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41.
Third-stage larvae of the genus Anisakis from the fish Leionura atun (Trichiuroidei: Perciformes) form a new cuticle and moult in vitro in about 72 h. If the culture medium is Krebs-Ringer under 5% carbon dioxide in air at 37°C, relatively few moult and survival is poor. But more moult and survival is enhanced if worms are incubated in tissue culture medium 199, even if the gas phase is air, although they moult more quickly if it contains 5% carbon dioxide. In both Krebs-Ringer and 199 the benefits of high concentrations of carbon dioxide only accrue if the gas is present during the first 40 h of incubation. Worms do not feed in these media until they have moulted. 相似文献
42.
Structural and functional dynamics of oogenesis in Glossina austeni: vitellogenesis with special reference to the follicular epithelium. 总被引:2,自引:0,他引:2
Morphological changes of the oocyte, follicle cells and nurse cells of the ovaries of the viviparous fly Glossina austeni during vitellogenesis and postvitellogenesis are outlined. During vitellogenesis, material is pinocytosed and incorporated into yolk spheres by subsequent fusions. Various lines of evidence are presented that indicate much of this material is derived from the follicular epithelium. The ultrastructure of the follicular cells throughout the 9 day cycle and their role in protein synthesis is presented. Subsequent to vitellogenesis, the follicle cells synthesize the secondary envelopes. 相似文献
43.
Arylsulphatase-A and arylsulphatase-B heterogeneity in normal and cancer patient urine was investigated using high resolution agarose isoelectricfocusing. Normal urine contained up to nine forms of arylsulphatase-A activity with isoelectric points from 4.45 to 5.43 and at least 5 forms of arylsulphatase-B between 8.58 and 9.15 along with a broad zone of activity between pH 6.5 and 7.6. Although cancer patients had significantly higher levels of arylsulphatase-A and arylsulphatase-B activity, their pattern of activity was essentially the same as for the normals with only minor quantitative differences in some peaks. 相似文献
44.
R.M. Warwick J.T. Davey J.M. Gee C.L. George 《Journal of experimental marine biology and ecology》1981,56(1):23-31
Gobies, Pomatoschistus microps (Krøeyer), were introduced to a series of cages on an estuarine mud-flat during the period in which the cover of Enteromorpha sp. was declining. They fed selectively on the grazers which either ingested Enteromorpha directly or browsed on micro-organisms attached to it and, therefore, significantly affected the breakdown rate of the alga. It is suggested that the balance between grazers and their predators may be at least partially responsible for the irregular development of Enteromorpha on estuarine mud-flats from year to year. 相似文献
45.
Peritoneal cells harvested from mice injected with Salmonella enteritidis or thioglycollate released large amounts of galactosyltransferase (GT), but not sialyltransferase, into their culture supernatants. Maximum release of GT (using ovalbumin as acceptor) occurred from cells harvested 2-4 days after primary injection, but little GT was released from cells elicited by a secondary injection of salmonella or ovalbumin in sensitised mice or during intraperitoneal allogeneic reactions. Enzyme release in culture did not parallel GT levels in serum. Most enzyme was released by large, poorly adherent, macrophage-enriched, Fc receptor-bearing peritoneal cells of low density. Normal monocytes, bone marrow cells, and platelets also produced large amounts, and normal spleen cells or polymorphonuclear leukocytes moderate amounts, of GT. Lymphocytes, dead cells, mast cells, red blood cells, or whole populations of lymph node and thymus cells released very low levels of enzyme. Very little GT was bound to the cell surface and was not passively absorbed from serum or platelets. Release of GT was prevented at 4 degrees C but was not markedly affected by a variety of metabolic inhibitors except pretreatment of the cells with thrombin, which increased release and trypsin which decreased release. 相似文献
46.
