corn silage. Dry matter intake (DMI), digestible DM intake (DDMI), crude protein intake (CPI), feed efficiency (FE), average daily gain (ADG) and dressing percentage (DP) were evaluated. Meat was analyzed for quality parameters (pH, water holding capacity, cooking loss, color and shear force) and sensory attributes. Steers fed the silage treated with calcium hydroxide presented similar (P>0.05) DMI (10.8 kg DM/d), DDMI (8.5 kg/d) and DP (52.6%); higher CPI (1.8 vs. 1.4 kg/d) and lower (P<0.05) ADG (1.58 vs. 1.81 kg BW/d) and FE (0.15 vs. 0.17 kg BW/kg DMI) in comparison to those receiving corn silage. Compared to animals fed the fresh sugarcane, steers fed sugarcane silage treated with calcium hydroxide presented higher (P<0.05) DMI (10.9 vs. 9.4 kg DM/d), DDMI (8.7 vs. 7.4 kg/d), CPI (1.8 vs. 1.1 kg/d) and DP (52.7% vs. 51.2%) but similar (P>0.05) ADG and FE (1.5 kg BW/d and 0.15 kg BW/kg DMI, respectively). The different rations did not affect (P>0.05) meat quality parameters and sensory attributes, except for fat color and off flavor sensory attribute. It was concluded that calcium hydroxide can be indicated as an efficient additive for sugarcane ensilage. Feedlot cattle fed TMR containing sugarcane silage treated with Ca (OH)2, as the only roughage source, presented adequate performance and meat quality.(AU)

Chemical composition, fermentation profile and apparent digestibility of sugarcane silage treated with chemical additives / Composição química, perfil fermentativo e digestabilidade aparente de silagens de cana-de-açúcar tratadas com aditivos químicos

The aim of this study was the indication of an additive for the ensilage of sugarcane (Saccharum officinarum L.). In a laboratory trial, nine treatments were applied (g of additive/kg of fresh forage - FF) to the sugarcane (RB867515), before ensiling in minisilos (15 x 30 cm PVC tubes) during 78 days: untreated; urea (5) + sodium benzoate (0.5); urea (7.5) + benzoate (0.5); urea (5) + benzoate (0.75); urea (7.5) + benzoate (0.75); sodium propionate (1, 2 and 4); calcium hydroxide (10). Urea + benzoate in the lowest doses, propionate in the higher concentration and calcium hydroxide were selected, considering the ethanol content (26.5, 27.2 and 7.4 g/kg DM, respectively), total DM loss (88, 46 and 58 g/kg DM, respectively) and digestibility (541, 496 and 516 g/kg DM, respectively) of the silages. Silages treated with these doses of additives and the untreated silage (80 d of storage) were fed (nine + seven d) to 16 castrated male sheep (Santa Inês) housed in metabolic cages. The silage with calcium hydroxide presented coefficients of apparent digestibility of DM (0.44), of NDF (0.4) and DM intake (20 g/kg live weight) in the higher levels. Calcium hydroxide was superior to propionate and urea + benzoate, considering alcoholic fermentation control and reduction of losses in the silage and the forages nutritional value.

O objetivo deste estudo foi indicar um aditivo para a ensilagem da cana-de-açúcar (Saccharum officinarum L.). Em um ensaio de laboratório, nove tratamentos foram aplicados (g de aditivo/kgde forragem fresca - FF) à cana-de-açúcar (RB867515) antes da ensilagem em minisilos (tubos de PVC de 15 x 30 cm) durante 78 d: sem tratamento; uréia (5) + benzoato de sódio (0,5); uréia (7,5) + benzoato (0,5); uréia (5) + benzoato (0,75); uréia (7,5) + benzoato (0,75); propionato de sódio (1, 2 e 4); hidróxido de cálcio (10). Uréia + benzoato nas doses mais baixas, propionato na dose mais alta e hidróxido de cálcio foram selecionados, considerando a concentração de etanol (26,5; 27,2 e 7,4 g/kgMS, respectivamente), perda total de MS (88, 46 e 58 g/kg MS, respectivamente) e digestibilidade (541, 496 e 516 g/kg MS, respectivamente) das silagens. Silagens tratadas com estas dosagens dos aditivos e silagem não tratada (80 d estocagem) foram fornecidas (nove + sete d) a 16 carneiros (Santa Inês) machos castrados mantidos em gaiolas metabólicas. A silagem com hidróxido de cálcio apresentou coeficientes de digestibilidade aparente da MS (0,44), da FDN (0,40) e de ingestão da MS (20 g/kg peso vivo) nos níveis mais altos. Hidróxido de cálcio foi superior ao propionato e à uréia + benzoato, considerando-se o controle da fermentação alcoólica, a redução de perdas e o valor nutritivo da silagem.

