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41.
A bacterial cDNA clone was identified carrying one third of the nucleotides coding for elongation factor EF-1 alpha from the brine shrimp Artemia. The sequence of codons corresponds with the known sequence of amino acids of EF-1 alpha in the region involved.  相似文献   
42.
43.
An examination of four species of Cirsium disclosed the presence of two new flavonoids in C. lineare. The structure of one was 5,4′-dihydroxy-6,7,3′-trimethoxyflavone (cirsilineol) 4′-monoglucoside and the other 5,3′,4′-trihydroxy-6,7-dimethoxyflavone (cirsiliol) 4′-monoglucoside. Luteolin 7-glucoside was found in C. suffultum, and pectolinarin and linarin in C. kamtschaticum and C. pectinellum.  相似文献   
44.
An avian piroplasm, Nuttallia balearicae sp. n., is described from captive Balearica p. pavonina and B. p. gibbericeps. Other avian piroplasms and their validity and taxonomic status are discussed. The possible route of transmission of these parasites is also considered.  相似文献   
45.
Trap sampling over reefs in deep (mean = 20 m) and shallow (mean = 10 m) waters along c. 1500 km of coastline in tropical north‐western Australia during both day and night and in wet and dry periods yielded 23 377 fishes, representing 32 families, 58 genera and 119 species. Individuals of the Serranidae, Lutjanidae, Lethrinidae and Carangidae contributed 88·9% to the total catch. The ichthyofaunal compositions of the Kimberley, Canning and Pilbara bioregions were relatively discrete. Species composition was influenced far more by location (latitude) than by water depth, period and time of day, and underwent a gradational change southwards. The latter change reflected differences in the trends exhibited by the relative abundances of certain species with increasing latitude and the confinement of other species largely to particular regions. The three most abundant species, i.e. Lethrinus sp. 3, Lutjanus carponotatus and Lethrinus laticaudis contributed 34·8, 20·8 and 11·6% to the total catch, respectively. The first species was rarely recorded in the two most northern locations and was abundant in the four most southern locations, whereas the last two species were relatively more abundant in northern than in southern locations. Lutjanus bitaeniatus and Lutjanus johnii were found exclusively at the two locations in the Kimberley region, whereas Abalistes stellatus, Pentapodus emeryii and Lethrinus nebulosus were not caught in this region but were found in both locations of the Canning and Pilbara regions. The species composition in deep and shallow waters at each location almost invariably differed significantly between day and night and between dry and wet periods, with species such as L. bitaeniatus, L. johnii, Lutjanus sebae and A. stellatus being more abundant over deep reefs, whereas L. carponotatus, L. laticaudis, Siganus fuscescens and Lethrinus lentjan were more numerous over shallow reefs. Species such as L. johnii and Lethrinus atkinsoni were relatively more important in night‐time than daytime catches, whereas the reverse applied to Lethrinus lentjan, L. laticaudis and Choerodon cyanodus. Lethrinus sp. 3 and L. laticaudis were relatively more important in catches during the dry than wet period.  相似文献   
46.
Sensitivity to and requirement for iron in Plantago species   总被引:1,自引:0,他引:1  
  相似文献   
47.
Synopsis Experiments were carried out to study the feeding rates of the predator fish Therapon jarbua (Forsk) on mullet juveniles, before and after treatment with DDT. Mullet juveniles treated with a subacute concentration, were refused by the control predators, whereas predators treated with a subacute concentration consumed more mullet juveniles. In the present study crescent perch T. jarbua were exposed to subacute and acute concentrations of DDT, and their behaviour was compared with that of the control predators. There were changes in oriented behaviour and co-ordinated movements, and in feeding, aggression and comfort behaviour of the fish. Inflammation in the gills, and caudal fin serration, were noticed in treated fishes. The findings presented here throw light on fundamental pathways by which pollutants interact with the behaviour of fishes.  相似文献   
48.
