Influência das condições hídricas do solo e da temperatura na sobrevivência e alimentação de oncometopia facialis (hemiptera: cicadellidae) em "seedlings" de citros/ / Influence of soil water conditions and temperature on survival and feeding of oncometopia facialis (hemiptera: cicadellidae) on citrus seedlings

RESUMO O comportamento alimentar de cigarrinhas vetoras de Xylella fastidiosa, agente causal da clorose variegada dos citros, pode influenciar sua eficiência de transmissão. Avaliou-se a influência das condições hídricas do solo e da temperatura ambiente na sobrevivência e alimentação do vetor Oncometopia facialis (Hemiptera: Cicadellidae) em "seedlings" de laranjeira doce (Citrus sinensis).O estudo foi realizado em câmara de crescimento, simulando-se condições de temperatura média e de fotofase de verão (24º C e 13h) e de inverno (19º C e 11h) da região Central do Estado de São Paulo. As plantas foram submetidas a dois regimes hídricos: capacidade de campo e déficit hídrico. A sobrevivência de O. facialis foi menor quando mantida em "seedlings" sob déficit hídrico, independentemente das condições de temperatura ("verão" ou "inverno"). A taxa de ingestão de seiva, medida indiretamente pela excreção de "honeydew", foi maior nos tratamentos mantidos em capacidade de campo para as duas condições de temperatura. Comprovou-se, então, que o déficit hídrico do solo reduz a sobrevivência e a taxa de alimentação de O. facialis em "seedlings" de citros. Os resultados sugerem uma menor adequação da planta cítrica às cigarrinhas durante épocas mais secas do ano.

ABSTRACT The feeding behavior of the leafhopper vectors of Xylella fastidiosa, the causal agent of Citrus Variegated Chlorosis, can influence its transmission efficiency. The influence of soil water conditions and environmental temperature on survival and feeding behavior of the leafhopper Oncometopia facialis (Hemiptera: Cicadellidae) was evaluated on sweet orange (Citrus sinensis) seedlings. This study was carried out in a growth chamber adjusted for mean temperature and photophase of summer (24º C and 13h) and winter (19º C and 11h) seasons in the Central Region of Sao Paulo State. The plants were submitted to two soil water treatments: field capacity and water deficit. The survival of the O. facialis was lower on seedlings under water deficit, regardless of the temperature conditions (summer or winter). The sap ingestion rates, which were indirectly measured by the honeydew excretion, were higher on seedlings under field capacity for both temperature conditions. This study shows that soil water deficit reduces leafhopper survival and ingestion rates on citrus seedlings, thus providing evidence that host plant suitability to the vector is affected during the dry season.

A galantamina no tratamento da doença de Alzheimer's: da pesquisa ao paciente / Galantamine in the treatment of Alzheimer disease: from research to the patient

A doença de Alzheimer (DA) é uma doença neurodegenerativa progressiva, que representa um sério problema para saúde pública, particularmente nos países industrializados, onde a população de idosos vem crescendo de modo acentuado. O tratamento da doença, além de sintomático, visa retardar a progressão das deterioração mental dos pacientes. Recentemente, com bases no seu mecanismo de ação duplo, a galantamina foi adicionada ao arsenal terapêutico para tratamento da DA. Além de atuar como um anticolinesterásico fraco, a galantamina, associando-se diretamente a um sítio de ligação localizado nas subunidades alfa dos receptores nicotínicos, também age como "ligante potencializador alostérico" (LPA/APL) da atividade desses receptores. Esta revisão tem como objetivo central discutir as bases fisiopatológicas que levaram à introdução da galantamina na clínica para o tratamento de pacientes portadores da DA. Para tanto, apresenta uma abordagem geral dos clínicos da doença, incluído não somente uma descrição breve dos sintomas e diagnósticos da doença, como também um resumo dos processos celulares e moleculares alterados durante o curso da mesma. Ênfase é dada à hipótese colinérgica, que assume que a progressão da doença está associada à hipoatividade das funções colinérgicas, especialmente daquelas mediadas pelos receptores nicotínicos neuronais do cérebro. Estudos recentes indicam que pode haver uma relação causal entre a hipofunção colinérgica nicotínica no cérebro e a doença de Alzheimer. É com base nessa hipótese e na descoberta laboratorial da ação LPA/APL da galantamina sobre os receptores nicotínicos, que este alcalóide, originalmente isolado do bulbo da Galanthus nivalis, foi recentemente introduzido em vários países para o tratamento da DA

Multiplication and Movement of a Citrus Strain of Xylella fastidiosa Within Sweet Orange.

Populations of cultivable cells of a citrus variegated chlorosis (CVC) disease strain of Xylella fastidiosa in stems and leaf veins of sweet orange (Citrus sinensis (L.) Osbeck) seedlings were estimated by dilution plating at 1, 2, 4, 8, and 16 weeks after needle inoculation. Cell populations ranged from log 4 to log 5 CFU/g of tissue after 1 week and increased to log 5 to log 7 CFU/g (median log 6) after 8 to 16 weeks. Recovery of greater than log 5 CFU/g from stem nodes distal to the inoculation site indicated systemic movement of the bacteria. Foliar symptoms in inoculated seedlings first appeared after 8 weeks. Population estimates from leaf veins of CVC-affected trees in citrus groves were in the same range but slightly lower (average log 5.8 CFU/g). X. fastidiosa was isolated from citrus more efficiently in periwinkle wilt-GelRite (PWG) and periwinkle wilt (PW) media than in charcoal-yeast extract with ACES buffer (BCYE) medium The relatively lower populations of cultivable cells of X. fastidiosa in citrus with CVC symptoms, compared with those reported in grapevines with Pierce's disease, suggest that most cells of X. fastidiosa within symptomatic citrus may be dead, explaining in part the low rates of vector transmission from citrus to citrus.

