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1.
Summary A diptych ofLucas Cranach (1472–1553), painted 1502/03 in Viena, Austria, shows a Red Macaw from Brazil.  相似文献   

2.
The hypothesis ofHenriques andFernandes that several Iberian species ofNarcissus (Amaryllidaceae) are tristylous is reconsidered. Contrary to the opinion ofBateman and most subsequent authors, we believe that the available evidence indicates that some populations ofN. triandrus andN. fernandesii, at least, are tristylous; other populations ofN. triandrus are distylous.Hugonia cf.penicillanthemum (Linaceae) from new Caledonia is distylous, but it remains possible that other species ofHugonia are tristylous. The disputed occurrence of heterostyly in S. African species ofBauhinia (Leguminosae),Cleome (Capparaceae) andAneilema (Commelinaceae), and inAgelaea (Connaraceae) is discussed.  相似文献   

3.
The paleobiology of the Cretaceous neoselachian shark,Squalicorax, has largely been based on isolated teeth. We examined partial and nearly complete skeletons of three species ofSqualicorax, S. falcatus (Aoassiz),S. kaupi (Agassiz), andS. pristodontus (Agassiz), that were collected from the U.S.A. These specimens suggest that the total body length (TL) ofS. falcatus typically measured 1.8–2.0 m, and probably did not exceed 3 m. Moderatesized individuals ofS. kaupi andS. pristodontus perhaps measured about 3 m TL. AlthoughS. pristodontus was the largest form among the three species examined, this taxon possessed a set of large jaws (with large but fewer teeth) relative to its body size compared toS. falcatus orS. kaupi. This suggests that tooth size is not an accurate indicator of the TL if one compares oneSqualicorax species to another. Neurocranial features suggest that the vision ofSqualicorax was not as acute as that of a contemporaneous macrophagous lamniform shark,Cretoxyrhina mantelli (Agassiz) , but olfaction ofSqualicorax may have been better thanC. mantelli. The morphology of placoid scales suggests thatSqualicorax was capable of fast swimming. New skeletal data support the view that the feeding dynamics ofSqualicorax was similar to the modern tiger shark (Galeocerdo Müller & Henle). The present data do not allow for exact ordinal placement, but, contrary to some previous interpretations,Squalicorax can be excluded from the Hexanchiformes and Orectolobiformes. The taxon should more appropriately be placed within the Lamniformes or Carcharhiniformes.   相似文献   

4.
Growth ofSelenomonas ruminantium HD4 in medium that contained 21mm d-lactate was stimulated to varying degrees by 10mm l-malate, 10mm fumarate, and 2% (v/v)Aspergillus oryzae fermentation extract (Amaferm). Amaferm treatment caused the greatest growth stimulation. Initial uptake rates (30s) and long-term uptake rates (30 min) ofd-lactate by whole cells ofS. ruminantium were increased in the presence of 10mm l-malate. Amaferm (25 l/ml) also stimulated long-term uptake rates ofd-lactate, whereas fumarate had no effect. Initial uptake ofd-lactate was depressed in the presence of fumarate or Amaferm. When eitherl-malate, fumarate, or Amaferm was included in thed-lactate growth medium, a homosuccinate fermentation resulted and an inverse relationship was observed between growth (protein synthesis) and succinate production. Recent research demonstrated that Amaferm containsl-malate, and this dicarboxylic acid may be involved in stimulatingd-lactate utilization byS. ruminantium.  相似文献   

5.
A taxonomic reevaluation of two little-knownBrimeura taxa,B. fontqueri (Pau)Speta andB. duvigneaudii (L. Llorens)Rosselló et al., has been made.Brimeura fontqueri, described from the Iberian peninsula, has been put into synonymy ofB. amethystina (L.)Salisb., since it could not be distinguished on morphological, anatomical or cytogenetic grounds.Brimeura duvigneaudii, from the Balearic Islands, is closely related toB. amethystina and has 2n=28 chromosomes. It differs from the latter by its naked bulbs lacking dark cataphylls, and its narrower leaves and whitish corollas. Accessory chromosomes are reported for the first time in the genus. Karyological instability (with chromosome numbers ranging from 2n=28 to 42) is reported for a population ofB. fastigiata (Viv.)Chouard. A key to the recognized taxa ofBrimeura is provided.  相似文献   

