Zur Rotatorienfauna Siziliens

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Distribution of Adult Male and Female Baccharis concinna (Asteraceae) in the Rupestrian Fields of Serra Do Cipó, Brazil

Abstract: This study focuses on the sex ratio and spatial distribution of males and females in three populations of the endemic and restricted tropical dioecious shrub, Baccharis concinna (Asteraceae) in the mountainous region of Serra do Cipó, southeastern Brazil. The proportion of female plants in the population at lower elevation (1000 m a.s.l.) was significantly greater than of male plants. At this elevation of P/N and Ca/Al ratios in the soil were also greater indicating better nutritional status of the soils. The concentration of aluminium increased significantly with the elevation ( p < 0.001), perhaps rendering soils less conducive to female plants at higher elevations. Female plants are possibly adversely affected to a greater extent by soil quality than male plants. The spatial distribution of the populations within habitat was tested by the K(t) function, where the neighbourhood of a given individual was defined by a circle with a radius (t) up to 3 m. Despite the strong tendency for aggregation, the distribution of the sexes within habitats was random and the hypothesis was not supported. The independent distribution of the sexes within habitats may be explained by nutrient homogeneity of the soils, as well as by an absence of antagonism between the sexes. Nevertheless, we found a trend for males and females to be aggregated according to their gender.     

Chloride cell responses to long-term exposure to distilled and hard water in the gill of the armored catfish, Hypostomus tietensis (Loricariidae)

The morphological changes in the gill chloride cells of the armored catfish, Hypostomus tietensis , were investigated after 15 days' exposure to either distilled or hard water. The thickness of the water–blood barrier in the lamellae increased significantly in fish kept in distilled water due to the high proliferation of chloride cells. The apical surface of about 68% of chloride cells was sharply reduced by the development of an apical crypt with a sponge-like surface, although no change in the chloride cell fractional area was found. In contrast, H. tietensis kept in Na⁺, Cl⁻ and Ca²⁺ rich water displayed no significant changes in the number of chloride cells or in their apical surface morphology compared with the control fish. Chloride cell response to ion challenge in H. tietensis suggested the involvement of different strategies to maintain homeostasis in ion-poor water, which may be related to the life history of species.     

6(5)CARBOXYFLUORESCEIN AS A TRACER OF PHLOEM SAP TRANSLOCATION

6(5)carboxyfluorescein (6(5)CF), a polar fluorescein with an apparent pK of 6.3, was introduced, as a pH 6.3 solution, into the apoplast of lamina or petioles of mature soybean leaves. Freehand sections were prepared at various times and immediately observed with a fluorescence microscope. 6(5)CF-associated fluorescence appeared in all sink organs, from shoot apex to roots. It was strictly confined to the phloem regions, even after 4 days. Its transport into young leaves ceased at approximately the time they underwent sink-to-source transition. It was never transported between two leaflets of the same leaf. Its transport was interrupted by phloem destruction. All these transport characteristics were highly reproducible, and were paralleled by those of ¹⁴C transport after application of (¹⁴C)sucrose to leaf surfaces. In contrast with 6(5)CF, fluorescein was transported between mature leaves, and between leaflets of the same leaf. It was not restricted to phloem, and often appeared in the xylem region. These results indicate that 6(5)CF can be used to monitor phloem sap translocation in real time, in short- and long-term experiments.     

Comparative study of helminth parasites of fishes from the Mogi Guassu river, collected during expeditions between 1927 and 1985

This paper concerns the parasitism of Nematoda, Trematoda, Acanthocephala and Cestoda from 1027 fishes of 45 species from Mogi Guassu river, examined in the years 1927, 1946, 1947, 1962, 1983 and 1985 as a contribution to the knowledge of the parasitological fauna in 58 years. Thirty two species of nematodes, 21 of trematodes, 3 of acanthocephalans and 2 of cestodes are reported. New hosts are presented for the nematodes Cucullanus pinnai, Spirocamallanus inopinatus and Travnema travnema, for the trematode Pararhipidocotyle jeffersoni and for the acanthocephalan Gorytocephalus spectabilis. New measurements for the trematode Creptotrema lynchy, tables, graphics and a list of the examined hosts with their parasites are presented.     

Evidence of an insulin generated pyruvate dehydrogenase stimulating factor in rat brain plasma membranes

1. The results of this study indicates that the binding of insulin to brain plasma membranes activates a membrane protease which, by a trypsin like mechanism, produces a soluble factor that modulates the PDH behaviour when added to brain mitochondria. 2. The supernatant from brain plasma membranes incubated with 0.5 mg/ml trypsin added to mitochondria increases PDH activity levels and cancels PDH inhibition by NaF, as has already been seen when the plasma membranes are incubated with 25 microU/ml insulin. No such effects are obtained when the incubation is run out with 0.5 mg/ml chymotrypsin. 3. The supernatants from insulin or trypsin treated plasma membranes retain their activating properties on mitochondrial PDH also after dansylation; from these preparations a dansylated active on PDH material was separated by monodimensional chromatography on HPTLC silica Gel plates, using chloroform/1-butanol (93:7 v/v) as a solvent. 4. Insulin incubation of plasma membranes pretreated with protease inhibitors (leupeptin, phenylmethylsulfonylfluoride) or with exogenous trypsin, but not chymotrypsin substrates (esters of arginine and tyrosine) yields an inactive supernatant on PDH. 5. Insulin treated plasma membrane supernatants lose all stimulating properties on PDH after incubation for 1 hr with 2 mg/ml trypsin or chymotrypsin.     

Ultrastructural immunocytochemical study of the massa caudalis of the subcommissural organ-Reissner's fiber complex in lamprey larvae (Geotria australis): Evidence for a terminal vascular route of secretory material

Summary The massa caudalis of the subcommissural organ-Reissner's fiber complex of lamprey larvae (Geotria australis) was studied immunocytochemically at the ultrastructural level by use of the immunoperoxidase-silver methenamine procedure. An antiserum raised against bovine Reissner's fiber was utilized as primary antibody.The caudalmost portion of the central canal and its ampulla caudalis communicate, via wide intercellular spaces in their dorsal wall, with large cavities or lacunae. In addition, distinct openings in the dorsal wall of the ampulla establish an open communication between the latter and the lacunae. The lacunae are lined by slender processes of cells of unknown nature. No junctional complexes can be observed between these cells, which lack a basal lamina. The lacunae communicate with structures resembling blood capillaries, however, they are devoid of a basal lamina. These peculiar vessels, in turn, are in direct communication with characteristic blood capillaries.Reissner's fiber (RF) and its massa caudalis are strongly immunoreactive with the antiserum used. The wide intercellular spaces in the dorsal wall of the central canal and the ampulla, as well as the lumina of the (i) lacunae, (ii) modified vessels and (iii) blood capillaries are filled with a flocculent, strongly immunoreactive material. No immunoreactive material was found outside these structures. Thus, the blood capillaries appear to represent the only final target of RF-material arriving at the ampulla caudalis.Supported by Grant I 38259 from the Stiftung Volkswagenwerk, Federal Republic of Germany, Grant S-85-39 from the Dirección de Investigaciones, Universidad Austral de Chile, and Grant 6027 from Fondo Nacional de Desarrollo Científico y Tecnológico, Chile. The authors express their gratitude to Mrs. Elizabeth Santibáñez and Mr. Julio Lamilla for providing the lamprey larvae and to Mr. Humberto Molina for preparing the three-dimensional drawing