The synergism of Actinobacillus pleuropneumoniae and influenza A virus in experimentally-infected mice

Models for infecting mice with Influenza A-Virus (A/PR 8/34, H0N1) and Actinobacillus pleuropneumoniae (serotype 9) were developed in Han: NMRI-mice. After infecting mice with sublethal doses of one of the infectious agents, or both together as a mixed infection, animals were subsequently exsanguinated and the lungs washed by bronchoalveolar lavage. Clinical symptoms were recorded daily, examination of lung lavage fluid and sera as well as histology of the lungs were done. An increase in mortality, weight reduction and total cell yield of lung lavage fluid was observed after mixed infection. Compared to mixed infections total protein content and elastase in sera and lung lavage fluid after singular ones were raised not as much. In lung lavage fluid the total cell yield was increased more marked. These alterations indicate a synergistic effect of viruses and bacteria, developed by mixed infection as well as a bacterial infection on top of a viral one. Histopathologically the lung alterations were found to depend on the infectious agent and the mode of infection.     

Virucidal effects of various agents—including protease—against koi herpesvirus and viral haemorrhagic septicaemia virus

In a search for alternative, environmentally friendly and effective disinfecting agents, a commercially available protease—Neutrase^®—was tested in this work for inactivation of koi herpesvirus (KHV) and of viral haemorrhagic septicaemia virus (VHSV). For comparison, the stability of these viral pathogens in similar configurations at various pH values and concentrations of peracetic acid or quicklime, typically used for disinfection, was tested. Therefore, virus suspensions were incubated with various concentrations of different agents for 24 hr and the titre of the remaining infectious particles was determined by virus titration. Furthermore, the treatment of both viruses, with the agents at concentrations that were previously appointed as effective, was also examined in the presence of solid material (quartz sand). All procedures investigated in this study, including the protease treatment, were able to reduce the titre of KHV and VHSV below the detection limit of the titration. Although further studies are necessary, this is the first report of the application of a protease for the inactivation of the selected fish pathogens, demonstrating the great potential of the latter for disinfection.     

Climate-forced variability of ocean hypoxia

Oxygen (O(2)) is a critical constraint on marine ecosystems. As oceanic O(2) falls to hypoxic concentrations, habitability for aerobic organisms decreases rapidly. We show that the spatial extent of hypoxia is highly sensitive to small changes in the ocean's O(2) content, with maximum responses at suboxic concentrations where anaerobic metabolisms predominate. In model-based reconstructions of historical oxygen changes, the world's largest suboxic zone, in the Pacific Ocean, varies in size by a factor of 2. This is attributable to climate-driven changes in the depth of the tropical and subtropical thermocline that have multiplicative effects on respiration rates in low-O(2) water. The same mechanism yields even larger fluctuations in the rate of nitrogen removal by denitrification, creating a link between decadal climate oscillations and the nutrient limitation of marine photosynthesis.     

The measure mix matters: multiple-component plant protection is indispensable for coping with the enormous genome plasticity and mutation rates in pathogenic microorganisms

Efficient plant protection is of fundamental importance in order to warrant food security. Here, we present arguments that a coordinate approach in plant protection is urgently required, taking advantage of a broad mix of measures, including modern synthetic chemistries, capable of protecting plants from adverse organisms.