Transecting the axons of neurons in the adult superior cervical ganglion (SCG; axotomy) results in the survival of most postganglionic neurons, the influx of circulating monocytes, proliferation of satellite cells, and changes in neuronal gene expression. In contrast, transecting the afferent input to the SCG (decentralization) results in nerve terminal degeneration and elicits a different pattern of gene expression. We examined the effects of decentralization on macrophages in the SCG and compared the results to those previously obtained after axotomy. Monoclonal antibodies were used to identify infiltrating (ED1+) and resident (ED2+) macrophages, as well as macrophages expressing MHC class II molecules (OX6+). Normal ganglia contained ED2+ cells and OX6+ cells, but few infiltrating macrophages. After decentralization, the number of infiltrating ED1+ cells increased in the SCG to a density about twofold greater than that previously seen after axotomy. Both the densities of ED2+ and OX6+ cells were essentially unchanged after decentralization, though a large increase in OX6+ cells occurred after axotomy. Proliferation among the ganglion's total non‐neuronal cell population was examined and found to increase about twofold after decentralization and about fourfold after axotomy. Double‐labeling experiments indicated that some of these proliferating cells were macrophages. After both surgical procedures, the percentage of proliferating ED2+ macrophages increased, while neither procedure altered the proliferation of ED1+ macrophages. Axotomy, though not decentralization, increased the proliferation of OX6+ cells. Future studies must address what role(s) infiltrating and/or resident macrophages play in regions of decentralized and axotomized neurons and, if both are involved, whether they play distinct roles. © 2002 Wiley Periodicals, Inc. J Neurobiol 53: 68–79, 2002  相似文献   
49.
Germination ecology of drupelets of the fig (Ficus carica L.)   总被引:1,自引:0,他引:1  
Abiotic and biotic factors and their effects on germination of fig drupelets were studied. The drupelets germinated between 10oC and 30oC.Constant humidity was necessary for germination and frequent drying out of the substrate was unfavourable. Total darkness for the whole duration of the experiments had a slighly negative effect on germination. The fastest germination occurred at constant humidity and an alternating temperature of 20/30oC with exposure to light for 8 hours (at the higher temperature) and to darkness for 16 hours (at the lower temperature).Natural or artificial removal of drupelets from the syconium guaranteed a high germination percentage, whereas no germination occurred in drupelets left inside the syconium. Hence birds and mammals act as dispersal agents and mediators of germination. As they eat pieces of fig syconium, they free the drupelets from the flesh, eliminating the effect of inhibitors and/or microenvironments with high osmotic pressure inside the syconium. These findings support the hypothesis that germination occurs in autumn or spring depending on the climatic zone in which the species grows.  相似文献   
50.
Two species of fiddler crab, Uca tetragonon(Herbst, 1790) and Uca vocans(Linnaeus, 1758), which belong to the subgenus Gelasimus, dwell on rocky shores and muddy–sandy tidal flats, respectively, in Phuket Is., Thailand. We investigated their feeding ecology in relation to the morphology of their feeding organs: minor food-handling chelipeds and maxillipeds. U. tetragononfed chiefly on rocks covered by filamentous green algae. U. vocansfed on the emerged sand and in shallow water along the shoreline and in pools. While feeding, both crabs made sand pellets beneath their mouthparts and discarded them, indicating that they divided the matter scooped up with their minor chelipeds into edible and inedible fractions by using the maxillipeds in the water passing through their buccal cavity. The morphology of maxillipeds hardly differed between the two species, which means that both species are flotation-feeders. The morphology of their minor chelipeds, however, differed: the tips of the dactyl and pollex were flat in U. tetragononand pointed in U. vocans.When the minor cheliped was closed, U. tetragononhad a hemispherical space in the distal one-fourth of the gape, which was closed by the framing keratin layers and a few setae of the dactyl and pollex. On the other hand, U. vocanshad an ellipsoidal space in the distal half of the gape. We consider these morphological characters to be adaptations to the different feeding substrates for retaining more food-laden sediment. We discuss the role of the setae on the minor chelipeds on the basis of the morphological differences between populations of U. tetragononin Phuket Is. and East Africa where the crab inhabits muddy–sandy tidal flats.  相似文献   
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