Ação de herbicidas sobre o crescimento de estirpes de Rhizobium tropici

O objetivo deste trabalho foi avaliar o crescimento das estirpes de Rhizobium tropici BR 322 e BR 520, utilizadas como inoculantes na cultura do feijoeiro no Brasil, em meio de cultura à base de manitol e extrato de levedura (YM) adicionado de diferentes herbicidas (bentazon, metolachlor, imazamox, fluazifop-p-butil, fomesafen e paraquat). Os herbicidas fluazifop-p-butil e fomesafen foram avaliados puros e em mistura comercial, em concentrações variando entre 0,0 e 49,23 mg L-1. O crescimento das estirpes de Rhizobium foi avaliado em espectrofotômetro ao longo de 100 horas de incubação, por meio da leitura da densidade ótica, a 560 nm, sendo, posteriormente, convertido em unidades formadoras de colônia por mL. Observou-se que o paraquat foi o herbicida com maior inibição do crescimento das estirpes avaliadas, seguido pela mistura comercial de fomesafen e fluazifop-p-butil. Para os demais herbicidas, a redução do crescimento não foi significativa. De modo geral, a estirpe BR 520 mostrou-se mais tolerante aos herbicidas testados, com exceção do paraquat. No ensaio de concentrações crescentes do fomesafen, isolado ou em mistura com fluazifop-p-butil, não foi possível determinar o I50 (concentração do herbicida que reduz em 50% o crescimento do rizóbio); a maior redução, de 31,1%, foi observada para a estirpe BR 322 na máxima concentração testada (49,23 mg L-1) da mistura comercial.

Gröngödslingsguide

Denna guide behandlar möjligheterna att använda gröngödsling för att förbättra markkvaliteten. En gröngödslingsvall är ett bra alternativ för växelbruk av gräsvallar också på gårdar som inte annars odlar gräsvall. Frågor kring hur man grundar, sköter och avslutar en gräsvall åskådliggörs med exempel. Dessutom beskrivs ekonomiska kalkyler som beskriver skillnaderna i gräsvallens avkastning och kostnader jämfört med flerårig odling eller monokultur. Denna guide är en del av materialet som TEHO Plus-projektet producerat för jordbrukare och rådgivare och den kompletterar Gårdens miljöhandbok som projektet utarbetat.

Seletividade e eficácia de herbicidas inibidores da enzima accase na cultura da mamona

O experimento foi conduzido com o objetivo de avaliar a seletividade e eficácia de herbicidas inibidores de ACCase na cultura da mamoneira AL Guarany 2002, no município de Paraguaçu Paulista/SP, durante a safra 2002/2003. O delineamento experimental utilizado foi o de blocos ao acaso, com 11 tratamentos e quatro repetições, constituídos pelos herbicidas e adjuvantes: fluazifop-p-butil (313 g ha-1) + Agral® (0,2% v/v); sethoxydim (322 g ha-1) + Assist®(0,5% v/v); haloxyfop-methyl (120 g ha-1) + Assist® (0,5% v/v); clethodim+fenoxaprop-p-ethyl (75 g ha-1) + Assist® (0,5% v/v); quizalofop-p-ethyl (125 g ha¹) + Assist® (0,5% v/v); clethodim (156 g ha-1) + Assist® (0,5% v/v); propaquizafop (175 g ha-1) + Assist® (0,5% v/v); tepraloxydim (400 g ha-1) + Dash® (0,5% v/v); butroxydim (100 g ha-1) + Dash® (0,5% v/v); isoxaflutole (60 g ha-1); e testemunha capinada. No momento da aplicação a mamoneira encontrava-se com 4 a 6 folhas, e o Cenchrus echinatus, com 1 a 5 perfilhos. A mamoneira cv. AL Guarany 2002 apresentou alta seletividade aos herbicidas inibidores de ACCase, não sendo verificada fitointoxicação aos 14 DAA (dias após aplicação), com exceção do tepraloxydim, onde os sintomas persistiram até os 21 DAA, e do isoxaflutole (inibidor de HPPD), por apresentar injúrias nas folhas mais velhas e redução significativa de produtividade. A infestação de C. echinatus foi eficientemente controlada pelos herbicidas inibidores de ACCase entre 14 e 21 DAA (≥ 95,0%).

