Comment on "Protein sequences from mastodon and Tyrannosaurus rex revealed by mass spectrometry"

We used authentication tests developed for ancient DNA to evaluate claims by Asara et al. (Reports, 13 April 2007, p. 280) of collagen peptide sequences recovered from mastodon and Tyrannosaurus rex fossils. Although the mastodon samples pass these tests, absence of amino acid composition data, lack of evidence for peptide deamidation, and association of alpha1(I) collagen sequences with amphibians rather than birds suggest that T. rex does not.     

Insight in the PCB-degrading functional community in long-term contaminated soil under bioremediation

Purpose  

A small-scale bioremediation assay was developed in order to get insight into the functioning of a polychlorinated biphenyl (PCB) degrading community during the time course of bioremediation treatment of a contaminated soil. The study was conducted with the aim to better understand the key mechanisms involved in PCB-removal from soils.     

Compatibility with killer explains the rise of RNAi-deficient fungi

The RNA interference (RNAi) pathway is found in most eukaryotic lineages but curiously is absent in others, including that of Saccharomyces cerevisiae. We show that reconstituting RNAi in S. cerevisiae causes loss of a beneficial double-stranded RNA virus known as killer virus. Incompatibility between RNAi and killer viruses extends to other fungal species in that RNAi is absent in all species known to possess double-stranded RNA killer viruses, whereas killer viruses are absent in closely related species that retained RNAi. Thus, the advantage imparted by acquiring and retaining killer viruses explains the persistence of RNAi-deficient species during fungal evolution.     

Long-term fertilization effects on crop yields,soil fertility and sustainability in the Static Fertilization Experiment Bad Lauchstädt under climatic conditions 2001–2010

The Static Fertilization Experiment Bad Lauchstädt (1902) consists of a crop rotation of sugar beets, spring barley, potatoes and winter wheat. Three farmyard manure (FYM) treatments and six mineral fertilizer treatments are combined orthogonally. Comparing the first and last decades, crop yields nearly doubled. In unfertilized plots, yields and N uptake by crops also increased when comparing first and last decades. On average for the decade 2001–2010, N uptake in unfertilized plots amounted 51.6 kg ha^?1. Although soil organic carbon (SOC) levels for unfertilized plots remain almost unchanged, SOC increases slowly in the most highly fertilized treatment, resulting in a gradual widening of differences in SOC between the most extreme treatments to 0.952%. Climate change and increased harvesting and root residues due to rising yields are suggested as an explanation. Except for the plot with the highest application of mineral and organic fertilizer, in all treatments more N was taken up by crops than was applied by fertilizers. Higher FYM input leads to more unfavourable N balances because N release from FYM cannot be controlled. Considering atmospheric N input, only in the exclusively mineral fertilized treatment is N balanced out. Similar results are found for C balances: the exclusively mineral fertilized treatment shows the most favourable C balance.     

Stickstoffaufnahme und ‐Freisetzung durch Ruderalzönosen auf Dauerbrachen im Mitteldeutschen Trockengebiet

Auf einer selbstbegrünten Dauerbrache ohne Pflegemaßnahmen (seit 1991) wurden in 4–6 wöchigen Abständen die Trockenmasse (TM) und die N‐Mengen im Pflanzenspross und in verschiedenen Streufraktionen untersucht. In Abhängigkeit von der dominierenden Pflanzenart wurden bis zu 2700 g TM/m² (= 270 dt TM/ha) gebildet. Darin waren bis zu 48 g N/m² (=48g N/ha) enthalten. Nach dem Absterben der Pflanzenbestände bildet sich Streu, die sich auf diesem Standort akkumulierte. In Abhängigkeit von der Güllebelastung des Bodens (hohe Belastung, geringe Belastung, unbelastet) wurde das Maximum der Streu‐TM mit 1345, 1506 bzw. 970 g TM/m² nach 4, 5 bzw. 6 Jahren Brachedauer erreicht. Die N‐Mengen in der Streu stiegen bis zum letzten untersuchten Jahr 1995 allmählich an. Die maximalen Jahresmittelwerte betrugen bei hoher Güllebelastung 27, bei geringer Güllebelastung 31 und ohne Gülle 10 g N/m²(= 270, 310 bzw. 100 kg N/ha). Die N‐Freisetzung aus der Streu begann noch im gleichen Jahr. Sie war im Wesentlichen auf der unbelasteten Parzelle nach 2 Jahren, auf den Gülleparzellen nach 3 Jahren abgeschlossen. Zukünftig müssen die Teilprozesse der N‐Freisetzung aus der Streu und ihre Wechselwirkungen sowie der Einbau des unkrautbürtigen? in die Boden‐N‐Fraktionen und die Wiederaufnahme durch die nächsten Pflanzengenerationen intensiver untersucht werden.     

A new approach to kelp mariculture in Chile: production of free-floating sporophyte seedlings from gametophyte cultures of Lessonia trabeculata and Macrocystis pyrifera

Substantial amounts of Macrocystis and Lessonia are traditionally harvested and exported from Chile as raw material for alginate. Because of intense mariculture of abalone (Haliotis ssp.), herbivorous molluscs that feed on brown kelps, pressure on local populations of Macrocystis and Lessonia has increased to critical levels within the past 5 years, strongly supporting efforts to produce algae maricultured biomass. Here, we present our results on the development of new techniques for large‐scale kelp mariculture in Chile. We have abandoned the traditional technique of direct spore seeding onto inoculation lines. Instead, we used gametophyte cultures that were manipulated to enter gametogenesis and to produce synchronous batches of 10⁴–10⁵ embryos. Juvenile sporophytes were cultured under permanent aeration and agitation, floating unattached in contamination‐free glass bottles up to 10 L, plexiglass cylinders and 800 L greenhouse tanks. When holdfast initials were formed at a size of 8 cm, the sporophytes were spliced into Nylon rope fragments and transferred to the sea. Twelve months after initiation of gametogenesis in the laboratory, Macrocystis pyrifera attained 14 m length and 80 kg fresh weight m^?1 line in the sea. For Lessonia trabeculata 6 months after gametogenesis initiation, 0.25 kg fresh weight m^?1 was attained in the sea.     

Spatial correspondence between areas of concentration of Patagonian scallop (Zygochlamys patagonica) and frontal systems in the southwestern Atlantic

It has been hypothesized that the geographical location of scallop beds in extensive shelf regions mirrors hydrographic structures (e.g. frontal systems) that favor the retention/concentration of pelagic larvae. Large, discontinuous concentrations of the Patagonian scallop (Zygochlamys patagonica) are known to have occurred recurrently (for more than 30 yr) at certain geographical locations over the extensive Patagonian shelf. These stocks, exploited since 1996, currently support one of the most important scallop fisheries in the world. Here, we investigate whether those aggregations are spatially coincidental with major frontal systems. Several pieces of information were used: historical survey data documenting the geographic distribution of the Patagonian scallop beds, catch and effort data from the commercial fleet, oceanographic data on frontal systems, and remote sensing imagery. We found that large-scale aggregations do match the location of three major and very different frontal systems in the southwestern Atlantic: the Shelf-Break Frontal System, the Northern Patagonia Frontal System, and the Southern Patagonia Frontal System. We describe the three frontal systems and their associated scallops fishing grounds and discuss which processes can contribute to sustaining the productivity of the scallop grounds in each case.