Distribuição espacial de imaturos de Phyllocnistis citrella (Lepidoptera, Gracillariidae) nos brotos e nas folhas de laranjeiras, Citrus sinensis var. Valência, mantidas sob dois sistemas de cultivo

A distribuição de imaturos de Phyllocnistis citrella Stainton, 1856 foi avaliada em folhas e em brotos de plantas de Citrus sinensis L. Osbeck var. Valência, no município de Montenegro (29°68'S e 51°46'W), Rio Grande do Sul, Brasil. A presença de ovos, lagartas e crisálidas (vivas e mortas) foi registrada nas folhas, em relação às superfícies abaxial e adaxial e à porção proximal, mediana e distal destas. As folhas que continham ovos, lagartas e/ou crisálidas foram classificadas e numeradas quanto à posição relativa a partir do ápice do broto e foram tomadas medidas no maior comprimento. Lagartas, crisálidas e ovos de P. citrella evidenciaram padrão de distribuição agregado tanto no nível de brotos quanto no de folhas. O comprimento médio das folhas onde ocorreram as pupas era maior do que aquele onde se encontravam as lagartas. Os ovos foram registrados em maior proporção no terço mediano das folhas, em ambas superfícies, já as lagartas e crisálidas ocorreram com mais freqüência nos terços mediano e proximal das folhas.

Desenvolvimento larvário de Balanídeos em laboratório - Balanus amphitrite (Var. amphitrite)

É descrita a técnicade criação de balanus amphitrite var. amphitrite em laboratório, sob condições controladas, que permitem observações das mudas, do número de estágios e, ainda são apresentadas as características de cada estágio. Balanus amphitrite amphitrite é criado pela primeira vez em laboratório com sucesso. Dos 200 Nauplii obtidos da eclosão dos ovos das lamelas dos adultos, conseguiu-se a fixação de 120 cypris e o crescimento de 78 Balanus pelo período de três meses. A alimentação usada foi Cyclotella nana, proveniente do New York Aquarium. A fase larvária de Balanus amphitrite amphitrite consiste de seis estágios de Nauplii e um estágio de Cypris. A disposição, forma, tamanho, número de setas, sétulas e espinhos diferem entre os 6 estágios. São apresentados todos os detalhes de microanatomia de cada estágio. A setação é critério valioso para a identificação dos Nauplii e pode ser usada para separar certos estágios especiais. A duração dos seis estágios é a seguinte: o primeiro estágio leva, aproximadamente, de 15 a 20 minutos; 2º estágio de 2 até 4 dias a partir do nascimento dos Nauplii; 3º estágio vai até ao 6º dia; 4º estágio é encontrado a partir do 7º dia de eclosão; 5º estágio varia entre o 9º ao 11º dia e, finalmente, o 6º estágio até o aparecimento do Cypris que se faz no 12º dia de criação. O tempo necessário para o completo desenvolvimento larvários em laboratório estende-se de 12 até 14 dias, aproximadamente. O estudo da metamorfose do Cypris, e o crescimento dos Balanídeos foi realizado por um período de tres meses no frasco de criação.

Contribuição ao estudo dos rotíferos brasileiros: synchaeta tremula var. digitata nova variedade

Em 1968 a autora deu a primeira notícia sobre a presença do gênero Synchaeta no Brasil, assinalando a espécie S. neapolitana. Presentemente, em 1972, ela publica a primeira informação sobre a espécie S. tremula com sua nova variedade digitata, distinguível pelas seguintes características, a seguir: Trophii com uncus profundamente digitado, palmado. Esta variedade foi achada na Enseada de Inhaúma (Baía de Guanabara), em águas de regime mesohalino, e regime A-mesossapróbio de poluição orgânica. Esta publicação apresenta uma chave de espécies a fim de separar S. tremula var. digitata das outras espécies e variedades.

Antitumor activity of chemical modified natural compounds

Search of new activity substances starting from chemotherapeutic agents, continously appears in international literature. Perhaps this search has been done more frequently in the field of anti-tumor chemotherapy on account of the unsuccess in saving advanced stage patients. The new point in this matter during the last decade was computer aid in planning more rational drugs. In near future "the accessibility of supercomputers and emergence of computer net systems, willopen new avenues to rational drug design" (Portoghese, P. S. J. Med. Chem. 1989, 32, 1). Unknown pharmacological active compounds synthetized by plants can be found even without this eletronic devices, as tradicional medicine has pointed out in many contries, and give rise to a new drug. These compounds used as found in nature or after chemical modifications have produced successful experimental medicaments as FAA, "flavone acetic acid" with good results as inibitors of slow growing animal tumors currently in preclinical evaluation for human treatment. In this lecture some international contributions in the field of chemical modified compounds as antineoplasic drugs will be examined, particularly those done by Brazilian researches.

Evaluation of the molluscicidal properties of Euphorbia splendens var. hislopii (n. e. b.) (Euphorbiaceae) - 1: experimental test in a lentic habitat

The latex of Euphorbia splendens var. hislopii, at concentrations between 5 to 12 mg/l, kills 100% of the population of Biomphalaria glabrata in a lentic habitat, after 24 h. The lyophilized latex, stocked for 18 months, killed only 34.2% of the snails, at the concentration of 5 mg/l, and 96.0% at 12 mg/l. No lethal effect was observed among Pomacea haustrum exposed to the same concentrations of the molluscicide.