GC Wood 《New Zealand journal of zoology.》2013,40(3):186-195
Abstract The Westland petrel (Procellaria westlandica) is an endemic New Zealand species and one of the very few burrowing seabird species still breeding on mainland New Zealand. It nests only on a series of coastal ridgelines near to Punakaiki on the West Coast of the South Island. Between 2002 and 2005, surveys were undertaken at 28 of the 29 known colonies. The area occupied by the colonies was 73 ha; most colonies had fewer than 50 burrows, but six colonies had 201–500 burrows and four colonies had more than 1000 burrows. We find that the current breeding range of Westland petrel and the location of individual colonies are similar to those reported in both the 1950s and 1970s. Based on total burrow counts at 28 colonies and burrow occupancy rates determined by annual monitoring, the annual breeding population is estimated to be between 2954 and 5137 breeding pairs. 相似文献
47.
48.
Draper J.; Davey M. R.; Freeman J. P.; Cocking E. C.; Cox B. J. 《Plant & cell physiology》1982,23(3):451-458
Suspension cell protoplasts of albino Petunia hybrida have beentransformed by isolated Agrobacterium tumefaciens Ti plasmid.Uptake of octopine Ti plasmid (pTiACH5) into protoplasts wasstimulated by poly-L-ornithine and polyethylene glycol (PEG).The frequency and efficiency of transformation of protoplaststo phytohormone autotrophy was compared using the two uptakeagents with various concentrations of plasmid. Transformationwas most efficient with PEG-mediated uptake, 5 µg of Tiplasmid per 106 protoplasts giving a frequency of 6?105.Octopine was not synthesised in any of the transformants afterthe second subculture on hormone-free medium. DNA-DNA hybridisationshowed the presence of DNA homologous to the T-DNA region ofpTiACH5 in all clones analysed. (Received November 9, 1981; Accepted January 29, 1982) 相似文献
49.
Gareth Davey 《Journal of applied animal welfare science : JAAWS》2013,16(2):169-183
Since the 1970s, research about zoo visitors' effects on the welfare of nonhuman animals in captivity has intensified. Numerous studies have shown that characteristics such as visitor presence, density, activity, size, and position are associated with animal behavioral and—to alesser extent physiological—changes. Studies usually interpret these changes as negative (undesirable) or positive (enriching), but it remains unclear whether they significantly impinge on animal welfare. To make confident conclusions about visitors' effects necessitates more studies using (a) a wider range of animal groupings, (b) measures of stress, (c) visitor-animal variables, and (d) other methodological improvements In the meantime, in addition to further research, individual zoos need to emphasize (a) monitoring the stress indicators of their captive animals, (b) observing visitor behavior, and (c) ensuring that staffs are aware of the “visitor effect” concept. 相似文献
50.
We investigated how the legacy of warming and summer drought affected microbial communities in five different replicated long‐term (>10 years) field experiments across Europe (EU‐FP7 INCREASE infrastructure). To focus explicitly on legacy effects (i.e., indirect rather than direct effects of the environmental factors), we measured microbial variables under the same moisture and temperature in a brief screening, and following a pre‐incubation at stable conditions. Specifically, we investigated the size and composition of the soil microbial community (PLFA) alongside measurements of bacterial (leucine incorporation) and fungal (acetate in ergosterol incorporation) growth rates, previously shown to be highly responsive to changes in environmental factors, and microbial respiration. We found no legacy effects on the microbial community size, composition, growth rates, or basal respiration rates at the effect sizes used in our experimental setup (0.6 °C, about 30% precipitation reduction). Our findings support previous reports from single short‐term ecosystem studies thereby providing a clear evidence base to allow long‐term, broad‐scale generalizations to be made. The implication of our study is that warming and summer drought will not result in legacy effects on the microbial community and their processes within the effect sizes here studied. While legacy effects on microbial processes during perturbation cycles, such as drying–rewetting, and on tolerance to drought and warming remain to be studied, our results suggest that any effects on overall ecosystem processes will be rather limited. Thus, the legacies of warming and drought should not be prioritized factors to consider when modeling contemporary rates of biogeochemical processes in soil. 相似文献