BackgroundAmong the various biochemical markers, fatty acids or lipid profiles represent a chemically relatively inert class of compounds that is easy to isolate from biological material. Fatty acid (FA) profiles are considered as chemotaxonomic markers to define groups of various taxonomic ranks in flowering plants, trees and other embryophytes.ResultsThe fatty acid profiles of 2076 microalgal strains from the culture collection of algae of Göttingen University (SAG) were determined in the stationary phase. Overall 76 different fatty acids and 10 other lipophilic substances were identified and quantified. The obtained FA profiles were added into a database providing information about fatty acid composition. Using this database we tested whether FA profiles are suitable as chemotaxonomic markers. FA distribution patterns were found to reflect phylogenetic relationships at the level of phyla and classes. In contrast, at lower taxonomic levels, e.g. between closely related species and even among multiple isolates of the same species, FA contents may be rather variable.ConclusionFA distribution patterns are suitable chemotaxonomic markers to define taxa of higher rank in algae. However, due to their extensive variation at the species level it is difficult to make predictions about the FA profile in a novel isolate.

Although temporal heterogeneity is a well-accepted driver of biodiversity, effects of interannual variation in land-use intensity (LUI) have not been addressed yet. Additionally, responses to land use can differ greatly among different organisms; therefore, overall effects of land-use on total local biodiversity are hardly known. To test for effects of LUI (quantified as the combined intensity of fertilization, grazing, and mowing) and interannual variation in LUI (SD in LUI across time), we introduce a unique measure of whole-ecosystem biodiversity, multidiversity. This synthesizes individual diversity measures across up to 49 taxonomic groups of plants, animals, fungi, and bacteria from 150 grasslands. Multidiversity declined with increasing LUI among grasslands, particularly for rarer species and aboveground organisms, whereas common species and belowground groups were less sensitive. However, a high level of interannual variation in LUI increased overall multidiversity at low LUI and was even more beneficial for rarer species because it slowed the rate at which the multidiversity of rare species declined with increasing LUI. In more intensively managed grasslands, the diversity of rarer species was, on average, 18% of the maximum diversity across all grasslands when LUI was static over time but increased to 31% of the maximum when LUI changed maximally over time. In addition to decreasing overall LUI, we suggest varying LUI across years as a complementary strategy to promote biodiversity conservation.

Purpose: Although unequivocal evidence has shown the prognostic relevance of circulating tumor cells (CTC) in the peripheral blood of patients with metastatic breast cancer, less evidence is available for the prognostic relevance of CTCs at the time of primary diagnosis.Experimental Design: We conducted a pooled analysis of individual data from 3,173 patients with nonmetastatic (stage I-III) breast cancer from five breast cancer institutions. The prevalence and numbers of CTCs were assessed at the time of primary diagnosis with the FDA-cleared CellSearch System (Janssen Diagnostics, LLC). Patient outcomes were analyzed using meta-analytic procedures, univariate log-rank tests, and multivariate Cox proportional hazard regression analyses. The median follow-up duration was 62.8 months.Results: One or more CTCs were detected in 20.2% of the patients. CTC-positive patients had larger tumors, increased lymph node involvement, and a higher histologic tumor grade than did CTC-negative patients (all P < 0.002). Multivariate Cox regressions, which included tumor size, nodal status, histologic tumor grade, and hormone receptor and HER2 status, confirmed that the presence of CTCs was an independent prognostic factor for disease-free survival [HR, 1.82; 95% confidence interval (CI), 1.47-2.26], distant disease-free survival (HR, 1.89; 95% CI, 1.49-2.40), breast cancer-specific survival (HR, 2.04; 95% CI, 1.52-2.75), and overall survival (HR, 1.97; 95% CI, 1.51-2.59).

Biological soil crusts (BSCs) are found in all dryland regions of the world, including the polar regions. They are also known to occur in the southern African region. Although there were a number of case studies on BSCs from that region, we did not know if they are a normal part of the vegetation cover or just a phenomenon that occasionally occurs here and there. In order to investigate diversity, distribution patterns, and the driving factors of both, we followed a random sampling system of observatories along a transect, stretching from the Namibian-Angolan border down south to the Cape Peninsula, covering seven different major biomes. Biological soil crusts were found to occur in six out of seven biomes. Despite the fact that soil-dwelling algae occurred in the Fynbos biome, crust formation was not observed for hitherto unknown reasons. Seven BSC types were distinguished on the basis of morphology and taxonomic composition: three of them were cyanobacteria-dominated, one with additional chlorolichens, two with bryophytes, one hypolithic type restricted to quartz gravel pavements, and the unique lichen fields of the Namib Desert. Besides 29 green algal species in 21 genera, one heterokont alga, 12 cyanolichens, 14 chlorolichens, two genera of liverworts, and three genera of mosses, these crusts are positioned among the most diverse BSCs worldwide mainly because of the unusual high cyanobacterial species richness comprising 58 species in 21 genera. They contribute considerably to the biodiversity of arid and semi-arid bioregions. Taxonomic diversity of cyanobacteria was significantly higher in the winter rain zone than in the summer rain zone (54 versus 32 species). The soil photosynthetic biomass (chlorophylla/m2), the carbon content of the soil and the number of BSC types were significantly higher in the winter rain zone (U27, 29=215.0, p=0.004 [chla]; U21, 21=135.0, p=0.031 [C]; U27, 29=261.5, p=0.028 [BSC types]; excluding the fog-dominated Namib biome). The winter rain zone is characterized by a lower precipitation amount, but a higher rain frequency with the number of rainy days more evenly distributed over the year. The dry period is significantly shorter per year in the winter rain zone (U8, 9=5.0, p=0.003). We conclude that rain frequency and duration of dry periods rather than the precipitation amount is the main factor for BSC growth and succession. Nitrogen content of the soils along the transect was generally very low and correlated with soil carbon content. There was a weak trend that an increasing proportion of silt and clay (<0.63 mm) in the soil is associated with higher values of BSC chlorophyll content (Pearson correlation coefficient=0.314, p=0.237). Furthermore, we found a significant positive correlation between silt and clay and the number of BSC types (Pearson correlation coefficient=0.519, p=0.039), suggesting that fine grain-size promotes BSC succession and their biomass content. Lichens and bryophytes occurred in BSCs with lower disturbance frequencies (e.g. trampling) only. Crust thic...

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