Chemical composition, fermentation profile and apparent digestibility of sugarcane silage treated with chemical additives / Composição química, perfil fermentativo e digestabilidade aparente de silagens de cana-de-açúcar tratadas com aditivos químicos

The aim of this study was the indication of an additive for the ensilage of sugarcane (Saccharum officinarum L.). In a laboratory trial, nine treatments were applied (g of additive/kg of fresh forage - FF) to the sugarcane (RB867515), before ensiling in minisilos (15 x 30 cm PVC tubes) during 78 days: untreated; urea (5) + sodium benzoate (0.5); urea (7.5) + benzoate (0.5); urea (5) + benzoate (0.75); urea (7.5) + benzoate (0.75); sodium propionate (1, 2 and 4); calcium hydroxide (10). Urea + benzoate in the lowest doses, propionate in the higher concentration and calcium hydroxide were selected, considering the ethanol content (26.5, 27.2 and 7.4 g/kg DM, respectively), total DM loss (88, 46 and 58 g/kg DM, respectively) and digestibility (541, 496 and 516 g/kg DM, respectively) of the silages. Silages treated with these doses of additives and the untreated silage (80 d of storage) were fed (nine + seven d) to 16 castrated male sheep (Santa Inês) housed in metabolic cages. The silage with calcium hydroxide presented coefficients of apparent digestibility of DM (0.44), of NDF (0.4) and DM intake (20 g/kg live weight) in the higher levels. Calcium hydroxide was superior to propionate and urea + benzoate, considering alcoholic fermentation control and reduction of losses in the silage and the forages nutritional value.(AU)

O objetivo deste estudo foi indicar um aditivo para a ensilagem da cana-de-açúcar (Saccharum officinarum L.). Em um ensaio de laboratório, nove tratamentos foram aplicados (g de aditivo/kgde forragem fresca - FF) à cana-de-açúcar (RB867515) antes da ensilagem em minisilos (tubos de PVC de 15 x 30 cm) durante 78 d: sem tratamento; uréia (5) + benzoato de sódio (0,5); uréia (7,5) + benzoato (0,5); uréia (5) + benzoato (0,75); uréia (7,5) + benzoato (0,75); propionato de sódio (1, 2 e 4); hidróxido de cálcio (10). Uréia + benzoato nas doses mais baixas, propionato na dose mais alta e hidróxido de cálcio foram selecionados, considerando a concentração de etanol (26,5; 27,2 e 7,4 g/kgMS, respectivamente), perda total de MS (88, 46 e 58 g/kg MS, respectivamente) e digestibilidade (541, 496 e 516 g/kg MS, respectivamente) das silagens. Silagens tratadas com estas dosagens dos aditivos e silagem não tratada (80 d estocagem) foram fornecidas (nove + sete d) a 16 carneiros (Santa Inês) machos castrados mantidos em gaiolas metabólicas. A silagem com hidróxido de cálcio apresentou coeficientes de digestibilidade aparente da MS (0,44), da FDN (0,40) e de ingestão da MS (20 g/kg peso vivo) nos níveis mais altos. Hidróxido de cálcio foi superior ao propionato e à uréia + benzoato, considerando-se o controle da fermentação alcoólica, a redução de perdas e o valor nutritivo da silagem.(AU)

Bovine ovarian stem cells differentiate into germ cells and oocyte-like structures after culture in vitro.

