Avaliação da variabilidade do Grapevine leafroll-associated virus 1 e 3 por análise de seqüências de nucleotídeos e polimorfismo conformacional de fita simples

As principais espécies de vírus envolvidas na etiologia do enrolamento da folha da videira (Vitis spp.) são Grapevine leafroll-associated virus 1 e 3 (GLRaV-1 e -3). Neste estudo da variabilidade desses vírus, foram amplificados dois fragmentos de DNA (396 bp do GLRaV-1 e 602 bp do GLRaV-3) por RT-PCR, a partir de RNA total extraído de nervuras e pecíolos de videiras infetadas, utilizando-se dois pares de oligonucleotídeos. Os DNAs amplificados foram clonados e reamplificados, a partir dos clones recombinantes, e comparados quanto às diferenças conformacionais das fitas simples desnaturadas (SSCP). Foram observados dois padrões distintos de perfis eletroforéticos para cada vírus, tendo sido seqüenciado pelo menos um clone viral correspondente a cada padrão. As duas seqüências de nucleotídeos obtidas para o GLRaV-1 apresentaram maior homologia (79,8% e 87,4%) com um isolado australiano e as duas seqüências relativas ao GLRaV-3 exibiram maior homologia (75,1% e 81,8%) com um isolado norte-americano. Os resultados demonstraram a ocorrência de seqüências variantes destes vírus nas videiras analisadas.

Narrow-band 1, 2, 3, 4, 8, 16 and 24 cycles/360º angular frequency filters

We measured human frequency response functions for seven angular frequency filters whose test frequencies were centered at 1, 2, 3, 4, 8, 16 or 24 cycles/360º using a supra-threshold summation method. The seven functions of 17 experimental conditions each were measured nine times for five observers. For the arbitrarily selected filter phases, the maximum summation effect occurred at test frequency for filters at 1, 2, 3, 4 and 8 cycles/360º. For both 16 and 24 cycles/360º test frequencies, maximum summation occurred at the lower harmonics. These results allow us to conclude that there are narrow-band angular frequency filters operating somehow in the human visual system either through summation or inhibition of specific frequency ranges. Furthermore, as a general result, it appears that addition of higher angular frequencies to lower ones disturbs low angular frequency perception (i.e., 1, 2, 3 and 4 cycles/360º), whereas addition of lower harmonics to higher ones seems to improve detection of high angular frequency harmonics (i.e., 8, 16 and 24 cycles/360º). Finally, we discuss the possible involvement of coupled radial and angular frequency filters in face perception using an example where narrow-band low angular frequency filters could have a major role.

Effects of sciatic nerve transection on ultrastructure, NADPH-diaphorase reaction and serotonin-, tyrosine hydroxylase-, c-Fos-, glucose transporter 1- and 3-like immunoreactivities in frog dorsal root ganglion

Frogs have been used as an alternative model to study pain mechanisms. Since we did not find any reports on the effects of sciatic nerve transection (SNT) on the ultrastructure and pattern of metabolic substances in frog dorsal root ganglion (DRG) cells, in the present study, 18 adult male frogs (Rana catesbeiana) were divided into three experimental groups: naive (frogs not subjected to surgical manipulation), sham (frogs in which all surgical procedures to expose the sciatic nerve were used except transection of the nerve), and SNT (frogs in which the sciatic nerve was exposed and transected). After 3 days, the bilateral DRG of the sciatic nerve was collected and used for transmission electron microscopy. Immunohistochemistry was used to detect reactivity for glucose transporter (Glut) types 1 and 3, tyrosine hydroxylase, serotonin and c-Fos, as well as nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-diaphorase). SNT induced more mitochondria with vacuolation in neurons, satellite glial cells (SGCs) with more cytoplasmic extensions emerging from cell bodies, as well as more ribosomes, rough endoplasmic reticulum, intermediate filaments and mitochondria. c-Fos immunoreactivity was found in neuronal nuclei. More neurons and SGCs surrounded by tyrosine hydroxylase-like immunoreactivity were found. No change occurred in serotonin- and Glut1- and Glut3-like immunoreactivity. NADPH-diaphorase occurred in more neurons and SGCs. No sign of SGC proliferation was observed. Since the changes of frog DRG in response to nerve injury are similar to those of mammals, frogs should be a valid experimental model for the study of the effects of SNT, a condition that still has many unanswered questions.

