O tratamento de pré-emergência com o 2, 4-D no milho

In order to study the action of herbicides - sodium salt, amine salt and ester of 2,4-D, TCA and 2,4,5-T a preliminary experiment for pre-emergence weed control was corried out, and the corresponding results are given in table I and II. The corn used in the experiments was of the flint type 1A 3531. The loam soil on which the experiment has been carried out is called "terra roxa". All treatments were highly significant when compared with the check plots, except the 2B one in the control of broad leaf weeds, and 4B in the control of grass weeds. Among these treatments there are no significant differences. But we note the following: (table I). a) treatments of higher concentrations were superior to lower ones. b) the treatments which gave the best control for broad leaf weeds were in the following decreasing order: 1A, 5A and 3A. For grass weeds, they were 5A, 1A and 3A. c) the amine 2,4-D (600 grs. per hectare) supplied very good control when we get into consideration that on the acid basis, it was in very low concentration. d) TCA in high concentration affected the germination, growth and yield, in the lower one it did not show good control of weeds, especially of grasses. It is not suitable for pre-emergence control in corn. e) 2,4,5-T was not better than the 2,4-D products. As it is much more expensive than the others, economically its use in pre-emergence weed control in corn is not praticable. f) all the products used controled grass weeds as well as broad leaf ones; this show the superiority of the pre-emergence treatment method over that of post-emergence. g) Even a dose as strong as the treatment 1A (3.400g. of 2,4-D acid per hectare) did not damage corn production (table II). h) the superiority noted in the production of all the treatments with the exception of 2A, which damaged the plants, we atribute to the lack of competion between corn and weeds; all chek-plots suffered this competition, because they were not Probably, there was, also, hormonial effect of 2,4-D on the corn plant. Not withstanding the fact that the present experiment has been successful, we think that new researches are necessary, especially with the purpose of studying factors as climate and soil which in other countries, interferred with the success of the pre-emergence weed control.

In Vitro and in Vivo Assays of 3,5-Disubstituted-Tetrahydro-2H-1,3,5-Thiadiazin-2-Thione Derivatives against Trypanosoma cruzi

Cytotoxicity assays of 24 new 3,5-disubstituted-tetrahydro-2H-1,3,5-thiadiazin-2-thione derivatives were performed. The 17 compounds with higher anti-epimastigote activity and lower cytotoxicity were, thereafter, screened against amastigote of Trypanosoma cruzi. Out of these 17 derivatives S-2d was selected to be assayed in vivo, because of its remarkable trypanocidal properties. To determine toxicity against J774 macrophages, a method based on quantification of cell damage, after 24 h, was used. Cell respiration, an indicator of cell viability, was assessed by the reduction of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] to formazan. Anti-amastigote activity was estimated after 48 h by microscopic counts of May Grünwald-Giemsa-stained monolayers. Nifurtimox and benznidazole were used as reference drugs. For the in vivo experiences, mice were infected with 10(4) blood trypomastigotes and then treated during 15 days with S-2d or nifurtimox by oral route. All of the compounds were highly toxic at 100 µg/ml for macrophages and a few of them maintained this cytotoxicity even at 10 µg/ml. Of the derivatives assayed against amastigotes 3k and S-2d showed an interesting activity, that was held even at 1µg/ml. It is demonstrated that the high anti-epimastigote activity previously reported is mainly due to the non-specific toxicity of these compounds. In vivo assays assessed a reduction of parasitemia after administration of S-2d to infected mice.

Anti-leishmanial and structure-activity relationship of ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl)-2-propen-1-one derivatives

A series of ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl)-2-propen-1-one derivatives were synthesized and tested for in vitro leishmanicidal activity against amastigotes of Leishmania amazonensis in axenical cultures and murine infected macrophages. Structure-activity relationships demonstrated the importance of a radical methoxy at position R3', R4' and R5'. (2E)-3-(3,4,5-trimethoxy-phenyl)-1-(3,6,7-trimethyl-1,4-dioxy-quinoxalin-2-yl)-propenone was the most active. Cytotoxicity on macrophages revealed that this product was almost six times more active than toxic.

