Superação da dormência de sementes de carrapicho-beiço-de-boi

Visando a obtenção de um tratamento para acelerar a germinação de sementes de Desmodium tortuosum (Sw.) DC., foram realizados dois experimentos, nos quais, segmentos unisseminados de lomentos (testemunha) foram submetidos a debulha manual; debulha manual seguida por escarificação manual empregando-se lixa n. 220; debulha mecânica (processador doméstico ); escarificação química com H2SO4 (95%) por 1,5 e 8 mim pré-aquecimento à 53°C por 4,10 e 16h em estufa com circulação forçada de ar; embebição, utilizando-se H,0 à 80°C por 1,3,5 e 10 min; H20 à 27°C por 2h e embebição com alternância térmica (H,0 à 80°C/ 5min e H20 à 13 °C / 1min) . Para a avaliação dos tratamentos foram empregados os testes de germinação, de emergência de plântulas em solo (E), de primeira contagem de germinação (PG) e de emergência (PE), índices de velocidade de germinação (I.V.G.) e de emergência (I.V.E.), e o comprimento de plântulas (CP). 0 delineamento estatístico adotado foi o inteiramente casualizado com 4 repetições de 100 (G, PG, I.V.G.) ou 20 sementes (C P) por tratamento no primeiro experimento e 4 repetições de 50 (G, PG, I.V.G.) ou 100 sementes (E, PE, I.V.E.) no segundo experimento. No primeiro experimento, os tratamentos que provocaram significativa redução da dormência (D) e, conseqüente elevação da germinação (G), em comparação à testemunha (D=82%; G=15%) foram, em ordem decrescente de eficácia: debulha e escarificação manuais (D=3%; G= 92%), debu lha mecânica (D=13%; G= 81%), embebição em H20 à 80°C por 1min (D=68%; G= 29%) e por 3 min (D=65%; G=32%). No segundo experimento, (testemunha com D=93% e G=3%) destacaram-se: debulha e escarificação manuais (D=2%; G= 93%), debulha mecânica (D = 2%; G = 87%), embebição em H20 à 80°C por 5min e alternância térmica (ambos com D=85% e G= 11%). 0s testes de vigor PC, I.V. G., I.V. E., CP, e E corroboraram esses resultados. 0s métodos de escarificação manual com lixa 220 e debulha mecânica, empregando-se processa dor, podem ser recomendados para a superação da dormência e promoção da germinação de sementes de D. tortuosum.

Estimativa da área foliar de plantas daninhas de ambiente aquático: Eichhornia crassipes

O objetivo deste trabalho foi obter equações que, através de parâmetros lineares dimensionais do limbo e do pecíolo, permitam estimar a área foliar do limbo e a área externa do pulvino de Eichhornia crassipes. Para isso, estudaram-se correlações entre a área foliar real e os parâmetros dimensionais do limbo foliar, como o comprimento ao longo da nervura principal (C) e a largura máxima (L) perpendicular ao eixo principal, assim como correlações entre a área externa real e o comprimento máximo (CP) e o maior diâmetro transversal (DP) do pulvino. Todas as equações lineares simples, geométricas ou exponenciais permitiram boas estimativas da área foliar e área externa do pecíolo. Do ponto de vista prático, sugere-se optar pela equação linear simples envolvendo os respectivos produtos do comprimento pela largura máxima, considerando o coeficiente linear igual a zero. Desse modo, a estimativa da área foliar do limbo (AF) de E. crassipes pode ser feita pela fórmula AF = 0,720 (C x L); e a área externa do pulvino (AP) pode ser estimada pela fórmula AP = 2,378 (CP x DP), com coeficientes de determinação (R²) de 0,9716 e 0,9268, respectivamente.

Competencia de Sicyos polyacanthus en caña de azúcar

Se realizó este ensayo con el objeto de medir los efectos de la competencia permanente y especifica de S. polyacanthus sobre el cultivar CP 74-2005 en la localidad de Monte Rico (27º21'S-65º36'W, Tucumán-Argentina). El diseño experimental, completamente aleatorizado, se estableció en un cañaveral infestado naturalmente. Las parcelas fueron de 64 m² con cuatro surcos de diez metros de largo. Los efectos de la competencia fueron medidos en tres niveles de infestación: Alta (superior a 5 pl m-2), Media (1-4 pl m-2) y Baja (inferior a 1 pl m-2). Las mediciones se efectuaron sobre los dos surcos centrales de la parcela; para altura se analizó el promedio de diez mediciones por infestación y por repetición; y para producción de caña y de azúcar se trabajó con una muestra de caña por parcela, extraída del mismo sitio. Los efectos de la maleza en distinto grado de infestación sobre la altura del cañaveral fueron altamente significativos respecto del testigo obteniéndose pérdidas del 48,58% en baja infestación. En el número de tallos se encontraron pérdidas significativas en los diferentes niveles llegando a 61,87% en infestación alta. En la producción de caña por hectárea se produjeron perdidas de 43,89% en infestación media, mientras que en la producción de azúcar se registraron perdidas de 42,28 y 20,38% en infestación alta y baja respectivamente.

