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The ability of Climacodon septentrionalis to immobilize and kill a mycophagous nematode (Aphelenchoides sp.) in vitro is described for the first time. Two isolates produced droplets (20–45 μm in diameter) that formed at the apices
of tall, stalked, and branching secretory cells (700–1,500 μm tall). On 2% modified malt extract agar, nematodes became enveloped
in the droplets, which restricted their ability to move and resulted in complete immobilization and death within several hours
of contact. The rate of decomposition of the nematodes varied considerably, with most individuals persisting for weeks whereas
others were degraded within several days and appeared to be colonized by dense hyphal growth. This study provides the first
documentation of a non-agaricoid fungus producing secretory cells that are able to immobilize nematodes. 相似文献
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Steven Weaver Mary B. Comer Carolyn L. Jahn Clyde A. Hutchison Marshall Hall Edgell 《Cell》1981,24(2):403-411
A set of four clones containing the two adult β-globin genes of the “single” type mouse C57BL/10 (genotype Hbbs/Hbbs) were isolated from a library of cloned restriction fragments. The two genes, designated βs and βt, were physically mapped onto a 32 kb segment of the chromosome carried by the four clones. βs and βt form a stable heteroduplex 1850 bp long, indicating that they are intact and conserved at this level of resolution throughout their length, including their intervening sequences. The βs gene is allelic with the βdmaj gene of the BALB/ c mouse (genotype Hbbd/Hbbd). These two alleles, as well as their surrounding sequences, are highly conserved. In contrast, heteroduplexes of βt with its BALB/c allele, βdmin, revealed three extensive but localized rearrangements. One region of non-homology falls within the large intervening sequence, IVS2. To the 5′ side of the βt/βdmin gene position two unequal substitutions were observed; each results in the net insertion of about 1000 bp into the Hbbd chromosome. The β/βdmin gene position is bracketed by a 1450 bp inverted repeat. One of the 1000 bp substitutions maps within this inverted repeat. 相似文献
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Jason J. Head Gregg F. Gunnell Patricia A. Holroyd J. Howard Hutchison Russell L. Ciochon 《Proceedings. Biological sciences / The Royal Society》2013,280(1763)
Mammals dominate modern terrestrial herbivore ecosystems, whereas extant herbivorous reptiles are limited in diversity and body size. The evolution of reptile herbivory and its relationship to mammalian diversification is poorly understood with respect to climate and the roles of predation pressure and competition for food resources. Here, we describe a giant fossil acrodontan lizard recovered with a diverse mammal assemblage from the late middle Eocene Pondaung Formation of Myanmar, which provides a historical test of factors controlling body size in herbivorous squamates. We infer a predominately herbivorous feeding ecology for the new acrodontan based on dental anatomy, phylogenetic relationships and body size. Ranking body masses for Pondaung Formation vertebrates indicates that the lizard occupied a size niche among the larger herbivores and was larger than most carnivorous mammals. Paleotemperature estimates of Pondaung Formation environments based on the body size of the new lizard are approximately 2–5°C higher than modern. These results indicate that competitive exclusion and predation by mammals did not restrict body size evolution in these herbivorous squamates, and elevated temperatures relative to modern climates during the Paleogene greenhouse may have resulted in the evolution of gigantism through elevated poikilothermic metabolic rates and in response to increases in floral productivity. 相似文献
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