Danos ao DNA promovidos por ácido 5-aminolevulínico: possível associação com o desenvolvimento de carcinoma hepatocelular em portadores de porfiria aguda intermitente

5-Aminolevulinic acid (ALA) is a heme precursor accumulated in acute intermittent porphyria (AIP), which might be associated with hepatocellular carcinoma (HCC) in symptomatic patients. Under metal catalyzed oxidation, ALA and its cyclic dimerization product, 3,6-dihydropyrazine-2,5-dipropanoic acid, produce reactive oxygen species that damage plasmid and calf thymus DNA bases, increase the steady state level of 8-oxo-7,8-dihydro-2´-deoxyguanosine in liver DNA and promote mitochondrial DNA damage. The final product of ALA, 4,5-dioxovaleric acid (DOVA), is able to alkylate guanine moieties, producing adducts. ALA and DOVA are mutagenic in bacteria. This review shows an up-to-date literature data that reinforce the hypothesis that the DNA damage induced by ALA may be associated with the development of HCC in AIP patients.

Measuring air pressure with a polymeric gas sensor

In this communication we describe the application of a conductive polymer gas sensor as an air pressure sensor. The device consists of a thin doped poly(4'-hexyloxy-2,5-biphenylene ethylene) (PHBPE) film deposited on an interdigitated metallic electrode. The sensor is cheap, easy to fabricate, lasts for several months, and is suitable for measuring air pressures in the range between 100 and 700 mmHg.

Fatores perinatais associados a recém-nascidos de termo com pH<7,1 na artéria umbilical e índice de Apgar <7,0 no 5º minuto

OBJETIVO: Avaliar os fatores perinatais associados a recém-nascidos de termo com pH<7,1 na artéria umbilical e índice de Apgar no 5º min<7,0. MÉTODOS: Estudo retrospectivo com delineamento caso-controle, realizado após revisão dos prontuários de todos os nascimentos ocorridos entre setembro/1998 e março/2008, no Hospital Geral de Caxias do Sul. Foi considerado fator de inclusão os recém-nascidos de termo que apresentaram índice de Apgar no 5º min <7,0 e pH de artéria umbilical <7,1. Na análise univariada foi utilizado o teste t de Student e Mann-Whitney para as variáveis contínuas, o teste do c² para as variáveis dicotômicas e estimativa de risco pelo odds ratio (OR). Foi utilizado um valor de p<0,05 como estatisticamente significativo. RESULTADOS: De um total de 15.495 nascimentos consecutivos observaram-se 25 neonatos (0,16%) de termo com pH<7,1 na artéria umbilical e índice de Apgar no 5º min <7,0. Apresentaram associação significativa com o evento acidótico a apresentação pélvica (OR=12,9; p<0,005), parto cesáreo (OR=3,5; p<0,01) e cardiotocografia intraparto alterada (OR=7,8; p<0,02). Dentre as características fetais, associaram-se o déficit de base (-15,0 versus -4,5; p<0,0001), necessidade de internação em unidade de terapia intensiva neonatal (OR=79,7; p<0,0001) e necessidade de reanimação (OR=12,2; p<0,0001). CONCLUSÃO: Baixo índice de Apgar no 5º min de vida associado a pH<7,1 na artéria umbilical pode predizer desfechos neonatais desfavoráveis.

Atividade de três drogas antivirais sobre os herpesvírus bovino tipos 1, 2 e 5 em cultivo celular

A atividade de três fármacos antivirais (Aciclovir [ACV], Ganciclovir [GCV] e Foscarnet [PFA]) foi testada in vitro frente aos herpesvírus bovino tipos 1 (BoHV-1), 2 (BoHV-2) e 5 (BoHV-5). Para isso, utilizou-se o teste de reducao de placas virais em cultivo celular, testando-se diferentes concentracoes dos farmacos frente a 100 doses infectantes para 50% dos cultivos celulares (DICC50) dos respectivos virus. Pelo teste de MTT (3-(4,5-Dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide), verificou-se que concentracoes inferiores a 200ƒÊg/mL dos tres antivirais resultaram em indices de viabilidade de celulas MDBK e Hep2 superiores a 80%. Com base na concentracao citotoxica para 50% das celulas (CC50) e na concentracao dos farmacos efetiva para inibir em 50% o numero de placas virais (EC50), calculou-se o indice de seletividade (IS) dos antivirais para os tres herpesvirus. Assim, o ACV demonstrou ser moderadamente ativo frente ao BoHV-1 (EC50: 112,9ƒÊg/mL e IS: 4,5), ao BoHV-2 (EC50: 114,2 ƒÊg/mL e IS: 4,5) e BoHV-5 (EC50: 96,9ƒÊg/mL e IS: 5,3). O GCV apresentou atividade moderada frente ao BoHV-2 (EC50: 33,5ƒÊg/mL e IS: 16,6) e, em menor grau, contra o BoHV-5 (EC50: 123,2ƒÊg/mL e IS: 4,5), sendo ineficaz frente ao BoHV-1 (EC50: 335,8ƒÊg/mL e IS: 1,7). O PFA apresentou atividade antiviral mais pronunciada, sendo o unico farmaco que, na concentracao de 100ƒÊg/mL, inibiu completamente a producao de placas pelos tres virus testados. O PFA foi o mais efetivo in vitro frente ao BoHV-1 (EC50: 29,5ƒÊg/mL e IS: 42,2), ao BoHV-2 (EC50: 45,2ƒÊg/mL e IS: 27,6) e ao BoHV-5 (EC50: 7,8ƒÊg/mL e IS: 160,6). Portanto, os resultados obtidos indicam que o PFA pode se constituir em um candidato para terapia experimental de infeccoes pelos herpesvirus de bovinos in vivo.