Chemical constituents from the stem of Brosimum potabile (Moraceae)

Three coumarins, 5-methoxypsoralene, xanthyletin, and (-)-marmesin, have been isolated from the ethanolic extract of the stem of the Amazonian plant Brosimum potabile. The structures were determined on the basis of NMR analyses and by comparison with spectroscopic data in the literature. The analysis of the hexane fractions by GC-MS in EIMS mode suggested the presence of (1-methylpentyl)-benzene; α,α-dimethyl-4-(1-methylethyl)-benzenemethanol; 1-methyl-3,5-bis(1-methylethyl)-benzene; urs-12-ene; chola-5,22-dien-3β-ol; cholesta-4,6-dien-3β-ol; sitosteryl 9(Z)-octadecenoate; cholesta-5,22-dien-3β-ol; cholesta-4,6,22-trien-3-one; and cholesta-4,22-dien-3-one. NMR data of other hexane fractions indicated the presence of 3β-acetoxy-lup-12,20(29)-diene; 3β-acetoxy-olean-12-ene; 3β-acetoxy-urs-12-ene; and adian-5-ene. All these compounds are first described in B. potabile.

The L-arginine/nitric oxide/cyclic-GMP pathway apparently mediates the peripheral antihyperalgesic action of fentanyl in rats

There are only a few studies on the molecular mechanisms underlying the peripheral antihyperalgesic effect of opioids. The aim of this study was to investigate the molecular bases of the peripheral antihyperalgesic effect of fentanyl in a model of prostaglandin-induced chemical hyperalgesia. Prostaglandin E2 (1.4 nmol) injected into one hind paw of male Wistar rats (200-250 g, N = 6 in each experimental or control group) pretreated with indomethacin (2.5 mg/kg) potentiated the nocifensive response to formalin (1%) injection made 60 min later. Drugs applied locally 30 min after prostaglandin E2 induced the following effects: fentanyl (0.1-1.0 nmol) caused a dose-dependent reversal of the hyperalgesic state, naloxone (2 nmol) co-injected with fentanyl (1 nmol) completely reversed the antihyperalgesic effect, Nomega-nitro-L-arginine (NOARG, 0.05-0.2 µmol) in combination with fentanyl (1.0 nmol) caused a dose-dependent inhibition of the antihyperalgesic effect of fentanyl, co-administration of L-arginine (0.5 µmol) with NOARG (0.2 µmol) plus fentanyl (1.0 nmol) fully restored the antihyperalgesic effect, and the cyclic-GMP phosphodiesterase inhibitor UK-114,542-27 (5-[2-ethoxy-5-(morpholinylacetyl) phenyl]-1,6-dihydro-1-methyl-3-propyl-7H-pyrazolo [4,3-d]-pyrimidin-7-one methanesulfonate monohydrate; 0.5-2.0 µmol) potentiated a subeffective dose of fentanyl (0.1 nmol) in a dose-dependent manner. However, UK-114,542-27 (2.0 µmol) injected alone did not produce this antihyperalgesic effect. Systemically administered fentanyl (1.0 nmol, sc) did not cause antinociception. Taken together, these results support the view that fentanyl reverses prostaglandin E2-induced hyperalgesia, probably by activating an opioid receptor at the periphery, and furthermore the L-arginine/nitric oxide/cyclic-GMP pathway may mediate this peripheral effect of fentanyl.

Ultrastructural alterations of intracellular stages and effects on blood forms of Trypanosoma cruzi induced in vivo by 2-amino-5-(1-methyil-5-nitro-2-imidazolyl)-1,3,4 - Thiadiazole

An electron microscopy study shows that the administration of a single dose (500 mg/kg, p.o.) of 2-amino-5-(1-methyl-5-nitro-2-imidazolyl)-1, 3, 4-thiadiazole induces in mice infected with Trypanosoma cruzi results in degenerative lesions of the intracellular stages. Ultrastructural alterations are detected as early as 6 hours after the drug administration and destruction of the parasites occurs within 18 - 36 hours. Trypomastigotes are cleared from the bloodstream 4 to 6 hours after treatment. The combined effect on both developmental stages is apparently responsible for the in vivo ejfects of this drug which is the most active drug ever tested in our laboratory in experimental Chagas' disease.

Observações sôbre a terapêutica da ascaridiose com o hidroclorato e com o ciclamato de 2,3,5,6 – Tetrahidro - 6 fenil - imidazo (2,1-b) tiazol

Os autores estudam a ação do ciclamato e do cloridrato de 2, 3, 5, 6, - Tetrahidro-6-fenil-imidazo (2,1-b) tiazol no tratamento da ascaridiose. Foram tratados ao todo 84 indivíduos sendo 48 com o cloridrato e 36 com o ciclamato. O índice de cura com o primeiro foi de 83,9% e com o segundo de 76,4%. Nenhuma reação colateral foi observada com o emprêgo do cloridrato sendo que com o ciclamato 53,6 dos pacientes apresentaram sintomas discretos de intolerância. Os índices de cura assemelham-se aos observados com a piperazina que é a medicação clássica para terapêutica da ascaridiose.

