SPASMOGENIC NONCHOLINERGIC ACTIVITY OF A DIGESTIVE GLAND HOMOGENATE OF THE AMPHIBIAN SNAIL POMACEA-LINEATA SPIX-1827

The digestive gland of Pomacea lineata, a prosobranch gastropod mollusc inhabiting both fresh water and land, does not contain cholinomimetic compounds as do the glands of species of Aplysia, marine opisthobranch gastropods, in which both acetylcholine and urocanylcholine are present. The only pharmacological action detected for the digestive gland of Pomacea was spasmogenic activity of a crude homogenate containing 0.1 g tissue equivalents on the snail's own esophagus bathed in 10 ml of a physiological solution prepared on the basis of the animal's hemolymph composition. The spamodic activity was not blocked by atropine, bromlysergic acid diethylamide or anthazoline.

Effect of ion reduction of sodium, calcium and potassium on spontaneous contraction of the esophagus of Pomacea lineata SPIX, 1827 (Mollusca-Gastropoda-Prosobranchia)

The invertebrate's musculature still presents many elusive points, especially in molluscs that generally present smooth and cracked fibers with peculiar characteristics. It was found that the molluscs reactions to the ion variation in the bathing are not very clear, mainly in view of the isolated reduction or equivalent of the ions. Suspended in bath, the isolated esophagus of the P. lineata exhibited spontaneous activity. This rhythmic activity was sensitive to the ion variation of the perfusion liquid, evidenced by alterations in the spontaneous contractions. The equivalent reduction of the ion reduced the spontaneous activity, evidenced by the amplitude reduction of the response, besides maintaning an organ contraction, primarily in the reductions below 50%. When the isolated reductions of the Na, Ca or K ion were performed, occurred interference in the spontaneous contractions of the organs, principally in amplitude of the response and maintenance of the contracture in reductions of 50 and 25% of the ion.

The respiratory responses of an amphibious snail Pomacea lineata (spix, 1827), to temperature and oxygen tension variations

1. 1. The respiratory responses of Pomacea lineata to short-term (or acute) exposure to temperature and oxygen tension variations were investigated in animals acclimated to 25°C. 2. 2. The respiratory rates increased with rising temperatures; this increase was sharper between 15 and 25°C than at any other temperature interval; a tendency to a plateau in the RT curve was recorded between 25 and 35°C. 3. 3. All animals survived well to 1 hr exposure to the extreme temperatures used (5 and 40°C). 4. 4. In two different experimental approaches, the animals showed ability to regulate the respiratory rate in declining oxygen tensions, at least down to 10% (70.8 mmHg) oxygen. 5. 5. After 1 hr exposure to hypoxic conditions, P. lineata exhibited the pattern of underpayment of the oxygen debt acquired. 6. 6. Six out of ten animals survived after 40 days in anoxia (100% nitrogen). © 1987.

Avaliação da variabilidade genética em quatro gerações de Eucalyptus urophylla S.T. Blake por meio do marcador molecular RAPD

Molecular markers have gradually replaced morphological markers in population studies. The advantages of molecular markers are the speed and precision of evaluations, mainly for long cycle cultures, where determinate traits can take years to manifest. The principle objectives of this research were to assess variability and genetic distances in four generations of Eucalyptus urophylla and provide data that help with the continued improvement of these materials. The populations can be found at the Experimental Forestry Sciences Station, Anhembi, SP, belonging to the College of Agriculture Luiz de Queiroz of São Paulo University. The initial base population was introduced by seeds collected in indonesia and designated P0 generation. The subsequent segregated generations, derivatives of recombination starting with open pollination, were designated P1, P2, and P3. One hundred and seventy four individual trees representing the four generations were analysed. The RAPD technique allowed the identification of 86 loci that were analysed with the Jaccard Coefficient, generating a genetic similarity matrix, permitting the estimation of genetic distances. The genetic distance of generation PO was 0.3338333, P1 was 0.336824, P2 was 0.40000, and P3 was 0.381093. In percentage terms the genetic distances between individuals grew in relation to base population, being 0.15% for generation P1, 18.93% for P2, and 13.31% for P3. This shows an increase in genetic variability with the advance of the program, despite the selective processes. From this came the belief that the initial base population was resulting from seed collection from isolated trees. These populations, although going through successive selections, had a high cross efficiency through satisfactory pollination, which then permitted genetic variation to increase, the outcome of effective recombination between individuals. Generations P2 and P3 gave a better perspective for the continuance of the improvement program due to the high number of different groups with standard genetic distances of 35%. The selections made between the diverse genetic groups allowed the efficient use of genetic variability evaluation.