Stem cells have been isolated from ovaries, and their ability to differentiate into oocytes in vitro has been demonstrated for mice and human, but not for bovine species. The aims of this study were to isolate germline stem cells from bovine ovaries and to evaluate the effects of bone morphogenetic proteins (BMPs) 2 and 4, and follicular fluid on the differentiation of these stem cells into oocyte-like structures. The ovarian stem cells were isolated and cultured in α-MEM+ supplemented with BMP2, BMP4 or follicular fluid. On days 0 and 14, cells were evaluated for their morphological appearance, viability, expression of alkaline phosphatase and for markers of germ cell formation (VASA and DAZL) and oocyte development (GDF9, ZPA and SCP3) by qPCR. Levels of mRNA were analysed using ANOVA and Bonferroni test (p < .05). The results showed that at day 0, ovarian stem cells expressed specific markers of pluripotency (OCT4, SOX). In addition, these cells were positive for alkaline phosphatase, which is a marker commonly used to identify primordial germ cells (PGCs). After the period of differentiation, cells had morphological features that resemble PGCs and oocyte-like cells (OLCs). An increase, ranging from five to 14 times, in the expression of VASA was observed in cells cultured in medium supplemented with BMPs and follicular fluid, while the increase in DAZL expression ranged from four to six times. In addition, OLCs had an increase in expression of mRNAs for GDF9, ZPA and SCP3 that ranged from two to eight times. In conclusion, OLCs can be differentiated in vitro from ovarian stem cells and BMPs and follicular fluid are effective in stimulating the expression of mRNAs for germ cell and oocyte markers.

Diagnosis and epidemiology of canine leishmaniasis in southeastern Bahia, Brazil.

Leishmaniasis is a disease caused by protozoa of the genus Leishmania. Two distinct forms are recognized: visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). In the Americas, the causative agent of VL is L. infantum chagasi, whereas L. braziliensis is principally responsible for CL. Domestic dogs constitute the main source of VL in urban environments, and have also been implicated in CL epidemiology. We carried out molecular and serological surveys to detect Leishmania infection in dogs from the municipality of Ituberá in Bahia, Brazil. Furthermore, we identified risk factors associated with illness in dogs from this locality. Blood samples were collected from 399 dogs and tested using an indirect immunofluorescence assay (IFA) and polymerase chain reaction (PCR) to detect Leishmania spp antibodies and L. infantum chagasi and L. braziliensis DNA, respectively. Dogs were clinically evaluated and tissue samples from those exhibiting skin lesions were examined for parasites. In addition, the dog owners completed an epidemiological questionnaire to identify factors associated with infection. Skin lesions consistent with CL were found on 37 (9.3%) of the evaluated animals, but parasitological examination was negative for all samples. The IFA returned positive results for 60 (15%) dogs. PCR identified DNA from L. braziliensis in 86 (21.6%) animals, where as all samples proved negative for L. infantum chagasi. The 134 dogs (33.6%) testing positive using IFA and/ or PCR were considered infected, and of these, only 13 demonstrated skin lesions. Animals from rural areas were 3.39-times more likely to be infected compared to those in urban environments.

Protein and messenger RNA expression of interleukin 1 system members in bovine ovarian follicles and effects of interleukin 1ß on primordial follicle activation and survival in vitro.

This study aimed to investigate the expression of interleukin 1 (IL-1) system members (proteins and messenger RNA of ligands and receptors) and its distribution in ovarian follicles of cyclic cows and to evaluate the effects of IL-1ß on the survival and activation of primordial follicles in vitro. The ovaries were processed for localization of IL-1 system in preantral and antral follicles by immunohistochemical, real-time polymerase chain reaction, and Western blot analysis. For in vitro studies, ovarian fragments were cultured in α-MEM(+) supplemented with IL-1ß (0, 1, 10, 50, or 100 ng/mL), and after 6 d, the cultured tissues were processed for histologic analysis. Immunohistochemical results showed that the IL-1 system proteins IL-1ß, IL-1RA, IL-1RI, and IL-1RII were detected in the cytoplasm of oocytes and granulosa cells from all follicular categories and theca cells of antral follicles. Variable levels of messenger RNA for the IL-1 system members were observed at different stages of development. After 6 d of culture, the presence of IL-1ß (10 or 50 ng/mL) was effective in maintaining the percentage of normal follicles and in promoting primordial follicle activation. In conclusion, IL-1 system members are differentially expressed in ovarian follicles according to their stage of development. Moreover, IL-1ß promotes the development of primordial follicles. These results indicate an important role of the IL-1 system in the regulation of bovine folliculogenesis.