Época de aplicación y toxicidad varietal del herbicida amicarbazone en la caña de azúcar, en Veracruz, México

Durante el ciclo primavera-verano 2005, se establecieron tres experimentos en Úrsulo Galván, Ver., México, con el objetivo de determinar la mejor época de aplicación del herbicida amicarbazone en la caña de azúcar en condiciones de riego e identificar la susceptibilidad de las tres principales variedades cultivadas en el estado a este herbicida. En un experimento, se evaluó el control de malezas con amicarbazone a 0,7, 1,05 y 1,4 kg ha‑1 aplicado en cuatro épocas: preemergencia antes del riego de germinación, preemergencia después del riego de germinación, postemergencia temprana y postemergencia tardía. En los otros experimentos, se evaluó la toxicidad de amicarbazone a 0, 0,7, 1,4 y 2,1 kg ha-1, aplicado en preemergencia y postemergencia en las variedades de caña de azúcar Mex 69-290, CP 72‑2086 y Mex 79-431. El quelite rastrero (Amaranthus lividus) fue mejor controlado con aplicaciones postemergentes de amicarbazone, a partir de 0,7 kg ha-1. Por su parte, el control del zacate Guinea (Megathyrsus maximus) fue bajo en todas las épocas de aplicación. En aplicaciones preemergentes, el amicarbazone hasta 2,1 kg ha-1 fue altamente selectivo a todas las variedades evaluadas, mientras que, cuando fue aplicado en postemergencia, ocasionó ligera toxicidad a las tres variedades de caña de azúcar, la cual fue mayor conforme se incrementó la dosis. Sin embargo, los daños desaparecieron entre los 30 y 45 días después de la aplicación y no ocasionaron reducción permanente en la altura de las plantas.

Hydrolysis of xylans by enzyme systems from solid cultures of Trichoderma harzianum strains

Xylanase activity was isolated from crude extracts of Trichoderma harzianum strains C and 4 grown at 28oC in a solid medium containing wheat bran as the carbon source. Enzyme activity was demonstrable in the permeate after ultrafiltration of the crude extracts using an Amicon system. The hydrolysis patterns of different xylans and paper pulps by xylanase activity ranged from xylose, xylobiose and xylotriose to higher xylooligosaccharides. A purified ß-xylosidase from the Trichoderma harzianum strain released xylose, xylobiose and xylotriose from seaweed, deacetylated, oat spelt and birchwood xylans. The purified enzyme was not active against acetylated xylan and catalyzed the hydrolysis of xylooligosaccharides, including xylotriose, xylotetraose and xylopentaose. However, the enzyme was not able to degrade xylohexaose. Xylanase pretreatment was effective for hardwood kraft pulp bleaching. Hardwood kraft pulp bleached in the XEOP sequence had its kappa number reduced from 13.2 to 8.9 and a viscosity of 20.45 cp. The efficiency of delignification was 33%.

A search for RNA insertions and NS3 gene duplication in the genome of cytopathic isolates of bovine viral diarrhea virus

Calves born persistently infected with non-cytopathic bovine viral diarrhea virus (ncpBVDV) frequently develop a fatal gastroenteric illness called mucosal disease. Both the original virus (ncpBVDV) and an antigenically identical but cytopathic virus (cpBVDV) can be isolated from animals affected by mucosal disease. Cytopathic BVDVs originate from their ncp counterparts by diverse genetic mechanisms, all leading to the expression of the non-structural polypeptide NS3 as a discrete protein. In contrast, ncpBVDVs express only the large precursor polypeptide, NS2-3, which contains the NS3 sequence within its carboxy-terminal half. We report here the investigation of the mechanism leading to NS3 expression in 41 cpBVDV isolates. An RT-PCR strategy was employed to detect RNA insertions within the NS2-3 gene and/or duplication of the NS3 gene, two common mechanisms of NS3 expression. RT-PCR amplification revealed insertions in the NS2-3 gene of three cp isolates, with the inserts being similar in size to that present in the cpBVDV NADL strain. Sequencing of one such insert revealed a 296-nucleotide sequence with a central core of 270 nucleotides coding for an amino acid sequence highly homologous (98%) to the NADL insert, a sequence corresponding to part of the cellular J-Domain gene. One cpBVDV isolate contained a duplication of the NS3 gene downstream from the original locus. In contrast, no detectable NS2-3 insertions or NS3 gene duplications were observed in the genome of 37 cp isolates. These results demonstrate that processing of NS2-3 without bulk mRNA insertions or NS3 gene duplications seems to be a frequent mechanism leading to NS3 expression and BVDV cytopathology.