NH90 helikopterin moottoreiden syklilaskennan tehostaminen ja elinkaarihallinta

Tutkimustyö liittyy NH90 Helikopterin RTM-322 moottoreiden syklivaihdettavi-en osien huollonsuunnitteluun ja sen kehittämiseen. Tavoitteena oli löytää nykyi-sen käyttösyklilaskennan tilalle säästävämpi ratkaisumalli ja saada määritettyä suihkumoottorin osakokonaisuuksille lisälentoaikaa sekä huollonsuunnitteluun järkevämmät käyttöjaksot. Tähän päästiin selvittämällä käytännön lentotoiminnan avulla uudet laskentakertoimet ja -mallit moottorin eri osien eliniän määrittämi-seksi. Konkreettisena tavoitteena oli saada koneen käyttöhistoriaan perustuen kohdeorganisaatiolle esitys, miten moottoreiden käyttösyklilaskentaa tulisi muut-taa ja tehostaa. Diplomityön aihe muodostuu kolmesta tutkimusongelmakokonaisuudesta; moot-torin käyttöhistorian tutkimisesta, moottorivalmistajan hyväksymien syklilasken-tamenetelmien tutkimisesta ja moottorin syklien säästövaikutustarkastelusta tut-kimuksen määrittämillä uusilla laskentamenetelmillä. Tutkimuksen tuloksena muodostui NH90 huollonsuunnitteluun arvio mahdollisis-ta moottorisyklisäästöistä sekä moottoreiden näkökulmasta priorisoitu lista heli-kopterien moottoreiden laitevaihtohuoltojen järjestyksestä seuraavan viiden vuo-den aikana. Syklien säästötarkastelun pohjalta suoritettiin yhden koneen osalta koko käyttöhistorian ajalta takaisinlaskentatarkastelu. Tutkimuksessa selvitettiin Ilmavoimien meneillään olevien projektien valossa moottorisyklien tarkanlasken-nan toteuttamismahdollisuudet tulevaisuudessa. Tutkimuksessa saatujen tulosten avulla vältyttäisiin tulevaisuudessa RTM-322 moottorin ennenaikaisilta laitevaih-doilta koko NH90 kaluston suhteen ja näin saataisiin aikaan merkittävän suuria säästöjä vuoteen 2020 mennessä.

Weed interference periods in the 'Fécula Branca' cassava

This study aimed to determine the periods of weed interference in the first cycle of 'Fécula Branca' cassava. The experiment was arranged in a randomized block design, with four repetitions. The treatments consisted of eight periods of weed control (25, 50, 75, 100, 125, 150, and 175 days after planting - DAP) and eight periods of coexistence between the weed community and the crop (25, 50, 75, 100, 125, 150, and 175), besides control without weeds and control with weeds until harvest (322 DAP). The predominant weed species with higher relative importance were: Avena sativa, Sorghum halepense, Conyza Canadensis, Euphorbia heterophylla, Raphanus raphanistrum, and Commelina benghalensis. It was concluded that, accepting losses of 1% for root and starch production, the period before interference (PBI) was 66 and 70 DAP; the total period of interference prevention (TPIP) was 88 and 91 DAP and the critical period of interference (CPI) was between 66-88 and 70-91 DAP, respectively. For losses of 5% for root and starch production, the PBI was 87 and 88 DAP, and the TPIP 80 and 81 DAP, respectively; in this case, there was no CPI. Considering the average prices of R$ 218.90 t-1 and R$ 1,191.84 t-1, paid in 2012 for root and starch production, respectively, and control cost of R$ 300.00 ha-1 , the root and starch production for the period prior to economic loss (WEEPPEL) could be estimated to be 20 and 24 DAP, respectively.

Fecundidade, dispersão e predação de sementes de Archontophoenix cunninghamiana H. Wendl. & Drude, uma palmeira invasora da Mata Atlântica

Conhecer a biologia de espécies invasoras pode auxiliar na escolha de estratégias de manejo visando seu controle. Este estudo enfoca a fenologia, produção e dispersão de sementes de Archontophoenix cunninghamiana, uma palmeira nativa da Austrália que está invadindo fragmentos de Mata Atlântica. O estudo foi desenvolvido num fragmento florestal de 10 ha (Mata da Cuaso 23º34' S, 46º43' W). Archontophoenix produziu frutos ao longo do ano, apresentando frutos maduros principalmente de outubro a fevereiro. As árvores atingem a maturidade com 18,5 cm DAP, cada uma produzindo 4.119 ± 1.922 sementes ano-1. Aves dispersam as sementes de Archontophoenix e 15% das sementes sobrevivem a predação pós-dispersão até o tempo requerido para germinação. O padrão espacial de predação pós-dispersão e a ausência de predadores de sementes pré-dispersão sugerem a ausência de predadores de sementes de Archontophoenix especializados, conforme predito pela hipótese de liberação de inimigos naturais. Dados deste e de outros estudos indicam um aumento expressivo na produção de sementes de A. cunninghamiana no fragmento em poucos anos. Archontophoenix pode estar se beneficiando da ausência de Euterpe edulis Mart., uma palmeira nativa que possui biologia similar e que foi extinta localmente devido à ação humana. Recomendações para controlar a invasão incluem a remoção contínua de todos Archontophoenix maiores que 15 cm DAP no fragmento e o estabelecimento de uma zona tampão ao redor do fragmento livre de Archontophoenix para dificultar a chegada de propágulos.