A medium for inducing conversion of Histoplasma capsulatum var. capsulatum into its yeast-like form

Histoplasma capsulatum var. capsulatum is a dimorphic fungus that, under special conditions, converts from its more common mycelial form to a yeast-like form. Achieving this conversion, however, has been problematical for researchers. The present study tested conversion rates in ten Histoplasma capsulatum var. capsulatum strains using seven culture media, four of wich were conventional and three novel. One of our novel media, MLGema, induced complete conversion, of two strains within five days of incubation at 35 degrees centigrades, and of all strains that eventually converted by the time of the second subculturing transfer, under defined experimental conditions. MLGema is also inexpensive and easy to produce.

Evaluation of the molluscicidal property of Euphorbia splendens var. Hispolii (N.E.B.) (Euphorbiaceae): 2. Investigation in lotic habitat

The latex of Euphorbia splendens var. hispolii in 12 ppm concentration (12 mg/l) caused 100% mortality for a Biomphalaria tenagophila population in a lotic habitat after 9 hr of dripfeed application. For sentinel snails, in cages placed at the water surface and buried under 0.10 m, the mortality rates varied with the distance from the application point and were: 100% (0 m); 92.6% (50 m) and 94.7% (100). No lethal effects were observed for the other living species in this habitat (Pomacea haustrum and Poecilia reticulata).

A modified assay for measuring thymocyte co-stimulatory activity

The observation that murine thymocytes increase their proliferation to interleukin 1 (IL-1) in the presence of phytohemagglutinin (PHA) when pre-incubated with interleukin 2 (IL-2) allowed the introduction of a modified assay for the measurement of IL-1 or the search of thymocyte-inducing proliferative activities in biological samples. Pre-incubation of thymocytes for 24 hr with 50 u/ml IL-2, followed by washings, elicited their maximal response to IL-1 in the usual lymphocyte activating factor (LAF) assay. This suggests that sequential events lead to thymocyte activation. The responsiveness is three to five fold greater than, and the total time of assay is the same as that of the LAF assay. Interestingly, pre-incubation with IL-2 renders thymocytes more sensitive than responsive to crude monocyte conditioned media. The use of the MTT colorimetric method for the assessment of thymocyte proliferation, and of the lectin jacalin as a co-mitogen are suggested as alternatives to be used in co-stimulatory assays.

Evaluation of the Molluscicidal Properties of Euphorbia splendens var. hislopii (N.E.B.) Latex: Experimental Test in an Endemic Area in the State of Minas Gerais, Brazil

Following the positive results obtained regarding the molluscicidal properties of the latex of Euphorbia splendens that were corroborated in laboratory and field tests under restricted conditions, a field study was conducted in experimental streams located in an endemic area. After recording the average annual fluctuations of vectors in three streams, a solution of E. splendens latex at 12 ppm was applied in stream A, a solution of niclosamide at 3 ppm that was applied in stream B and a third stream (C) remained untreated for negative control. Applications of E. splendens and niclosamide resulted in a mortality of 100% among the snails collected in the streams A and B. No dead snails were found in the negative control stream. A monthly follow-up survey conducted during three consecutive months confirmed the return of vectors to both experimental streams treated with latex and niclosamide. This fact has called for a need to repeat application in order to reach the snails that remained buried in the mud substrate or escaped to the water edge, as well as, newly hatched snails that did not respond to the concentration of these molluscicides. Adults snails collected a month following treatment led us to believe that they had migrate from untreated areas of the streams to those previously treated

The molluscicidal activity of the latex of Euphorbia splendens var. hislopii on Melanoides tuberculata (Thiaridae), a snail associated with habitats of Biomphalaria glabrata (Planorbidae)

The use of the latex of Euphorbia splendens var. hislopii was considered as an effective control method for Biomphalaria glabrata in Sumidouro, Rio de Janeiro. However, the appearance and expansion of the snail Melanoides tuberculata since August 1997, with the concomitant reduction of the population of B. glabrata suggest that competitive exclusion might be taking place. Depending on the susceptibility of the thiarid to the E. splendens toxin, the natural control that is occurring could be interrupted by the employment of the latex if the planorbid were less susceptible to the toxin. The aim of this study is to investigate the molluscicidal activity of the latex on M. tuberculata. We used 420 M. tuberculata, from Sumidouro. Fourteen different latex concentrations were tested using World Health Organization general methodology. Probit analysis was used for LD90 and LD50 determination. The LD50 was 3.57 mg/l and LD90 was 6.22 mg/l. At the highest concentration (10 mg/l) there was no survival. No significant differences among replicas (chi2 = 8.31; gl = 13; p > 0.05) were found. The LD90 dose for M. tuberculata was 13.8 times greater than that for B. glabrata, so that the molluscicide in the presence of the thiarid may have a synergic effect on reduction of Biomphalaria populations.