Effect of 5-HT1B receptor agonists injected into the prefrontal cortex on maternal aggression in rats

Serotonin (5-HT1B) receptors play an essential role in the inhibition of aggressive behavior in rodents. CP-94,253, a 5-HT1B receptor agonist, can reduce aggression in male mice when administered directly into the ventro-orbitofrontal (VO) prefrontal cortex (PFC). The objective of the current study was to assess the effects of two selective 5-HT1B receptor agonists (CP-94,253 and CP-93,129), microinjected into the VO PFC, on maternal aggressive behavior after social instigation in rats. CP-94,253 (0.56 µg/0.2 µL, N = 8, and 1.0 µg/0.2 µL, N = 8) or CP-93,129 (1.0 µg/0.2 µL, N = 9) was microinjected into the VO PFC of Wistar rats on the 9th day postpartum and 15 min thereafter the aggressive behavior by the resident female against a male intruder was recorded for 10 min. The frequency and duration of aggressive and non-aggressive behaviors were analyzed using ANOVA and post hoc tests. CP-93,129 significantly decreased maternal aggression. The frequency of lateral attacks, bites and pinnings was reduced compared to control, while the non-aggressive behaviors and maternal care were largely unaffected by this treatment. CP-94,253 had no significant effects on aggressive or non-aggressive behaviors when microinjected into the same area of female rats. CP-93,129, a specific 5-HT1B receptor agonist, administered into the VO PFC reduced maternal aggressive behavior, while the CP-94,253 agonist did not significantly affect this behavior after social instigation in female rats. We conclude that only the 5-HT1B receptor agonist CP-93,129 administered into the VO PFC decreased aggression in female rats postpartum after social instigation.

N-terminal prohormone brain natriuretic peptide (NT-proBNP) as a noninvasive marker for restrictive syndromes

Constrictive pericarditis (CP) and restrictive cardiomyopathy share many similarities in both their clinical and hemodynamic characteristics and N-terminal prohormone brain natriuretic peptide (NT-proBNP) is a sensitive marker of cardiac diastolic dysfunction. The objectives of the present study were to determine whether serum NT-proBNP was high in patients with endomyocardial fibrosis (EMF) and CP, and to investigate how this relates to diastolic dysfunction. Thirty-three patients were divided into two groups: CP (16 patients) and EMF (17 patients). The control group consisted of 30 healthy individuals. Patients were evaluated by bidimensional echocardiography, with restriction syndrome evaluated by pulsed Doppler of the mitral flow and serum NT-proBNP measured by immunoassay and detected by electrochemiluminescence. Spearman correlation coefficient was used to analyze the association between log NT-proBNP and echocardiographic parameters. Log NT-proBNP was significantly higher (P < 0.05) in CP patients (log mean: 2.67 pg/mL; 95%CI: 2.43-2.92 log pg/mL) and in EMF patients (log mean: 2.91 pg/mL; 95%CI: 2.70-3.12 log pg/mL) compared with the control group (log mean: 1.45; 95%CI: 1.32-1.60 log pg/mL). There were no statistical differences between EMF and CP patients (P = 0.689) in terms of NT-proBNP. The NT-proBNP log tended to correlate with peak velocity of the E wave (r = 0.439; P = 0.060, but not with A wave (r = -0.399; P = 0.112). Serum NT-proBNP concentration can be used as a marker to detect the presence of diastolic dysfunction in patients with restrictive syndrome; however, serum NT-proBNP levels cannot be used to differentiate restrictive cardiomyopathy from CP.