Interpretação de resultados analíticos de fósforo pelos extratores Mehlich-1 e Mehlich-3 em solos do Rio Grande do Sul

As soluções extratoras multielementares possibilitam avaliar a disponibilidade de vários nutrientes de plantas no mesmo extrato; dentre estes o P merece especial atenção. As soluções Mehlich-1 (M1) e Mehlich-3 (M3) enquadram-se nesta categoria. Neste estudo, foram comparados os teores de P extraídos por estas soluções em 360 amostras de solos do Estado do Rio Grande do Sul. Os coeficientes de correlação entre os teores de P extraído pelas mesmas indicaram alto grau de associação e de significância. Os teores de P extraído pela solução Mehlich-3 foram, em média, 50 % maiores que os extraídos pela solução Mehlich-1. O teor de argila, entretanto, influenciou a capacidade extrativa de P pela solução Mehlich-3, sendo necessária uma tabela de ajuste para a interpretação dos valores do P extraído por esta solução.

Síntese de novos herbicidas derivados do 1,2alfa,4alfa,5-tetrametil-8-oxabiciclo[3.2.1]oct-6-en-3-ona

In this paper we report the synthesis of biologically active compounds through a [3+4] cycloaddition reaction to produce the main frame structure, followed by several conventional transformations. The 1,2alpha,4alpha,5-tetramethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one (11) obtained from a [3+4] cycloaddition reaction was converted into 1,2alpha,4alpha,5-tetramethyl-6,7-exo-isopropylidenedioxi-8 -oxabicyclo[3.2.1]octan-3-one (13) in 46% yield. This was further converted into the alcohols 1,2alpha,4alpha,5-tetramethyl-6,7-exo-isopropylidenedioxi-8-oxabicyclo[3.2.1]octan-3 alpha-ol (14), 1,2alpha,4alpha,5-tetramethyl-6,7-exo-isopropylidenedioxi-8 -oxabicyclo[3.2.1]octan-3beta-ol (15), 1,2alpha,4alpha,5-tetramethyl-3-butyl-6,7-exo-isopropylidenedioxi-8-oxabicyclo[3.2.1]octan-3 alpha-ol (17), 1,2alpha,4alpha,5-tetramethyl-3-hexyl-6,7-exo-isopropylidenedioxi-8-oxabicyclo[3.2.1]octan-3 alpha-ol (18) and 1,2alpha,4alpha,5-tetramethyl-3-decyl-6,7-exo-isopropylidenedioxi-8-oxabicyclo[3.2.1]octan-3 alpha-ol (19). Dehydration of 17, 18 and 19 with thionyl chloride in pyridine resulted in the alkenes 20, 21 and 22 in ca. 82% - 89% yields from starting alcohols. The herbicidal activity of the compounds synthesized was evaluated at a concentration of 100 µg g-1. The most active compound was 21 causing 42,7% inhibition against Cucumis sativus L.

Síntese de novas fitotoxinas derivadas do 8-oxabiciclo[3.2.1]oct-6-en-3-ona

The [4+3] cycloaddition was utilized in order to prepare 8-oxabicyclo[3.2.1]oct-6-en-3-one (1) derivatives. The correspondent acetonide 6 was converted into several alcohols (11-16). Addition of aryllithium reagents to 6 resulted in 3-(2-fluorophenyl)-6,7-exo-isopropylidenedioxy -8-oxabicyclo[3.2.1]octan-3alpha-ol (11, 72%) and 3-(2,4-dimethoxyphenyl)-6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan -3alpha-ol (16, 20%). The 3-butyl-6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3 alpha-ol (15, 56%) was obtained through a Grignard reaction. Reduction of 6 resulted in 6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3 beta-ol (7, 62%) and 6,7-exo-isopropylidenedioxy-8-oxabicyclo[3.2.1]octan-3 alpha-ol (8, 20%). The alcohols were treated with thionyl chloride in pyridine, and the corresponding alkenes were obtained with 31-80% yield. The effect of these compounds on the development of radicle and aerial parts of Sorghum bicolor was evaluated.

Monoterpenos di-hidroxilados e hidróxi-nitrogenados 1,2 e 1,3 como ligantes quirais em reação de reformatsky assimétrica

This study describes the use of three (-)-alpha-pinene derivatives, one diol-1,2 [(-)-(1R, 2R, 3S, 5R)-2,6,6-trimethylbicyclo[3.1.1]heptane-2,3-diol 4] and two piridine-hydroxy derivatives [(+)-(1R,2S,3R,5S)-2,6,6-trimethyl-3-(2-pyridinylmethyl)bicyclo[3.1.1]heptan-3-ol 7 and (-)-(1R,2S,3R,5S)-2,6,6-trimethyl-3-[2-(2-pyridinyl) ethyl]bicyclo[3.1.1]heptan-3-ol 8]; one diol-1,3 [(-)-(1S,2R,5S)-2-(1-hydroxy-1-methylethyl)-5-methylcyclohexanol 5] derived from (+)-isopulegol 2 and one diol-1,3 [(+)-(1R,2R,5R)-2-(1-hydroxy-1-methylethyl)-5-methylcyclohexanol 6] derived from (+)-neo-isopulegol 3, as ligands in the asymmetric Reformatsky reaction. The best enantiomeric excess of beta-hydroxy ester obtained in the Reformatsky asymmetric reaction was 18% using ligand 6, and the chemical yield of the reactions was 65% on average.