Caracterização silvicultural, botânica e avaliação da variabilidade genética por meio do marcador molecular RAPD em um teste de progênies de Eucalyptus urophylla S. T. Blake

Molecular markers have recently been incorporated into genetic improvement programs. They are already considered as powerful tools with several different uses, for instance the monitoring of genetic variability in tree populations. The main objectives of this study were to evaluate genetic variability in Eucalyptus urophylla progenies and together with silvicultural and botanical information, provide assistance to the improvement program. The Eucalypts population is located at the Experimental Forestry Sciences Station, Anhembi, SP, which belongs to the College of Agriculture Luiz de Queiroz. Sixty-nine progenies were analysed representing one individual by family in open pollinated Eucalyptus urophylla trees. The RAPD technique allowed the identification of 72 loci that were analysed using Jaccard's Coefficient generating a genetic similarity matrix to permit estimation of genetic distances. The results obtained showed genetic distance between individuals of 0.40 with 12 groups of genetic variability using a standardised distance of 40%. The progenies showed different bark patterns, allowing the establishment of bark groups. The groups formed based on genetic distances obtained using DNA analysis did not correspond to those based on bark pattern. Genetic selection was simulated in which silvicultural and genetic variability data were linked, thus avoiding excessive variability losses. The simulation of controlled crossings allowed the maximum genetic difference to be obtained linked with height and individual bark roughness.

Avaliação de métodos de escarificação na superação de dormência de chizolobium parahyba (vell.) blake (Fabaceae: caesalpinioideae)

Dormancy caused by the tegument's impermeability to water is a feature of Schizolobium parahyba seeds. So that the best methodology for overcoming the species's dormancy may be determined, the seeds were submitted to mechanical scarification treatments, using sandpaper and scissors, on the opposite side of the hilum. Chemical scarification was also undertaken with sulfuric (H2SO4) and hydrochloric (HCl) acids for 30 minutes. Seeds were distributed in groups of 25 units in four petri plates. The experiment was undertaken in a BOD germination chamber at 25°C and 120 μmol.m^-2.s^-1. Data were used to calculate the germination capacity (G%), the Germination Velocity Index (IVG) and Mean Germination Time (TM). Imbibation curve was also calculated to analyze the dormancy type of the seeds by using the three-phase model where phase FI was completed in 6 hours and FIII was initiated after 12 hours of imbibation. Results show that whereas pre-germinative treatments trigger S. parahyba germination, mechanical scarification is the most effective method to overcome the species's dormancy.

Guatemala, censo experimental de 1970: aplicacion de las tecnicas del profesor William Brass para estimar la fecundidad y la mortalidad

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Costa Rica (Canton Grecia) 1968 y Chile 1960: algunas consideraciones del metodo del profesor William Brass para estimar fecundidad

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Cuatro lecciones de William Brass

Conferencias dictadas por el profesor Brass en visita a CELADE, 2-5 noviembre 1975

Aplicaciones de los metodos para estimar la cabalidad de los registros a partir de la distribucion por edades de las muertes: a).de William Brass; b).de Samuel Preston; resumen del estudio

A la informacion sobre la distribucion por edades en las muertes registradas a partir de la edad de 5 anos en Chile, Costa Rica, Guatemala, Panama y Peru, se aplican los dos metodos propuestos para evaluar la cabalidad de los registros de defunciones. Los resultados obtenidos de aplicar estos metodos se presentan en graficos y cuadros, con aplicaciones hechas en los 5 paises

Bolivia: estimacion de la mortalidad a partir de la distribucion por edades de las muertes, 1951. Metodo de William Brass

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Costa Rica: estimacion de la mortalidad masculina adulta a partir de la orfandad de padre por medio de tecnicas de William Brass

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Determinacion de la mortalidad por medio de las tecnicas de William Brass, con especial referencia al sistema logito

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