Genetic diversity in three natural populations of Pitcairnia flammea (l.) John (Bromeliaceae) estimated by ISSR markers.

Bromeliads are greatly represented in the Atlantic Forest, although many species are threatened with extinction owing to habitat fragmentation and intense extraction for ornamental purposes. Therefore, it is necessary to conduct studies generating knowledge about genetic diversity and the distribution of this diversity among and within natural populations to establish conservation strategies. These studies can be performed with the use of molecular markers. Molecular markers are advantageous for studies of natural populations, for conservation programs, and to aid in properly classifying plant species. This study aimed to evaluate the genetic diversity among and within natural populations of Pitcairnia flammea, occurring in three fragments of the Atlantic Forest in the southern State of Espírito Santo through the use of inter-simple sequence repeat (ISSR) markers. DNA samples from 55 individuals were amplified with 18 ISSR primers, generating 180 bands, 159 of which were polymorphic. The Shannon genetic diversity index ranged from 0.348 to 0.465, with an average of 0.412. The Bayesian approach for the molecular data indicated the existence of two genetic groups. Analysis of molecular variance indicated the existence of 90.3% diversity within the population and 9.74% among populations. The amount of genetic differentiation of populations was moderate (0.0974), indicating that gene flow rates may be enough to counteract the effects of genetic drift. Greater genetic variability found in population B indicates that this area is an important source of genetic variability.

Contributions from the activity analysis to the products development project: case study based on a project of innovation and comfort in aircraft's cabins.

Comfort is an issue that has gained relevance within the aeronautical industry due to the necessity of manufacturers and airline companies of differentiating themselves in a market that has become more and more competitive each day. This study's aim is to analyze the comfort/discomfort of passengers, based on the analysis of the activities performed in the aircrafts' cabin during real flights, in order to create ergonomics requirements and a methodology of comfort analysis. The study has been performed during domestic commercial flights, and the adopted data collection techniques have been: the application of 219 questionnaires to passengers, 44 registrations of postures and actions through filmings and 12 semistructured interviews. The method has made possible the reconstruction of the user's action course in performing activities in real flight situations, and the calculation of the area occupied by the passenger during his or her actions. The integrated analysis of the results corroborates data from previous studies in which both the space made available to each passenger and the activity performed interfere in their perception of comfort. From this study it has been concluded that the method constitutes itself as an innovative tool within the process of aircrafts' cabins project enabling the calculation of the action space based on the reconstructed course.

Activity analysis: contributions to the innovation of projects for aircrafts cabins.

This article presents results obtained from some ergonomics intervention in the project for the conception of aircraft's cabins. The study's aim is to analyze the contribution of the method adopted in the passengers' activities analysis in reference situations, real-use situations in aircraft's cabins, applied to analyze typical activities performed by people in their own environment. Within this perspective, the study shows two analyses which highlight the use of electronic device. The first analysis has been registered through a shooting filming in a real commercial flight. In the second one, the use is developed within the domestic environment. The same method has been applied in both contexts and it is based on activity analysis. Starting with the filming activity, postures and actions analysis, self-confrontation interviews, action course reconstruction and elaboration of postures envelopes. The results point out that the developed method might be applied to different contexts, evincing different ways of space occupation to meet human personal needs while performing an activity, which can help us with the anticipation of the users' needs, as well as indicate some innovation possibilities.

Development of two multiplex mini-sequencing panels of ancestry informative SNPs for studies in Latin Americans: an application to populations of the State of Minas Gerais (Brazil).

Admixture occurs when individuals from parental populations that have been isolated for hundreds of generations form a new hybrid population. Currently, interest in measuring biogeographic ancestry has spread from anthropology to forensic sciences, direct-to-consumers personal genomics, and civil rights issues of minorities, and it is critical for genetic epidemiology studies of admixed populations. Markers with highly differentiated frequencies among human populations are informative of ancestry and are called ancestry informative markers (AIMs). For tri-hybrid Latin American populations, ancestry information is required for Africans, Europeans and Native Americans. We developed two multiplex panels of AIMs (for 14 SNPs) to be genotyped by two mini-sequencing reactions, suitable for investigators of medium-small laboratories to estimate admixture of Latin American populations. We tested the performance of these AIMs by comparing results obtained with our 14 AIMs with those obtained using 108 AIMs genotyped in the same individuals, for which DNA samples is available for other investigators. We emphasize that this type of comparison should be made when new admixture/population structure panels are developed. At the population level, our 14 AIMs were useful to estimate European admixture, though they overestimated African admixture and underestimated Native American admixture. Combined with more AIMs, our panel could be used to infer individual admixture. We used our panel to infer the pattern of admixture in two urban populations (Montes Claros and Manhuaçu) of the State of Minas Gerais (southeastern Brazil), obtaining a snapshot of their genetic structure in the context of their demographic history.

