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The online version of this article (doi:10.1186/s13075-016-1087-x) contains supplementary material, which is available to authorized users. 相似文献Background
Although the citric acid fermentation by Aspergillus niger is one of the most important industrial microbial processes and various aspects of the fermentation appear in a very large number of publications since the 1950s, the effect of the spore inoculum level on fungal morphology is a rather neglected area. The aim of the presented investigations was to quantify the effects of changing spore inoculum level on the resulting mycelial morphology and to investigate the physiology that underlines the phenomena. Batch fermentations were carried out in a stirred tank bioreactor, which were inoculated directly with spores in concentrations ranging from 104 to 109 spores per ml. Morphological features, evaluated by digital image analysis, were classified using an artificial neural network (ANN), which considered four main object types: globular and elongated pellets, clumps and free mycelial trees. The significance of the particular morphological features and their combination was determined by cluster analysis. 相似文献Taxonomic distinctness indices measure the taxonomic relatedness among species and have been used for environmental assessment to detect disturbed habitats. This is the first application of the Average Taxonomic Distinctness (Δ+) and Variance in Taxonomic Distinctness (Λ+) indices to the presence/absence data of rotifer communities to examine their sensitiveness in discriminating perturbed environments. The 26 Greek lakes studied spanned a wide range of morphological and physical–chemical characteristics. Δ+ was significantly correlated (P < 0.05) with maximum depth, salinity and trophic state, while Λ+ was correlated only with salinity. The index Δ+ identified lakes characterized by periods of increased salinity. Communities in these lakes were less diverse, consisting of more closely related species as seen by the reduced number of families than other lakes with similar species richness. Lakes identified by Λ+ had a higher community distinctness than expected due to the overrepresentation of the family Brachionidae; they were also characterized by periods of water-level fluctuations. Both indices were unaffected by sampling effort in terms of number of species and sampling visits; whereas Shannon diversity index (H′) was correlated to species number. Also, based on the randomization test, the taxonomic distinctness indices differentiated lakes anthropogenically disturbed based on the expected patterns of diversity of the area.
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