A thymidine kinase-negative bovine herpesvirus 5 is highly attenuated for rabbits, but is neuroinvasive and establishes latent infection

Mutant viral strains deleted in non-essential genes represent useful tools to study the function of specific gene products in the biology of the virus. We herein describe an investigation on the phenotype of a bovine herpesvirus 5 (BoHV-5) recombinant deleted in the gene encoding the enzyme thymidine kinase (TK) in rabbits, with special emphasis to neuroinvasiveness and the ability to establish and reactivate latent infection. Rabbits inoculated with the parental virus (SV-507/99) (n=18) at a low titer (10(5.5)TCID50) shed virus in nasal secretions in titers up to 10(4.5)TCID50 for up to 12 days (average: 9.8 days [5-12]) and 5/ 16 developed neurological disease and were euthanized in extremis. Rabbits inoculated with the recombinant BoHV-5TKΔ at a high dose (10(7.1)TCID50) also shed virus in nasal secretions, yet to lower titers (maximum: 10(2.3)TCID50) and for a shorter period (average: 6.6 days [2-11]) and remained healthy. PCR examination of brain sections of inoculated rabbits at day 6 post-infection (pi) revealed a widespread distribution of the parental virus, whereas DNA of the recombinant BoHV-5TKΔ-was detected only in the trigeminal ganglia [TG] and olfactory bulbs [OB]. Nevertheless, during latent infection (52pi), DNA of the recombinant virus was detected in the TGs, OBs and also in other areas of the brain, demonstrating the ability of the virus to invade the brain. Dexamethasone (Dx) administration at day 65 pi was followed by virus reactivation and shedding by 5/8 rabbits inoculated with the parental strain (mean duration of 4.2 days [1 - 9]) and by none of seven rabbits inoculated with the recombinant virus. Again, PCR examination at day 30 post-Dx treatment revealed the presence of latent DNA in the TGs, OBs and in other areas of the brain of both groups. Taken together, these results confirm that the recombinant BoHV-5TKΔ is highly attenuated for rabbits. It shows a reduced ability to replicate in the nose but retains the ability to invade the brain and to establish latent infection. Additional studies are underway to determine the biological and molecular mechanisms underlying the inability of BoHV-5TKΔ to reactivate from latency.

Concomitant infection of Neospora caninum and Bovine Herpesvirus type 5 in spontaneous bovine abortions

Bovine Herpesvirus type 5 (BoHV-5) has not been conclusively demonstrated to cause bovine abortion. Brain lesions produced by Neospora caninum and Bovine Herpesvirus type 1 (BoHV-1) exhibit common features. Therefore, careful microscopic evaluation and additional diagnostic procedures are required to achieve an accurate final etiological diagnosis. The aim of the present work was to investigate the occurrence of infections due to BoHV-1, BoHV-5 and N. caninum in 68 cases of spontaneous bovine abortions which showed microscopic lesions in the fetal central nervous system. This study allowed the identification of 4 (5.9%) fetuses with dual infection by BoHV-5 and N. caninum and 33 (48.5%) cases in which N. caninum was the sole pathogen identified. All cases were negative to BoHV-1. The results of this study provide evidence that dual infection by BoHV-5 and N. caninum occur during pregnancy in cattle; however, the role of BoHV-5 as a primary cause of bovine abortion needs further research. Molecular diagnosis of BoHV-5 and N. caninum confirmed the importance of applying complementary assays to improve the sensitivity of diagnosing bovine abortion.

