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81.
and
1988. Aspects of the life history of Cercopithifilaria johnstoni (Nematoda:Filarioidea). International Journal for Parasitology 18: 1087–1092. Cercopithifilaria johnstoni (Nematoda:Filarioidea) occurs in the subcutaneous connective tissues of a spectrum of native murid and marsupial hosts in Eastern Australia. Life cycle studies revealed that: (i) microfilaria occur in lymphatic capillaries and extravascular connective tissue of the dermis (= ‘skin-inhabiting’), (ii) ixodid ticks, particularly Ixodes trichosuri, are intermediate hosts in nature, (iii) development from microfilariae to infective third-stage larva occurs only while the tick is off the host, that is, during ecdysis from larva to nymph or from nymph to adult. Transmission of C. johnstoni in a wild population of bush rats (Rattus fuscipes) occurred in summer and winter, and was associated with peaks in the number of larval and/or nymphal stages of ticks on rats. C. johnstoni was transmitted experimentally to bandicoots (Isoodon macrourus, Perameles nasuta), bush rats and laboratory rats (R. norvegicus), indirectly by subcutaneous inoculation of third-stage larvae and directly by tick feeding. The prepatent period was approximately 3 months and the longest duration of microfilariae in the ‘ skin’ was more than 25 months. Dermal and ocular lesions were observed in R. fuscipes. The host-parasite relationship has the potential for development as an inexpensive and practical model for human onchocerciasis. 相似文献
82.
David L. Evans 《Entomologia Experimentalis et Applicata》1986,40(3):209-214
It was suggested by Heinrich that cryptic, palatable caterpillars would adopt foliar foraging techniques which would reduce the chance of their being detected. I wished to test this hypothesis further and to determine the post-discovery tactics. I found that caterpillars of Larentia clavaria pallidat, contrary to expectations, usually rested on upper surfaces of young Althaea setosa leaves but moved to the undersides when exposed to higher light intensities. This species may be effectively concealed by older canopy leaves. These larvae usually responded to predator-like stimuli by assuming a deimatic s form but rarely dropped. Dropping may be infrequent partly because younger caterpillars could not easily relocate the foot plant. I discuss, briefly the implications of host-plant selection. 相似文献
83.
84.
The cytoplasmic resistivities and membrane breakdown potentials of normal (AA), sickle-cell-trait (AS), and sickle (SS) red
blood cells have been measured by the biophysical methodology of resistive pulse spectroscopy over a range of osmolalities.
At isotonicity, the average membrane breakdown potentials are virtually identical for the three types of cells occurring at
about 1150 V/cm. Average isotonic cytoplasmic resistivities are somewhat higher for the SS cells (166.7±7.49 ohm-cm) compared
to the AA (147.6±1.98 ohm-cm) or AS cells (148.7±1.79 ohm-cm). As medium osmolality is varied, the differences in resistive
properties become enlarged, especially at very low and very high osmolalities. At high osmolalities, both types of sickle
cells show a large increase in internal resistivity compared to the normals; at low osmolality, the SS samples exhibit a distinctly
different membrane breakdown characteristic, decreasing in this parameter, whereas the other two groups increase.
Of the 15 SS samples tested, three displayed much higher cytoplasmic resistivities at isotonicity: 218.2±5.25 ohm-cm, compared
to an average of 153.5±3.46 ohm-cm for the other 12. The relationship between these high resistivities and the subfraction
of irreversibly sickled cells in the sample is discussed. 相似文献
85.
Cells subjected to the events occurring before, during, and after freezing and thawing are exposed to major changes in the
osmotic pressure of the surrounding medium; i.e., the osmolalities can exceed 30. An important question in understanding the
mechanisms of injury is whether cells respond as ideal osmometers to these strongly anisotonic solutions. Mouse and bovine
embryos from eight-cell to blastocyst stage were used to investigate the question. They were found to behave as ideal osmometers
at room temperature over a wide range of tonicities; i.e., from four times isotonic to almost 1/3 times isotonic, ideality
being defined by a Boyle-van't Hoff equation. Embryo volumes increased from 40 to 200% of isotonic over this range and survivals
of mouse embryos were unaffected. However, outside this range the membrane apparently becomes leaky and the survival of mouse
embryos drops sharply. Osmolalities rise to high values during freezing and the paper develops the thermodynamic equations
to show how computed cell volumes as a function of subzero temperature can be translated into the Boyle-van't Hoff format
of cell volume as a function of the reciprocal of osmolality. 相似文献
86.
THE ELM DECLINE AT PAWLAW MIRE: AN ANTHROPOGENIC INTERPRETATION 总被引:2,自引:2,他引:0
87.
FLANDRIAN ENVIRONMENTAL HISTORY OF THE ISLE OF MULL, SCOTLAND. 总被引:4,自引:4,他引:0
88.
Clifford A. Siegfried 《Hydrobiologia》1985,122(2):175-180
The life history characteristics, population dynamics and production of Pontoporeia hoyi in Lake George, New York, were studied from May 1981 through October 1982. P. hoyi, in terms of both density and standing crop, is the most prevalent member of the deep water macrobenthos of Lake George. It reproduces in the winter, with young being released in the late winter-early spring. At the southernmost study site, young released in the spring grew to 6–7 mm in length and bred during their first winter. At the remaining sites, P. hoyi required two years to complete its life cycle. This difference in life history characteristics can be related to food availability and temperature differences. The open waters of the south end of Lake George are not only more productive but are also more closely associated with the littoral zone, providing a wealth of bacteria-rich detritus for benthic deposit feeders. The greater food availability in the south basin of Lake George is reflected in significantly larger brood sizes and smaller size at maturity for P. hoyi populations from the south end of the lake.The southernmost study site has significantly greater P. hoyi density and standing crop than all other sites. The cohort of the year dominated density and standing crop at the southern site while the cohort of the previous year dominated standing crop at the other sites. Peak abundance ranged from 600 · m–2 at the north site to 2 900 · m–2 at the south site. Cohort production ranged from 2g · m–2 at the north site to 15g · m–2 at the south site. 相似文献
89.
Jörg U. Ganzhorn Jean Prospère Abraham Marlène Razanahoera-Rakotomalala 《Primates; journal of primatology》1985,26(4):452-463
Two groups ofAvahi laniger were studied in the Forêt de Analamozoatra near Perinet in the eastern rainforest of Madagascar from August to October 1984.
Overlap between the home ranges of neighbouring groups ofA. laniger was minimal. Group size ranged from one to four individuals with a median group size of two. In four out of ten groups a
baby was born between August and September.A. laniger were most active after dusk and before dawn. They had an extended resting period around midnight. Their diet consisted mostly
of leaves from at least 17 different plant species. They also ate flowers. Fruit eating was recorded twice. Leaves eaten had
high contents of protein and sugar but did not contain alkaloids. The concentration of condensed tannins did not differ between
food items and non-food items. There was no indication of competition with other prosimians that might explain their nocturnality. 相似文献
90.
John C. Milani 《International journal of primatology》1985,6(2):193-200
To determine whether gibbons discriminate among songs given by different groups, I conducted a series of experimental playbacks
of recorded Bornean gibbon (Hylobates muelleri)duets. The gibbons did not respond differentially to their own, neighbors’, and strangers’ songs. Failure to show vocal discrimination
may be due to factors associated with the experimental procedure or may indicate that there is no selective advantage gained
by responding differentially under the playback circumstances. 相似文献