Dietary cellulose has no effect on the regeneration of hemoglobin in growing rats with iron deficiency anemia

The objective of the present study was to determine the effect of cellulose on intestinal iron absorption in rats during recovery from iron deficiency anemia. Twenty-one-day-old male Wistar-EPM rats were fed an iron-free ration for two weeks to induce anemia. At 5 weeks of age, the rats were divided into two groups (both groups receiving 35 mg of elemental iron per kg diet): cellulose group (N = 12), receiving a diet containing 100 g of cellulose/kg and control (N = 12), receiving a diet containing no cellulose. The fresh weight of the feces collected over a 3-day period between the 15th and 18th day of dietary treatment was 10.7 ± 3.5 g in the group receiving cellulose and 1.9 ± 1.2 g in the control group (P<0.001). Total food intake was higher in the cellulose group (343.4 ± 22.0 g) than in the control (322.1 ± 13.1 g, P = 0.009) during the 3 weeks of dietary treatment. No significant difference was observed in weight gain (cellulose group = 132.8 ± 19.2, control = 128.0 ± 16.3 g), hemoglobin increment (cellulose group = 8.0 ± 0.8, control = 8.0 ± 1.0 g/dl), hemoglobin level (cellulose group = 12.3 ± 1.2, control = 12.1 ± 1.3 g/dl) or in hepatic iron levels (cellulose group = 333.6 ± 112.4, control = 398.4 ± 168.0 µg/g dry tissue). We conclude that cellulose does not adversely affect the regeneration of hemoglobin, hepatic iron level or the growth of rats during recovery from iron deficiency anemia.

An improved HPLC method for the quantitation of 6-mercaptopurine and its metabolites in red blood cells

A procedure is described for the rapid determination of the intra-erythrocyte concentration of 6-mercaptopurine (6-MP) and its metabolites, 6-thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine (6-MMP). Erythrocytes (8 x 10(8) cells) in 350 µl Hanks solution containing 7.5 mg dithiothreitol were treated with 50 µl 70% perchloric acid. The precipitate was removed by centrifugation (13,000 g) and the supernatant hydrolyzed at 100°C for 45 min. After cooling, 100 µl was analyzed directly by HPLC using a Radialpack Resolve C18 column eluted with methanol-water (7.5:92.5, v/v) containing 100 mM triethylamine. 6-TG, 6-MP and the hydrolysis product of 6-MMP, 4-amino-5-(methylthio)carbonyl imidazole, were monitored at 342, 322 and 303 nm using a Shimadzu SPD-M10A diode array UV detector. The analytes eluted at 5.3, 6.0 and 10.2 min, respectively. The calibration curves were linear (r² > 0.998), and the analytical recoveries were 73.2% for 6-TG, 119.1% for 6-MP and 97.4% for 6-MMP. The intra- and inter-assay variations were highest for 6-MP (9.6 and 14.3%, respectively). The lowest detectable concentrations were 3, 3 and 25 pmol/8 x 10(8) erythrocytes for 6-TG, 6-MP and 6-MMP, respectively. The quantification limits (coefficients of variation <15%) were 8, 10 and 70 pmol/8 x 10(8) erythrocytes for 6-TG, 6-MP and 6-MMP, respectively. The method was applied to the analysis of 183 samples from 36 children under chemotherapy for acute lymphoblastic leukemia. The concentrations of the metabolites in the red cells of the patients ranged from 0 to 1934 pmol/8 x 10(8) erythrocytes for 6-TGN, and from 0 to 105.8 and 0 to 45.9 nmol/8 x 10(8) erythrocytes for 6-MP and 6-MMP, respectively. The procedure gave results that were in agreement with those obtained with other methods designed to detect cases of non-compliance with treatment, including patient interviews and medical evaluation, among others, demonstrating its applicability to monitoring the treatment of leukemic children.