6.
The metabolism ofl-proline toN-acetyl-d-glucosamine (GlcNAc) during germ tube formation ofCandida albicans (C. albicans) ATCC 1002 was studied. In uptake experiments, 6.9 nmol ofl-[14C]proline were taken up by 1×106 cells during 3 h of incubation at 37°C. The percentage of germ tube formation was 94 under the same condition. The presence of GlcNAc reduced the uptake ofl-proline to 3.0 nmol. The percentage of germ tube formation was 95 in the presence and absence of GlcNAc. The [3H]GlcNAc uptake was 3.0 nmol and was constant whetherl-proline was present or not. After the preparation of a chitin fraction from germ tubes that were labeled withl-[14C]proline, the radioactivity froml-proline was detected in the glucosamine (GlcN) fraction by thin-layer chromatography (TLC). The metabolism ofl-proline to GlcNAc in chitin during germ tube formation was confirmed in this experiment.  相似文献   

7.
Gobius brevis (Agassiz, 1839) was hitherto exclusively based on articulated skeletons. It first appears in the late Early Miocene (late Burdigalian, Karpatian) and is widespread throughout the Middle Miocene. Its previously known zoogeographical distribution was the western Paratethys and the Styrian Basin in Austria. We here report on articulated skeletons ofG. brevis with otoliths in situ from a temporary outcrop at Edenkoben, located in the middle Upper Rhine Graben, Germany. The strata are assigned to the basal part of the Upper Hydrobia Beds. The otoliths in situ are identical with those ofGobius latiformis Reichenbacher, 1992, which is an otolith-based species occurring in the Karpatian and Middle Miocene of the western Paratethys; henceG. latiformis has to be regarded as a younger synonym ofG. brevis (Agassiz, 1839). The skeletons ofG. brevis from Edenkoben differ from other articulated freshwater or brackish water MioceneGobius species in the number of vertebrae, more elongate body shape, and number of fin rays. Also the otoliths ofG. brevis differ in their overall shape from these species. However, the in situ preserved otoliths ofG. brevis in the Edenkoben locality show a more primitive evolutionary stage than the Middle Miocene otoliths ofG. brevis (formerly described asG. latiformis). Thus, the gobiid fishes from Edenkoben belong to the oldest representatives ofG. brevis and must be late Burdigalian in age.Gobius brevis probably migrated into the middle Upper Rhine Graben from the Paratethys area.   相似文献   

8.
V. Labeyrie 《BioControl》1961,6(4):257-263
Summary The layings ofCassida deflorata Suffr. are parasited in southern France byMymaridae (Anaphoidea sp. andFulmekiella ovata soyka),Trichogrammatidae (Monorthochaeta nigra Blood.) andEulophidae (Foersterella flavipes Foerst. andTetrastichus rhosaces Walk.). In the Alpes-Maritimes, two successive generations ofMymaridae andTrichogrammatidae seem to attack the layings ofC. deflorata. In Corsica, parasitism byMymaridae andF. flavipes is very frequent and may be the essential regulating factor of the populations ofCassida. In the other regions that have been studied, although the large number ofCassida imagos appearing in spring show that mortality during the aestivation and hibernation is not the primary factor, it does not seem that the limitation of the populations is essentially caused by the activity of oophagous insects.   相似文献   

9.
Hubert Wilbert 《BioControl》1967,12(2):127-137
Summary It was known from earlier experiments thatRhopalomyzus ascalonicus (Donc.) encapsulated the eggs andRhopalosiphoninus staphyleae (Koch) ssp.tulipaellus Theob. the larvae ofAphelinus semiflavus How., but, on the other hand, the mechanical defence reactions of both aphids against the parasite appeared to be conspicuously weak. These experiments were now extended to the parasiteDiaeretiella rapae (M'Intosh) and to the aphidNeomyzus circumflexus (Buckt.). Also the eggs ofD. rapae were encapsulated byRh. ascalonicus without any exception. N. circumflexus only killed the larvae ofD. rapae andA. semiflavus by encapsulation, but some larvae of the second species remained alive. The defensive behaviour of this host during the approach and the attack byA. semiflavus was markedly less developped than that ofMyzus persicae (Sulz.) and was comparable to the behaviour of the two other aphid species. Probably, the defence behaviour of the investigated aphids was reduced when after phylogenetic development of the blood reaction it had become dispensable.   相似文献   

10.
Immunogens were found associated with particular fractions prepared from spherules ofCoccidioides immitis (Kong, Levine &Smith, 1963) and from yeast cells ofHistoplasma capsulatum (Salvin &Ribi, 1955). However,Blastomyces dermatitidis, another dimorphic systemic fungal pathogen was shown to elicit a minimal immunogenic response in experimental animals (Kong &Levine, 1967). It was therefore deemed pertinent to study factors which might enhance the resistance of mice to infection withB. dermatitidis.  相似文献   

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