Avaliação de herbicidas no controle de plantas daninhas na cultura da soja

Foi conduzido em Serranópolis, GO, um ensaio objetivando avaliar a eficiência e a seletividade de herbicidas no controle de plantas daninhas na cultura da soja (Glycine max (L.) Merril), utilizando-se os seguintes tratamentos: A) 100 g/ha de imazethapyr (ácido 2-[4,5-dihidro-4-metil-4(1-metiletil)-5-oxo-1H-imidazol-2-ilo]-5-etil-3-piridinacarboxilico) + surfactante, a 0,25% v/v; B) tratamento A e 15 dias após, 230 g/ha de sethoxydim (2-1-etoximino-butil-5-2(etiltio)-propil-3-hidroxi-2-ciclohexeno-1-ona) + óleo mineral, a 0,25% v/v; C) 230 g/ha de sethoxydim + óleo mineral, a 0,25% v/v; D) 480 + 200 + 230 g/ha de bentazon (3-isopropil-2,1,3-benzotiadiazinona-(4)-2,2-dióxido) + fomesafen (5-)2-cloro-4-(trifluorometil-fenoxi)N-metilsulfonil-2-nitrobenzamida) + sethoxydim + óleo mineral, 0,25% v/v; E) 150 g/ha de imazaquim (2-[4,5-dihidro-4-metil-4-(1-metiletil)-5-oxo-1H-imidazol-2-ilo]-3-quinolinacarboxílico) pré-e e 230 g/ha de sethoxydim + óleo mineral, 0,25% v/v; F) 250 g/ha de fomesafen + 187 g/ha de fluazipop-p-butil (butil-(R)-2-(4-(5-trifluorometil-2-piridiloxi)-fenoxi)-propionato) + surfactante a 0,2% v/v; G) 120 g/ha de imazethapyr + surfactante a 0,2% v/v; H) testemunha capinada; I) testemunha não capinada. O delineamento experimental foi de blocos ao acaso, com quatro repetições. O capim-custódio (Pennisetum setosum (Swartz) L. Rich) foi eficientemente controlado por todos os tratamentos químicos, enquanto a falsa-serralha (Emilia sonchifolia DC.) foi somente pelo tratamento D. O capim-carrapicho (Cenchrus echinatus L.) por C, D, E e F. O joá-de-capote (Nicandra physaloides (L.) Pers.) por D.F. e G. Ocorreram injúrias iniciais às plantas de soja, nos tratamentos D, E. e F. As alturas de plantas e de inserção da primeira vagem, além do rendimento de grãos, não foram influenciados significativamente pelos herbicidas.

Influência da cobertura morta no comportamento dos herbicidas imazaquin e clomazone

Experimentos de campo e bioensaios em casa-de-vegetação foram realizados para se estudar a influência da cobertura morta de trigo (Triticum aestivum L.) no comportamento dos herbicidas imazaquin {ácido 2-[4,5 dihidro-4-metil-4-(1-metiletil)-5-oxo-1H-imidazol-2-ilo]-3-quinolinacarboxílico} e clomazone {2-[(2-clorofenil)metil]-4,4-dimetil-3-isoxazolidinona}, aplicados em pré-emergência na cultura da soja [Glycine max (L.) Merril], no sistema de plantio direto. O clomazone mostrou evidências de ter sido interceptado pela cobertura morta. A presença da cobertura morta não influiu na retenção do imazaquin, sendo este lixiviado da palha para o solo com as chuvas que ocorreram após a aplicação.

SENSORY ANALYSIS OF A MODEL SYSTEM USING 5'-IMP AND CYSTEINE AT DIFFERENT pH

Sensory analysis was used to get an overall flavour description of a reaction mixtures containing 5'-IMP and Cysteine. Ribose/cysteine systems were used as reference systems. Results from triangle and aroma profiling show a clear correlation between the terms used and the volatile analysis described in literature for these model systems. For instance reactions at pH 3.0 and 4.5 for 5'-IMP/cysteine systems, which were described as "meaty" and "boiled meat" by panellists, presented, in the literature, the higher number of "meaty" compounds in volatile analysis (1, 7, 8, 20) .