Effect of population densities of Heterodera glycines race 3 on leaf area, photosynthesis and yield of soybean

The effect of Heterodera glycines on photosynthesis, leaf area and yield of soybean (Glycine max) was studied in two experiments carried out under greenhouse condition. Soybean seeds were sown in 1.5 l (Experiment 1) or 5.0 l (Experiment 2) clay pots filled with a mixture of field soil + sand (1:1) sterilized with methyl bromide. Eight days after sowing, seedlings were thinned to one per pot, and one day later inoculated with 0; 1.200; 3.600; 10.800; 32.400 or 97.200 J2 juveniles of H. glycines. Experiment 1 was carried out during the first 45 days of the inoculation while Experiment 2 was conducted during the whole cycle of the crop. Measurements of photosynthetic rate, stomatic conductance, chlorophyll fluorescence, leaf color, leaf area, and chlorophyll leaf content were taken at ten-day intervals throughout the experiments. Data on fresh root weight, top dry weight, grain yield, number of eggs/gram of roots, and nematode reproduction factor were obtained at the end of the trials. Each treatment was replicated ten times. There was a marked reduction in both photosynthetic rate and chlorophyll content, as well as an evident yellowing of the leaves of the infected plants. Even at the lowest Pi, the effects of H. glycines on the top dry weight or grain yield were quite severe. Despite the parasitism, soybean yield was highly correlated with the integrated leaf area and, accordingly, the use of this parameter was suggested for the design of potential damage prediction models that include physiological aspects of nematode-diseased plants.

Alta prevalência do genótipo 1 em portadores de hepatite C crônica em Belo Horizonte, MG

O vírus da hepatite C é caracterizado pela significativa heterogeneidade genética e é atualmente classificado em seis genótipos principais e diversos subtipos. A determinação do genótipo do vírus tem importância na prática clínica para orientar o tratamento dos pacientes portadores de hepatite C crônica. A prevalência dos diferentes genótipos e subtipos do vírus da hepatite C não tem sido amplamente estudada em algumas regiões do Brasil. Neste estudo foram analisadas 788 amostras de pacientes portadores de hepatite C crônica atendidos nos Centros de Referência em Hepatites Virais de Belo Horizonte, entre 2002 e 2006. A genotipagem do vírus foi realizada por seqüenciamento direto da região 5’ UTR. Adicionalmente, foi realizada análise filogenética incluindo todas as variantes genotípicas obtidas. Observou-se alta prevalência do genótipo 1 (78,4%; 1b [40,4%], 1a [37,5%] e 1a/b [0,5 %]), seguida pelo genótipo 3a (17,9%) e pelo 2b (3,1%). Foram identificadas três amostras (0,4%) com o genótipo 2a/c e duas amostras (0,2%) com o genótipo 4. A análise filogenética mostrou a segregação esperada das seqüências obtidas junto às seqüências de referência para os genótipos 1, 2, 3 e 4, exceto em duas amostras do genótipo 1a. A alta prevalência do genótipo 1 (78,4%), encontrada na população de Belo Horizonte é semelhante à previamente descrita em outras cidades, como Rio de Janeiro, mas superior à encontrada em São Paulo e no Sul do país. A presença de raras seqüências atípicas da região 5’UTR sugere a presença de variantes do vírus da hepatite C nesta população.

Occurrence of strongyloidiasis among patients with HTLV-1/2 seen at the outpatient clinic of the Núcleo de Medicina Tropical, Belém, State of Pará, Brazil

IntroductionThis study investigated the occurrence of Strongyloides stercoralis infestation and coinfection with HTLV-1/2 in Belém, Brazil.MethodsS. stercoralis was investigated in stool samples obtained from individuals infected with HTLV-1/2 and their uninfected relatives.ResultsThe frequency of S. stercoralis was 9% (9/100), including six patients infected with HTLV-1 (14.3%), two patients infected with HTLV-2 (11.1%), and one uninfected relative. Two cases of hyperinfestation by S. stercoralis were characterized as HTLV-1.ConclusionsThese results support the need for the routine investigation of S. stercoralis in patients with HTLV-1, in an attempt to prevent the development of severe forms of strongyloidiasis.