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71.
O. NYBROE, K. EINARSON AND T. AHL. 1996. Growth and viability of Alcaligenes eutrophus JMP134 was studied in laboratory microcosms with 0.2 μ-filtered seawater prior to release in field-based mesocosms. In unamended systems JMP134 did not grow and viability, measured as direct viable counts combined with immunofluorescence microscopy, was 40–50%. Addition of a nitrogen+phosphorus nutrient mixture caused a greater growth response than amendment with a carbon substrate. Amendment with substrate and/or nutrients caused an increase in viability to ca 100% but only for a brief period coinciding with cell proliferation. Hence, Alc. eutrophus JMP134 has a limited survival potential in seawater unless it is supplied with additional nutrients. 相似文献
72.
73.
Disease control by inducers of resistance Induces of resistance open a new way in the search for control. It may be assumed that inducers of resistance will be used more and more in the coming years. 相似文献
74.
J S Ahl J J Brown 《Comparative biochemistry and physiology. A, Comparative physiology》1991,100(1):155-158
1. Ion transport enzyme (Na/K-ATPase) activity in stage III larvae of the brine shrimp, Artemia, remains elevated throughout the stadium when populations are exposed to methoprene in artificial seawater. 2. Infusion of methoprene, juvenile hormone, or methyl farnesoate causes increased Na/K-ATPase activity in homogenates of mid-stadium larvae that would otherwise exhibit low activity. 3. The sensitivity of the enzyme system to extremely low concentrations of the juvenoids suggests that this may be a common mode of action of these compounds. Additionally it suggests that the enzyme may be under the influence of a similar compound present in the larvae. 相似文献
75.
76.
Klaus-Heinrich Müller Christian Ahl Gerhard Hartmann 《Primates; journal of primatology》1997,38(1):69-77
Geophagy was observed 14 times during an 11-month field study on the ecology and behavior of masked titi monkeys (Callicebus personatus melanochir). Geophagy took place in 12 cases on the surface of a leaf-cutting ant mound (Atta spec.). Analysis of chemical composition and natural features of the soils consumed by the monkeys showed elevated concentrations
of several elements. In contrast, a lower concentration of carbohydrates was found in the ant mound sample compared to random
non-ant mound soil samples. No difference in the concentration of clay elements, pH-value or percentage of organic matter
was found between ant mound samples and randomly collected soil samples. Comparison of used versus not used samples failed
to reveal significant clues about function of geophagy. However, chemical and physical properties of soils ingested support
previous hypothesis that this behavior may aid in the adsorbtion of plant toxins. 相似文献
77.
1. Aposematic coloration in prey promotes its survival by conspicuously advertising unpalatability to predators. Although classical examples of aposematic signals involve constant presentation of a signal at a distance, some animals suddenly display warning colours only when they are attacked. 2. Characteristics of body parts suddenly displayed, such as conspicuous coloration or eyespot pattern, may increase the survival of the prey by startling the predator, and/or by signalling unpalatability to the predators at the moment of attack. 3. The adaptive value of such colour patterns suddenly displayed by unpalatable prey has not been studied. We experimentally blackened the red patch in the conspicuous red–white–black hindwing pattern displayed by an unpalatable insect Lycorma delicatula White (Hemiptera: Fulgoridae) in response to predator's attack. 4. There was no evidence that the presence of the red patch increased prey survival over several weeks. We hypothesise that predators generalised from the red–white–black patches on the hindwings of unpalatable L. delicatula to any similar wing display as a signal of unpalatability. Because a higher proportion of males than females stay put at their resting sites, displaying their wings in response to repeated attacks by predators, wing damage was more frequent in males than in females. 5. To our knowledge, this is the first experimental test of an adaptive role of aposematic signals presented by unpalatable prey during sudden displays triggered by direct predatory attack. 相似文献
78.
Iron Bound-Siderophores, Cyanic Acid, and Antibiotics Involved in Suppression of Thielaviopsis basicola by a Pseudomonas fluorescens Strain 总被引:1,自引:0,他引:1
A Pseudomonas fluorescens strain (CHAo) involved in suppression of black root rot caused by Thielaviopsis basicola in the field, inhibited T. basicola when colonizing roots grown under sterile conditions or when grown on culture, media. Under these conditions it produced siderophores (iron chelating compounds), cyanic acid, and several antibiotics. Iron-free siderophores inhibited neither the germination of endoconidia or chlamydospores nor the mycelial growth of T. basicola, but reduced the production of endoconidia. On the contrary, siderophores complexed with Fe3+ strongly inhibited mycelium growth and spore germination; free iron was less toxic than iron-bound siderophores. Therefore, contrary to what was believed to date, siderophores seem to be toxic not because they deplete iron but because they increase its concentration to the point where it becomes highly toxic. Cyanic acid and the antibiotics also inhibited the growth of T. basicola. Whetherall these compounds are involved in disease control in the soil remains, however, to be determined. 相似文献
79.
B B Fuks A I Shapoval I Grzhebin IM 《Biulleten' eksperimental'no? biologii i meditsiny》1991,112(7):78-80
We investigated the phenomenon of increased sensitivity of tumor-bearing mice to endotoxin shock. I/V administration of sera from tumor (EL-4, B16, R815, MOPC-315) bearers or tumoral culture media into intact mice caused the increased sensitivity to lethal action of LPS plus GMDP. Production of TNF in above mice was also significantly increased under the influence of LPS plus GMDP. Sensitivity induced factors in tumor bearing mice sera have mol. weight more than 50 kDa. This action was partially abolished by indomethacin. 相似文献
80.
Patricia Ahl John F. Antoniw Raymond F. White Silvio Gianinazzi 《Plant molecular biology》1985,4(1):31-37
Summary Proteins associated with the hypersensitive response (b-proteins) were purified from variousNicotiana species and compared biochemically and serologically. The method developed to purify proteins b1, b2 and b3 ofN. tabacum cv. Xanthi-nc was used to purify b-proteins present inN. sylvestris (b0, b1 and b3) andN. tomentosiformis (b2), the parental species ofN. tabacum, and b1″ from bothN. glutinosa andN. debneyi. Ultracentrifugation and amino acid analysis of some of these proteins has shown that they are very similar and that they
are all monomers in their native form (mol wt = 15 700 for b0, b1, b2 and b3; mol wt = 13 800 for b1″).
Based on their reactions to an antiserum produced against protein b1 ofN. tabacum cv. Xanthi-nc, 3 serological groups can be recognized which are independent of the source species (I) b0 and b1, (II) b1″ and b2, (III) b3. Thus, proteins in the same serological group but from different species are more closely related than the b-proteins in
different serological groups but present in the same species. The implication of this site on the possible phylogeny of b-proteins
is discussed.
Serological tests confirmed the b-protein present as a constitutive component in the virus resistant interspecific hybrids
ofN. glutinosa ×N. debneyi as protein b1″. 相似文献