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61.
Hirsutella uncinata, collected on follicles of Hakea sp. in New South Wales, Australia, is described as a new anamorph species. The fungus produces stiff, erect, verticillate conidiophores with up to 10 whorls of hooked, phialidic conidiogenous cells that have rough-walled necks. The conidia are subfusiform, flattened on one side and produced in groups of 2-3 in a dense slimy ball at the end of each phialide. Parsimony analysis of aligned internal transcribed spacer rDNA sequences suggests that H. uncinata is closely related to the Cordyceps sinensis complex (Clavicipitaceae, Hypocreales), which includes species with morphologically similar anamorphs. 相似文献
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Luciana F Massa Vivian Bradaschia-Correa Victor E Arana-Chavez 《The journal of histochemistry and cytochemistry》2006,54(6):713-725
Newborn rats were treated with sodium alendronate to study how enamel is formed and the effect of alendronate during early odontogenesis. Ultrastructural analysis combined with high-resolution immunocytochemistry for amelogenin was carried out. Twelve rats were subjected to daily SC injections of sodium alendronate (2.5 mg/kg/day) for 3 days on their dorsal region, whereas three rats were daily injected with saline solution as a control. Molar tooth germs from 3-day-old rats were fixed under microwave irradiation in 0.1% glutaraldehyde + 4% formaldehyde buffered at pH 7.2 with 0.1 M sodium cacodylate. The specimens were left undecalcified, postfixed with osmium tetroxide, dehydrated, and embedded in LR White resin. Ultrathin sections were incubated with a chicken anti-24-kDa rat amelogenin antibody, a secondary antibody, and finally with a protein A-gold complex. Large patches of amelogenin were present over the unmineralized mantle dentin and at early secretory ameloblasts. At more advanced stages, they were also detected at the enamel matrix, as well as in the mineralized dentin, at the periodontoblastic space of the dentinal tubules, and at the predentin. It is likely that the main effect of alendronate at early stages of odontogenesis is the increase of synthesis/secretion of amelogenin, promoting its deposition within the forming dentin and enamel. 相似文献
65.
Vallino M Massa N Lumini E Bianciotto V Berta G Bonfante P 《Environmental microbiology》2006,8(6):971-983
The arbuscular mycorrhizal (AM) status of Solidago gigantea was investigated in a contaminated site of Northern Italy, where the chemical industry ACNA (Associated National Chemical Companies) was active till 1999. To counteract the devastating effects of chemicals and to allow re-vegetation, soil from an uncontaminated area was used to cover the highly polluted hills of the industrial site about 25 years ago. On the basis of the current floristic features, the hill was divided into four areas. Heavy metal content in soil and in plant shoots and roots was determined by chemical analysis. The AM fungal community colonizing S. gigantea was investigated from a morphological and a molecular point of view. All plants were modestly colonized, but the fungal structures within the roots were normal. By PCR-RFLP and sequencing of 18S rDNA, 14 AM fungal types were identified: three of them were present in all the considered areas and nine appeared to be specific to certain areas. Glomus was the predominant AM genus. Our analysis demonstrates the presence and the relatively high level of AM species variety and shows how a remediation programme based on cover-soil has been efficient to restore a community of AM fungi, tolerant enough to proliferate in a still contaminated soil. 相似文献
66.
Shoura MJ Vetcher AA Giovan SM Bardai F Bharadwaj A Kesinger MR Levene SD 《Nucleic acids research》2012,40(15):7452-7464
The Cre-recombination system has become an important tool for genetic manipulation of higher organisms and a model for site-specific DNA-recombination mechanisms employed by the λ-Int superfamily of recombinases. We report a novel quantitative approach for characterizing the probability of DNA-loop formation in solution using time-dependent ensemble Förster resonance energy transfer measurements of intra- and inter-molecular Cre-recombination kinetics. Our method uses an innovative technique for incorporating multiple covalent modifications at specific sites in covalently closed DNA. Because the mechanism of Cre recombinase does not conform to a simple kinetic scheme, we employ numerical methods to extract rate constants for fundamental steps that pertain to Cre-mediated loop closure. Cre recombination does not require accessory proteins, DNA supercoiling or particular metal-ion cofactors and is thus a highly flexible system for quantitatively analyzing DNA-loop formation in vitro and in vivo. 相似文献
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Predation shapes many fundamental aspects of ecology. Uncertainty remains, however, about whether predators can influence patterns of temporal niche construction at ecologically relevant timescales. Partitioning of time is an important mechanism by which prey avoid interactions with predators. However, the traits that control a prey organism's capacity to operate during a particular portion of the diel cycle are diverse and complex. Thus, diel prey niches are often assumed to be relatively unlikely to respond to changes in predation risk at short timescales. Here we present evidence to the contrary. We report results that suggest that the anthropogenic depletion of daytime active predators (species that are either diurnal or cathemeral) in a coral reef ecosystem is associated with rapid temporal niche expansions in a multi-species assemblage of nocturnal prey fishes. Diurnal comparisons of nocturnal prey fish abundance in predator rich and predator depleted reefs at two atolls revealed that nocturnal fish were approximately six (biomass) and eight (density) times more common during the day on predator depleted reefs. Amongst these, the prey species that likely were the most specialized for nocturnal living, and thus the most vulnerable to predation (i.e. those with greatest eye size to body length ratio), showed the strongest diurnal increases at sites where daytime active predators were rare. While we were unable to determine whether these observed increases in diurnal abundance by nocturnal prey were the result of a numerical or behavioral response, either effect could be ecologically significant. These results raise the possibility that predation may play an important role in regulating the partitioning of time by prey and that anthropogenic depletions of predators may be capable of causing rapid changes to key properties of temporal community architecture. 相似文献
70.
H Johnston-Cox M Koupenova D Yang B Corkey N Gokce MG Farb N Lebrasseur K Ravid 《PloS one》2012,7(7):e40584