12 resultados para spirostreptida


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Millipede gut microbiology and decomposition of faecal pellets over a period of eight weeks were studied in the laboratory. Bacterial numbers, carbon and nitrogen content, pH and weight loss were monitored. Heterotrophic bacteria were the most abundant and reached a peak in the first two weeks of decomposition. The amount of carbon was constant while ammonium nitrogen decreased from 1.51 % to 0.03 % after eight weeksThe pH of the pellets was slightly acidic and did not change much during the course of decomposition. A succession of micro-organisms was observed on decomposing pellets. Zygomycetes were replaced by Ascomycetes after 20 days of decomposition. Decomposition was significantly affected by temperature. The rate of decomposition was highest at 35[degree]C .

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Considering an estimated number of millipedes of approximately 80,000, cytogenetic studies on these animals are rare, as only a total of 70 species have their karyotypes described. The present study reports on the chromosomal number of four Brazilian diplopods of the family Spirostreptidae: Urostreptus atrobrunneus with 2n = 24, XY; Gymnostreptus olivaceus 2n = 12, XY and Alloporus araraquarensis and A. principes, 2n = 18, XY. The C-banding pattern and NOR staining of U. atrobrunneus, G. olivaceus and A. araraquarensis are described. (C) 2008 Elsevier Ltd. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In the present investigation the locomotor and the metabolic activity of Gymnostreptus olivaceus were studied, using 24-hr cycles at different photoperiods and constant temperature and RH. Locomotor activity was studied by the actography method and was reported as coefficients of nocturnalism [CN (N/N + D). 100]. The results showed a nocturnalism coefficient of 98,71% under normal photoperiod conditions and of 29,58% under inverted photoperiod conditions. In constant illumination, the CN of G. olivaceus was 88,22%, and in constant darkness, its rhythm was close to that of the normal photoperiod (CN = 94,92%). The metabolic activity was studied by manometric Warburg respirometry and lit was reported as mu l O-2 . g(-1). h(-1). The respiratory rate of G. olivaceus under normal photoperiod condition was higher at night than during the day (52,52 x 28,76), coinciding with the pattern of nocturnal locomotor activity of the animal. However, under conditions of inverted photoperiod, the millipede maintained its tendency toward a more intense nocturnal respiratory rate (50,35 x 39,14). Similar behaviours were observed under constant illumination and constant darkness, in which G. olivaceus again presented higher nocturnal respiratory rates than diurnal ones(85,84 x 53,48 and 73,18 x 57,0, respectively). The present experimental data suggests the persistence of an endogenous rhythm where the light may not be an important exogenous synchronizer of the activity of G. olivaceus, because it was insufficient to block the start of the biological clock and the natural tendency of higher nocturnal activities of millipedes, principally when the tests were performed in constant illumination or darkness (free-running tests).

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1. The oxygen consumption of the tropical millipede, Pseudonannolene tricolor (Spirostreptida, Pseudonannolenidae) was studied in both male and female animals (body mass varying from 0.242 to 2.802 g) using a Warburg microrespirometer at 25-degrees-C.2. The allometric equation M = a W(b) was used in order to check the metabolic increases with increasing body mass. The b exponents were, respectively, 0.68 for males and 0.60 for females.3. Results are discussed in terms of the meaning of the b values in Diplopoda and animals in general.4. A relationship between volume and body mass in P. tricolor is also reported.

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The first pair of legs in males of some groups of diplopods is modified, having a large coxa and oral projecting prefemoral process; in the family Spirostreptidae (Spirostreptida) this structure has relevance on the genus level. This paper discusses the shape, presence, and absence of the prefemoral process in the genus Pseudonannolene (Pseudonannolenidae, Spirostreptida) and suggests that this structure is an important taxonomic character in this genus and can be used for distinguishing some species.

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Triple staining with fluorochromes (DA/DAPI/CMA) and C-banding were used to characterize the composition of Pseudonannolene strinatii heterochromatin. C-banding showed C+ bands of different labeling intensity on chromosomes 1 and 2 in some cells. Fluorochrome staining revealed DAPI+ regions corresponding to the C-banding pattern, indicating that the heterochromatin of this species is abundant in AT-rich sequences.

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1. 1. Oxygen consumption and its relationship to declining oxygen tension was examined in the tropical spirotreptid millipede, Plusioporus setiger. 2. 2. At 25°C and normoxia, the allometric equations relating the weight-specific oxygen consumption rates and body weight were V ̇O2 = 2.1266 × W-53 for males, and V ̇O2 = 2.0915 × W-64 for females, but no significant difference was detected from the b-values. 3. 3. Plusioporus setiger regulated respiration down to 35.40 mmHg O2 when suddenly exposed to a lowered oxygen tension, or 17.70 mmHg O2, when examined in a stepwise declining oxygen tension. 4. 4. O2 dependence indices ( K1 K2) were relatively low, also expressing regulation, but no relation to size (weight) was recorded. 5. 5. After exposure to hypoxia, P. setiger showed a typical pattern of under repayment, on the return to normoxia. © 1987.

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The mature testicular vesicles of the species Pseudonannolene tocaiensis have three portions: a peripheral portion; a central portion that is typically secretory and between these two an intermediary portion, a lumen filled with spermatozoa. Both secretory and peripheral portions present the same type of cells. The ultrastructural analysis of the peripheral portion suggests it is involved in hormone synthesis. The secretory portion probably contributes to the production of spermatic fluid, compensating for the absence of male accessory glands in this species. (c) 2007 Elsevier Ltd. All rights reserved.