Characterization of a candidate locus for malaria susceptibility in human populations: a (TA)n microsatellite in the promoter region of the CYBB gene, the gp91 phox subunit of the NADPH oxidase.

We have analysed the linkage disequilibrium pattern between the promoter TA microsatellite and Single Nucleotide Polymorphism (SNP) haplotypes for the CYBB gene. None of the CYBB SNPs serve as good surrogates for the microsatellite alleles, previously associated with mild malaria. Thus, the candidate (TA)(n) microsatellite should be directly tested in genetic epidemiology studies.

An attempt to correlate fat and protein content of biological samples with residual carbon after microwave-assisted digestion.

The residual carbon content of a variety of bovine-derived samples and forage was determined by inductively coupled plasma optical emission spectrometry with radial view configuration (ICP-OES) after microwave-assisted digestion under high pressure in a closed vessel. The original carbon concentration in the samples was determined by elemental analysis. The highest amount of original carbon content (64%) was found in viscera. After digestion, up to 75% of it was destroyed. Viscera presented the highest ether extract and blood exhibited a high crude protein content of up to 99%. The efficiency in destroying the organic matter in biological materials seemed to be related to their fat content and showed no significant difficulty for protein-rich samples. The correlation coefficient between the fat content of the samples and the residual carbon after acid decomposition was 0.9173 indicating a fair fit. However, no correlation was observed between % RC and the protein content.

Potentiometric determination of urea by sequential injection using Jack bean meal crude extract as a source of urease.

A sequential injection system was proposed to accomplish the potentiometric determination of urea. This procedure used an ammonium tubular selective electrode to assess ammonium concentration produced by enzymatic hydrolysis of urea from Jack bean meal (Canavalia ensiformis DC) crude extract. A gaseous diffusion device was coupled to the flow set-up allowing on-line sampling and suitable selectivity for determinations. A detection limit of 6.0x10(-4) mol urea l(-1), a relative standard deviation of 1.9% (n=10) and a sampling rate of 20 samples h(-1) were observed when 172 Sumner units (SU) of urease and 900 mul of sample were used. Results agreeing with a comparative method were obtained by the proposed procedure and the use of the crude extract solution combined with the sequential injection approach improved the performance, producing reproducible results and low costs in comparison with procedures using commercial enzymes.

Sistema polivalente de análises químicas por injeção em fluxo: determinação espectrofotométrica de cálcio, magnésio e fósforo em plantas

A polyvalent flow injection system was proposed for spectrophotometric determination of calcium, magnesium and phosphorus in acid plant digests. O-cresolphtalein complexone (CPC) was the chromogenic reagent for calcium and magnesium determination, and ammonium molybdate/vanadate for phosphorus determination. Ammonium-ammonia was elected as buffer system, and EGTA or 8-hydroxyquinoline as the masking agents for calcium or magnesium. Linearity of the calibration equations was observed up to 40.0 mg Ca L-1, 10.0 mg Mg L-1 and 16.0 mg P L-1. Slight variations in the coefficients of the calibration equations (usually 3 %) were found after 4-h working periods. Precise results (r.s.d. 0.02), in agreement with alternative method (flame atomic absorption spectrometry) were obtained. When the system was applied to large scale analysis, good repeatability was observed, and a sample throughput, of about 107 h-1 for magnesium and 75 h-1 for calcium and phosphorus was achieved, emphasizing the simplicity, robustness and versatility inherent to flow analysis.