High-frequency electroacupuncture versus carprofen in an incisional pain model in rats

The objective of the present study was to compare the effect of electroacupuncture (EA) and carprofen (CP) on postoperative incisional pain using the plantar incision (PI) model in rats. A 1-cm longitudinal incision was made through skin, fascia and muscles of a hind paw of male Wistar rats and the development of mechanical and thermal hypersensitivity was determined over 4 days using the von Frey and Hargreaves methods, respectively. Based on the experimental treatments received on the third postoperative day, the animals were divided into the following groups: PI+CP (CP, 2 mg/kg, po); PI+EAST36 (100-Hz EA applied bilaterally at the Zusanli point (ST36)); PI+EANP (EA applied to a non-acupoint region); PI+IMMO (immobilization only); PI (vehicle). In the von Frey test, the PI+EAST36 group had higher withdrawal force thresholds in response to mechanical stimuli than the PI, PI+IMMO and PI+EANP groups at several times studied. Furthermore, the PI+EAST36 group showed paw withdrawal thresholds in response to mechanical stimuli that were similar to those of the PI+CP group. In the Hargreaves test, all groups had latencies higher than those observed with PI. The PI+EAST36 group was similar to the PI+IMMO, PI+EANP and PI+CP groups. We conclude that 100-Hz EA at the ST36 point, but not at non-acupoints, can reduce mechanical nociception in the rat model of incisional pain, and its effectiveness is comparable to that of carprofen.

Effects of melatonin on DNA damage induced by cyclophosphamide in rats

The antioxidant and free radical scavenger properties of melatonin have been well described in the literature. In this study, our objective was to determine the protective effect of the pineal gland hormone against the DNA damage induced by cyclophosphamide (CP), an anti-tumor agent that is widely applied in clinical practice. DNA damage was induced in rats by a single intraperitoneal injection of CP (20 or 50 mg/kg). Animals received melatonin during the dark period for 15 days (1 mg/kg in the drinking water). Rat bone marrow cells were used for the determination of chromosomal aberrations and of formamidopyrimidine DNA glycosylase enzyme (Fpg)-sensitive sites by the comet technique and ofXpf mRNA expression by qRT-PCR. The number (mean ± SE) of chromosomal aberrations in pinealectomized (PINX) animals treated with melatonin and CP (2.50 ± 0.50/100 cells) was lower than that obtained for PINX animals injected with CP (12 ± 1.8/100 cells), thus showing a reduction of 85.8% in the number of chromosomal aberrations. This melatonin-mediated protection was also observed when oxidative lesions were analyzed by the Fpg-sensitive assay, both 24 and 48 h after CP administration. The expression of Xpf mRNA, which is involved in the DNA nucleotide excision repair machinery, was up-regulated by melatonin. The results indicate that melatonin is able to protect bone marrow cells by completely blocking CP-induced chromosome aberrations. Therefore, melatonin administration could be an alternative and effective treatment during chemotherapy.

Caracterização de propriedades mecânicas e óticas de biofilmes a base de proteínas miofibrilares de tilápia do nilo usando uma metodologia de superfície-resposta

Biopolímeros como polissacarídeos e proteínas, têm despertado interesse recentemente, como matérias primas para embalagens comestíveis e/ou biodegradáveis. Os materiais a serem desenvolvidos devem possuir boas propriedades mecânicas e aparência, para proteger e apresentar o produto embalado. Este trabalho teve como objetivo a caracterização das propriedades mecânicas e óticas de biofilmes à base de proteínas miofibrilares de tilápia-do-nilo, em função do pH (2,0-3,0), da concentração de proteína (Cp= 0,5-2,0g/100g solução) e do teor de glicerol (Cg= 30-70g/100g proteína) da solução filmogênica (SF). Foram determinadas a força e a deformação na ruptura por teste de perfuração e a opacidade aparente através de espectrofotometria, à 22ºC e umidade relativa ambiente. Os biofilmes obtidos nessas condições de ensaio apresentaram-se manuseáveis e transparentes. A força e a deformação na ruptura apresentaram comportamentos opostos em função da Cg (pH= 2,5 e Cp= 1,25 g/100g solução): a variação da Cg de 30 a 70% provocou uma variação na força e na deformação na ruptura entre 6,67N e 2,94N e 2,71% e 7,5%, respectivamente. A Cg e o pH exercem influência significativa sobre a força na ruptura (p< 0,05). Porém nenhum dos fatores estudados demonstrou ter influência significativa sobre a deformação na ruptura ou sobre a opacidade aparente dos biofilmes.