Cyclosporin A preferentially attenuates skeletal slow-twitch muscle regeneration

Calcineurin, a Ca2+/calmodulin-dependent phosphatase, is associated with muscle regeneration via NFATc1/GATA2-dependent pathways. However, it is not clear whether calcineurin preferentially affects the regeneration of slow- or fast-twitch muscles. We investigated the effect of a calcineurin inhibitor, cyclosporin A (CsA), on the morphology and fiber diameter of regenerating slow- and fast-twitch muscles. Adult Wistar rats (259.5 ± 9 g) maintained under standard conditions were treated with CsA (20 mg/kg body weight, ip) for 5 days, submitted to cryolesion of soleus and tibialis anterior (TA) muscles on the 6th day, and then treated with CsA for an additional 21 days. The muscles were removed, weighed, frozen, and stored in liquid nitrogen. Cryolesion did not alter the body weight gain of the animals after 21 days of regeneration (P = 0.001) and CsA significantly reduced the body weight gain (15.5%; P = 0.01) during the same period. All treated TA and soleus muscles showed decreased weights (17 and 29%, respectively, P < 0.05). CsA treatment decreased the cross-sectional area of both soleus and TA muscles of cryoinjured animals (TA: 2108 ± 930 vs 792 ± 640 µm²; soleus: 2209 ± 322 vs 764 ± 439 m²; P < 0.001). Histological sections of both muscles stained with Toluidine blue revealed similar regenerative responses after cryolesion. In addition, CsA was able to minimize these responses, i.e., centralized nuclei and split fibers, more efficiently so in TA muscle. These results indicate that calcineurin preferentially plays a role in regeneration of slow-twitch muscle.

Leptin is not associated independently with hypertension in Japanese-Brazilian women

We evaluated the relationship of leptin with hypertension adjusted for body mass index (BMI) and/or waist circumference in a population of Japanese-Brazilian women aged > or = 30 years with centrally distributed adiposity. After excluding diabetic subjects, the study subjects - who participated in a population-based study on the prevalence of metabolic syndrome - showed prevalence rates of obesity (BMI > or = 25 kg/m²) and central adiposity (waist > or = 80 cm) of 32.0 and 37.8%, respectively. The hypertensive group (N = 162) was older, had higher BMI (24.9 ± 4.2 vs 23.3 ± 3.4 kg/m², P < 0.001), waist circumference (81.1 ± 10.1 vs 76.3 ± 8.2 cm, P < 0.001) and insulin levels (8.0 ± 6.2 vs 7.1 ± 4.9 µU/mL, P < 0.05) than the normotensive group (N = 322) and showed an unfavorable metabolic profile (higher 2-h plasma glucose, C-reactive protein and non-HDL cholesterol levels). Leptin did not differ between groups (8.2 ± 6.8 vs 7.2 ± 6.6 ng/mL, P = 0.09, for hypertensive vs normotensive, respectively) and its levels correlated significantly with anthropometric variables but not with blood pressure. Logistic regression analysis indicated that age and waist were independently associated with hypertension but not with homeostasis model assessment of insulin resistance or leptin levels. The lack of an independent association of hypertension with metabolic parameters (2-h glucose, C-reactive protein and non-HDL cholesterol) after adjustment for central adiposity suggested that visceral fat deposition may be the common mediator of the disturbances of the metabolic syndrome. Our data indicate that age and waist are major determinants of hypertension in this population of centrally obese (waist > or = 80 cm) Japanese-Brazilian women, but do not support a role for leptin in the elevation of blood pressure.

Protein tyrosine kinase inhibitors modify kainic acid-induced epileptiform activity and mossy fiber sprouting but do not protect against limbic cell death

Intrahippocampal administration of kainic acid (KA) induces synaptic release of neurotrophins, mainly brain-derived neurotrophic factor, which contributes to the acute neuronal excitation produced by the toxin. Two protein tyrosine kinase inhibitors, herbimycin A and K252a, were administered intracerebroventricularly, in a single dose, to attenuate neurotrophin signaling during the acute effects of KA, and their role in epileptogenesis was evaluated in adult, male Wistar rats weighing 250-300 g. The latency for the first Racine stage V seizure was 90 ± 8 min in saline controls (N = 4) which increased to 369 ± 71 and 322 ± 63 min in animals receiving herbimycin A (1.74 nmol, N = 4) and K252a (10 pmol, N = 4), respectively. Behavioral alterations were accompanied by diminished duration of EEG paroxysms in herbimycin A- and K252a-treated animals. Notwithstanding the reduction in seizure severity, cell death (60-90% of cell loss in KA-treated animals) in limbic regions was unchanged by herbimycin A and K252a. However, aberrant mossy fiber sprouting was significantly reduced in the ipsilateral dorsal hippocampus of K252a-treated animals. In this model of temporal lobe epilepsy, both protein kinase inhibitors diminished the acute epileptic activity triggered by KA and the ensuing morphological alterations in the dentate gyrus without diminishing cell loss. Our current data indicating that K252a, but not herbimycin, has an influence over KA-induced mossy fiber sprouting further suggest that protein tyrosine kinase receptors are not the only factors which control this plasticity. Further experiments are necessary to elucidate the exact signaling systems associated with this K252a effect.