Spread of potato virus Y in potato cultivars (Solanum tuberosum L.) with different levels of sensitivity

The aim of this work was to correlate the appearance of the symptoms, multiplication and spread of virus after mechanical inoculation of potato (Solanum tuberosum L.) cultivars showing different levels of susceptibility and sensitivity to Potato virus Y^NTN (PVY^NTN). The potato cultivars used were the resistant cultivar Sante and susceptible cultivars Igor, Pentland squire and Désirée. The spread of the virus PVY^NTN in infected plants was monitored using different methods: DAS-ELISA, tissue printing, immuno-serological electron microscopy and real-time PCR. In all three susceptible cultivars, the virus was detected in the inoculated leaves 4–5 days after inoculation. From there virus spread rapidly, first into the stem, then more or less simultaneously to the upper leaves and roots. Real-time PCR was shown to be very sensitive and enabled viral RNA to be detected in non-inoculated leaves of susceptible cultivar Igor earlier than other methods. Therefore, for exact studies of plant–virus interaction, a combination of methods which detect viruses on the basis of their different properties (coat protein, morphology or RNA) should be used to monitor the spread of viruses.     

Fire-derived charcoal causes loss of forest humus

Fire is a global driver of carbon storage and converts a substantial proportion of plant biomass to black carbon (for example, charcoal), which remains in the soil for thousands of years. Black carbon is therefore often proposed as an important long-term sink of soil carbon. We ran a 10-year experiment in each of three boreal forest stands to show that fire-derived charcoal promotes loss of forest humus and that this is associated with enhancement of microbial activity by charcoal. This result shows that charcoal-induced losses of belowground carbon in forests can partially offset the benefits of charcoal as a long-term carbon sink.     

Shiga toxin-producing Escherichia coli and their bacteriophages as a model for the analysis of virulence and stress response of a food-borne pathogen

Enterohemorrhagic Escherichia coli (EHEC) are a subgroup of Shiga toxin-producing Escherichia coli (STEC) that are able to cause serious food-borne intestinal diseases which can be followed in 5 to 15% by extraintestinal sequelae such as the hemolytic-uremic syndrome (HUS). One of the major pathogenicity factors of EHEC is the production of one or more Shiga toxins (Stx), which act as inhibitors of protein biosynthesis and have profound effects on the signal transduction and immunological response in eukaryotic cells. The stx genes are located in the genome of heterogeneous, lambdoid, functional or cryptic bacteriophages and are expressed during the phage life cycle. Due to the linkage between the phage life cycle and stx expression, STEC and their bacteriophages are useful as a model for the analysis of stress response and virulence of this food-borne pathogen.     

Fragmentation and flow regulation of the world's large river systems

A global overview of dam-based impacts on large river systems shows that over half (172 out of 292) are affected by dams, including the eight most biogeographically diverse. Dam-impacted catchments experience higher irrigation pressure and about 25 times more economic activity per unit of water than do unaffected catchments. In view of projected changes in climate and water resource use, these findings can be used to identify ecological risks associated with further impacts on large river systems.     

Hybridisation in kiwi (Apteryx; Apterygidae) requires taxonomic revision for the Great Spotted Kiwi

Background: Kiwi (Apteryx spp.) are flightless ratites from New Zealand whose numbers and distributions have declined following human arrival. Some of the kiwi ...     

Hormone-sensitive lipase: sequence, expression, and chromosomal localization to 19 cent-q13.3

Hormone-sensitive lipase, a key enzyme in fatty acid mobilization, overall energy homeostasis, and possibly steroidogenesis, is acutely controlled through reversible phosphorylation by catecholamines and insulin. The 757-amino acid sequence predicted from a cloned rat adipocyte complementary DNA showed no homology with any other known lipase or protein. The activity-controlling phosphorylation site was localized to Ser563 in a markedly hydrophilic domain, and a lipid-binding consensus site was tentatively identified. One or several messenger RNA species (3.3, 3.5, or 3.9 kilobases) were expressed in adipose and steroidogenic tissues and heart and skeletal muscle. The human hormone-sensitive lipase gene mapped to chromosome 19 cent-q13.3.     

Major Extractable Organic Compounds in the Biologically Degradable Fraction of Fresh,Composted and Anaerobically Digested Household Waste

The recirculation of plant nutrients from urban areas to agriculture and horticulture and a need to reduce waste disposal by landfilling and incineration are the main reasons for recycling the biologically degradable fraction of household waste. However, before using the recycled material in agricultural and horticultural production it is necessary to make sure that the material does not contain any unwanted contaminants. In general, there is a lack of knowledge about organic contaminants in the degradable fraction of household waste and its compost and anaerobic digestion products. As a first step in a study of organic contaminants in household waste, and as part of the characterization of the degradation processes during composting and anaerobic digestion, the major extractable organic compounds were identified in the biologically degradable fraction of fresh, composted and anaerobically digested household waste. The organic compounds were isolated by supercritical fluid extraction using carbon dioxide as extraction medium. Gas chromatography-mass spectrometry was used for qualitative analyses. Natural products, such as fatty acids, fatty acid esters, n-alkanes, aliphatic alcohols, monoterpenes and triterpenes constituted the major organic components in the waste samples. In addition bis-(2-ethylhexyl) phthalate, frequently used as a plasticizer in polymers, was found in the extracts. In the chromatograms of the extracts of the fresh and composted household waste, fatty acids and fatty acid esters dominated with respect to peak heights and the number of peaks identified. In the anaerobically digested household waste n-alkanes were the dominating compound class. The pattern of the n-alkanes, also found in the fresh waste, possibly indicates a petrogenic origin of these compounds, perhaps caused by contamination during the collection of the household waste.     

Eradication of Salmonella Yoruba in an integrated pig herd

An integrated SPF herd with 320 sows was found infected with Salmonella Yoruba during an annual control among sows, aiming to verify freedom from Salmonella infections. It is believed that the infection was introduced to the herd by purchase of feed. The herd performed an age segregated rearing system. Sows and piglets were reared at a central farm, while growers (25-100 kg body weight) were reared at sub-estates. The growers were free from the infection, and as a consequence a specially designed eradication program was designed. Farrowing and weaning were defined as periods of risk for sows and piglets, respectively. Consequently sows were isolated and individually tested for presence of Salmonella one week before and one week after farrowing. The offspring were tested one week post weaning. To verify freedom from disease among piglets they were also tested another time before transfer to the uninfected sub-estates. Piglets with undefined status regarding Salmonella were denoted animals at risk and not transferred to the sub-estates. Instead they were transferred to a third estate, rented to house pigs at risk. The program was successful. It allowed full production during performance, and the herd was declared free from S. Yoruba seven and a half months after the initial diagnosis.