Pyrazole, an alcohol dehydrogenase inhibitor, has dual effects on N-methyl-D-aspartate receptors of hippocampal pyramidal cells: agonist and noncompetitive antagonist.

Electrophysiological and biochemical studies demonstrated that pyrazole, an inhibitor of alcohol dehydrogenase and a proposed therapeutic agent for treatment of alcoholic intoxication, activated and blocked the N-methyl-D-aspartate (NMDA) receptor and did not interact significantly with the end-plate nicotinic acetylcholine receptor (AChR). Pyrazole, at concentrations as low as 0.5 microM, applied to outside-out patches excised from the membrane of cultured rat hippocampal neurons, elicited single-channel currents of 48 pS which were blocked by DL-2-amino-5-phosphorovaleric acid, a competitive antagonist of NMDA. In addition, binding studies showed that pyrazole displaced 1-(cis-2-carboxypiperidine-4-yl)methyl-1-phosphoric acid from the agonist recognition site of the NMDA receptor in a concentration-dependent manner and enhanced the binding of (+)-5-methyl-10,11-dihydro-5H- dibenzo[a,d]cyclohepten-5,10-imine to this complex. These data indicate that pyrazole is an agonist at NMDA receptors. However, at higher concentrations, open and burst times as well as the frequency of single-channel currents activated by pyrazole were reduced significantly, a finding which suggests that this compound is also an open channel blocker. In agreement with these results, it was shown biochemically that pyrazole was able to stimulate influx of Ca++ into rat brain microsomes via NMDA receptors and on the other hand to block the influx of Ca++ induced by NMDA. Pyrazole was unable to affect the neuromuscular transmission of frog sartorius muscle-sciatic nerve preparations. Additionally, pyrazole did not interact either with the agonist recognition site or with noncompetitive sites of the AChR. However, this drug had a very weak agonist-like action on the AChR of the Torpedo electric organ, most likely via binding sites different from those described previously for acetylcholine. Therefore, the therapeutic efficacy of pyrazole may be related at least in part to its effects on the NMDA receptor. Furthermore, this compound, because of the small size and rigidity of its molecular structure, becomes a promising drug for the study of the NMDA receptor. Indeed its use may allow a better understanding of the physiological and pathological processes involving this receptor.

Pharmacological screening of plants recommended by folk medicine as anti-snake venom--I. Analgesic and anti-inflammatory activities.

We have observed that several plants used popularly as anti-snake venom show anti-inflammatory activity. From the list prepared by Rizzini, Mors and Pereira some species have been selected and tested for analgesic activity (number of contortions) and anti-inflammatory activity (Evans blue dye diffusion--1% solution) according to Whittle's technique (intraperitoneal administration of 0.1 N-acetic acid 0.1 ml/10 g) in mice. Previous oral administration of a 10% infusion (dry plant) or 20% (fresh plant) corresponding to 1 or 2 g/kg of Apuleia leiocarpa, Casearia sylvestris, Brunfelsia uniflora, Chiococca brachiata, Cynara scolymus, Dorstenia brasiliensis, Elephantopus scaber, Marsypianthes chamaedrys, Mikania glomerata and Trianosperma tayuya demonstrated analgesic and/or anti-inflammatory activities of varied intensity.

Anti-inflammatory properties of new bioisosteres of indomethacin synthesized from safrole which are sulindac analogues.

The anti-inflammatory activities of new compounds (I, II, III and IV) synthesized in 30% overall yield from the abundant natural product safrole, the principal chemical constituent of the oil of sassafras (Ocotea pretiosa, Lauraceae), were determined in mice. The synthesis of these new indenyl-acetic acids (I and II) and indenyl-propionic acids (III and IV) was based on the minimal structural features of non-steroid anti-inflammatory agents of the aryl- or heteroarylcarboxylic acid group. The compounds exhibited potencies 4- to 10-fold less than that of indomethacin in inhibiting carrageenan-induced hindpaw edema. In contrast, like sulindac, all the new compounds were more potent than indomethacin in antagonizing writhing pain and increased vascular permeability caused by acetic acid. The results confirm the anticipated bioisosteric relationship between these synthetic derivatives, designed as sulindac analogues, and the classical non-steroidal anti-inflammatory agent, indomethacin.

Anti-inflammatory preoperties of new bioisosteres of indomethacim synthesized from safrole which are sulindac analogues

The anti-inflammatory activities of new compounds (I, II, II and IV) synthesized in 30% overall yield from the abundant natural product safrole, the principal chemical constituent of the oil of sassafras (Ocotea pretiosa, Lauraceae), were determined in mice. The synthesis of these new indenyl-acetic acids (I and II) and indenyl-propionic acids (III and IV) was based on the minimal structural features of non-steroid anti-inflammatory agents of the aryl- or heteroarylcarboxylic acid group. The compounds exhibited potencies 4- to 10-fold less than that of indometacin in inhibiting carrageenan-induced hindpaw edema. In contrast, like sulindac, all the new compounds were more potent than indomethacin in antagonizing writhing pain and increased vascular permeability caused by acetic acid. The results confirm the anticipated bioisosteric relationship between these synthetic derivatives, designed as sulindac analogues, and the classical non-steroidal anti-inflammatory agent, indomethacin