Comportamento do óleo de soja refinado utilizado em fritura por imersão com alimentos de origem vegetal

A fritura é uma operação que confere aos alimentos características de odor, sabor, cor e textura de grande aceitabilidade sensorial. O óleo ou gordura pode, entretanto, se tornar um ingrediente capaz de introduzir alterações químicas provocadas pelo aquecimento prolongado. Neste trabalho, estudou-se o comportamento do óleo de soja refinado em fritura de imersão intermitente, em restaurante universitário, sob temperatura controlada entre 170ºC e 180ºC, por um período de 30 horas. Foram utilizados 101 litros de óleo de soja para processar 373kg de vegetais, como batata, couve-flor, abobrinha e mandioca. Analisou-se o óleo mediante determinações físicas de absortividade no u.v. (A232nm e A270nm) e cor (Lovibond), e químicas (índice de acidez (IA) e compostos polares (CP)). Análise sensorial de aceitabilidade foi realizada nos produtos. Os parâmetros-limite que determinaram o descarte do óleo foram: 25% de compostos polares, 1% de ácidos graxos livres e média de 7,0 para o teste de aceitabilidade. Os resultados ao final do período foram: IA, 0,282; CP, 18,8%; cor Lovibond 14Y/2R; A232nm de 9,213; A270nm de 2,409 e 7,96 para o teste de aceitabilidade. Com base nos resultados obtidos, concluiu-se que, apesar do aquecimento do óleo ter levado a alterações hidrolíticas e oxidativas, os parâmetros não atingiram o nível de descarte, indicando que o óleo de soja submetido a essas condições de fritura pode ser usado por 30 horas.

Nutrients in the cassava (Manihot esculenta Crantz) leaf meal at three ages of the plant

The high number of cassava cultivars adapted to many different regions provides a wide variation in the chemical composition of cassava leaves meal (CLM). Therefore, the contents of some nutrients in CLM from five cultivars at three ages of the plant were investigated in order to select the cultivars and ages with superior levels of these nutrients. When the plants were 12 months old, the highest levels of crude protein (CP), beta-carotene, iron, magnesium, phosphorus and sulfur were observed. The IAC 289-70 cv. showed the highest levels of magnesium, as well as considerable contents of CP, beta-carotene, iron, zinc and sulfur, which did not differ statistically from the cultivars showing the highest levels of these nutrients.

Avaliação da sensibilidade de cepas de Escherichia coli isoladas de mexilhões (Perna perna linnaeus, 1758) à antimicrobianos

Foram avaliadas 44 cepas de Escherichia coli isoladas de amostras cárneas de mexilhões capturados no município de Niterói, Estado do Rio de Janeiro, quanto a sua sensibilidade a antimicrobianos. Vinte e quatro antimicrobianos foram testados e padrões variáveis de comportamento frente aos mesmos foram observados. Todas as cepas avaliadas apresentaram sensibilidade total a apenas 41,66% dos antimicrobianos (R, Ac, C, To, Fx, Cz, Ct, Nt, Cp, Ge) e resistência total a 4,16% dos antimicrobianos (Ca). A cepa número 18 apresentou sensibilidade a 95,83% dos antimicrobianos, enquanto que a cepa número 30 aduziu resistência a 41,66% dos antimicrobianos. Frente aos resultados obtidos é importante ponderarmos sobre o risco à Saúde Pública associado ao hábito de ingerir pescado cru ou insuficientemente cozido, especialmente bivalves filtradores contaminados por bactérias com comprovada resistência a diferentes antimicrobianos, alimentos potencialmente envolvidos em processos de reinfecção do homem, no qual desencadeiam quadros de gastroenterite.

Effect of genotype, finishing system, and sex on physiochemical characteristics of goat meat

Seventy-eight kids of both sexes and five genotypes were used: Alpine, ½ Boer + ½ Alpine (½ BA), ¾ Boer + ¼ Alpine, ½ Anglo-nubian + ½ Alpine and "tricross" (½ Anglo-nubian + ¼ Boer + ¼ Alpine) with initial average weight of 14.1 ± 2.5. The objective was to evaluate the effect of genotype, finishing system, and sex on the physiochemical characteristics of goat meat. Finishing systems were: ST1 - kid + dam in pasture and ST2 - weaned kid and feedlot. Kids in ST1 were kept in an area with Panicum maximum cv. Tanzania, and after grazing, water and mineral salt/mix were fed ad libitum to the animals. The animals in ST2 were confined in collective pens distributed according to genotypes and received diet with 16% CP and 73% TDN. The values of pH, a* (red content), Cooking Loss (CL), and Ether Extract (EE) percentage were influenced by genotype. Values for red content (a*) and L* (brightness), CL and percentages of moisture, protein, EE, and ash were influenced by the finishing system. Longissimus dorsi muscle from animals ½ BA exhibited better physiochemical characteristics. For greater tenderness and higher percentages of fat, consumers should choose female kid goat meat.