Um sistema polivalente de análises químicas por injeção em fluxo foi proposto para a determinação de cálcio, magnésio e fósforo em digeridos ácidos de plantas. O-cresolphtaleina complexona (CPC) foi selecionado como reagente colorimétrico para a determinação de cálcio e magnésio e molibdato de amônio/vanadato de amônio para a determinação de fósforo. O sistema empregou tampão amônio-amônia (pH 10,5) e EGTA ou 8-hidroxiquinolina como agentes mascarantes para cálcio ou magnésio, respectivamente. Equações de calibração lineares foram obtidas, sendo que para facilitar a utilização do sistema proposto, foi utilizada curva analítica mista (até 40,0 mg Ca L-1, 10,0 mg Mg L-1 e 16,0 mg P L-1), não sendo observadas interferências entre os elementos. Os limites de detecção foram: 0,10; 0,05 e 0,004 FONT FACE="Symbol">m /font>g L-1 respectivamente para Ca, Mg e P. Pequenas modificações no coeficiente das equações de calibração (normalmente 3%) foram observadas após períodos de 4 h de trabalho. Os resultados apresentaram-se precisos (d.p.r. 0,02), e em concordância com método alternativo (espectrometria de absorção atômica). Quando o sistema foi aplicado a análises em rotina, boa repetibilidade foi observada, sendo obtidas velocidade de amostragem de 107 amostras h-1 para magnésio e 75 amostras h-1 para cálcio e fósforo, enfatizando a simplicidade, robustez e versatilidade, inerentes aos sistemas de análises por injeção em fluxo.

SISTEMA POLIVALENTE DE ANÁLISES QUÍMICAS POR INJEÇÃO EM FLUXO: DETERMINAÇÃO ESPECTROFOTOMÉTRICA DE CÁLCIO, MAGNÉSIO E FÓSFORO EM PLANTAS

A polyvalent flow injection system was proposed for spectrophotometric determination of calcium, magnesium and phosphorus in acid plant digests. O-cresolphtalein complexone (CPC) was the chromogenic reagent for calcium and magnesium determination, and ammonium molybdate/vanadate for phosphorus determination. Ammonium-ammonia was elected as buffer system, and EGTA or 8-hydroxyquinoline as the masking agents for calcium or magnesium. Linearity of the calibration equations was observed up to 40.0 mg Ca L-1, 10.0 mg Mg L-1 and 16.0 mg P L-1. Slight variations in the coefficients of the calibration equations (usually 3 %) were found after 4-h working periods. Precise results (r.s.d. 0.02), in agreement with alternative method (flame atomic absorption spectrometry) were obtained. When the system was applied to large scale analysis, good repeatability was observed, and a sample throughput, of about 107 h-1 for magnesium and 75 h-1 for calcium and phosphorus was achieved, emphasizing the simplicity, robustness and versatility inherent to flow analysis.

Um sistema polivalente de análises químicas por injeção em fluxo foi proposto para a determinação de cálcio, magnésio e fósforo em digeridos ácidos de plantas. O-cresolphtaleina complexona (CPC) foi selecionado como reagente colorimétrico para a determinação de cálcio e magnésio e molibdato de amônio/vanadato de amônio para a determinação de fósforo. O sistema empregou tampão amônio-amônia (pH 10,5) e EGTA ou 8-hidroxiquinolina como agentes mascarantes para cálcio ou magnésio, respectivamente. Equações de calibração lineares foram obtidas, sendo que para facilitar a utilização do sistema proposto, foi utilizada curva analítica mista (até 40,0 mg Ca L-1, 10,0 mg Mg L-1 e 16,0 mg P L-1), não sendo observadas interferências entre os elementos. Os limites de detecção foram: 0,10; 0,05 e 0,004 FONT FACE="Symbol">m /font>g L-1 respectivamente para Ca, Mg e P. Pequenas modificações no coeficiente das equações de calibração (normalmente 3%) foram observadas após períodos de 4 h de trabalho. Os resultados apresentaram-se precisos (d.p.r. 0,02), e em concordância com método alternativo (espectrometria de absorção atômica). Quando o sistema foi aplicado a análises em rotina, boa repetibilidade foi observada, sendo obtidas velocidade de amostragem de 107 amostras h-1 para magnésio e 75 amostras h-1 para cálcio e fósforo, enfatizando a simplicidade, robustez e versatilidade, inerentes aos sistemas de análises por injeção em fluxo.