Long-range interactions within a nonnative protein

Protein folding and unfolding are coupled to a range of biological phenomena, from the regulation of cellular activity to the onset of neurodegenerative diseases. Defining the nature of the conformations sampled in nonnative proteins is crucial for understanding the origins of such phenomena. We have used a combination of nuclear magnetic resonance (NMR) spectroscopy and site-directed mutagenesis to study unfolded states of the protein lysozyme. Extensive clusters of hydrophobic structure exist within the wild-type protein even under strongly denaturing conditions. These clusters involve distinct regions of the sequence but are all disrupted by a single point mutation that replaced residue Trp62 with Gly located at the interface of the two major structural domains in the native state. Thus, nativelike structure in the denatured protein is stabilized by the involvement of Trp62 in nonnative and long-range interactions.     

Jahreszeitliche Schwefeldynamik semisubhydrischer Salzmarschen

Seasonal sulfur dynamic of Salic Fluvisols The seasonal sulfur dynamic of semisubmerged Salic Fluvisols was investigated in Neuwarpeler-Außengroden (Southern North Sea coast) from August 1991 to October 1992. The study was mainly performed by investigating different sulfur species: Total sulfur (HNO₃/HCI digestion), sulfide-sulfur (HCI digestion) and sulfate-sulfur were measured, organic sulfur and pyrite-sulfur were calculated. The dominating sulfur fraction was pyrite, followed by organic sulfur, sulfate and sulfide. The sulfide contents did not change remarkably in the course of the year. The sulfate contents were highest in summer and lowest in winter. They were positively correlated with the chloride contents. The total sulfur contents were highest in summer and winter. They show two phases of pyrite formation. The redox potentials show a simultaneous reoxidation in summer.     

Ligninolytic fungi in bioremediation: extracellular enzyme production and degradation rate

Ligninolytic fungi can be used for remediation of pollutants in water and soil. Extracellular peroxidases and laccases have been shown to oxidize recalcitrant compounds in vitro but the likely significance of individual enzyme levels in vivo remains unclear. This study documents the amounts and activities of Mn-dependent peroxidase (MnP), lignin peroxidase and laccase (LAC) in various species of ligninolytic fungi grown in liquid medium and soil and their effect on degradation of polycyclic aromatic hydrocarbons (anthracene and pyrene), a polychlorinated biphenyl mixture (Delor 106) and a number of synthetic dyes. Stationary cultures of a highly degradative strain Irpex lacteus exhibited 380-fold and 2-fold increase in production of MnP and LAC, respectively, compared to submerged cultures. Addition of Tween 80 to the submerged culture increased MnP levels 260-fold. High levels of MnP correlated with efficient decolorization of Reactive Orange 16 azo dye but not of Remazol Brilliant Blue R anthraquinone dye. Degradation of anthracene and pyrene in spiked soil by straw-grown explorative mycelium of Phanerochaete chrysosporium, Trametes versicolor and Pleurotus ostreatus showed the importance of MnP and LAC levels secreted into the soil. The importance of high fungal enzyme levels for efficient degradation of recalcitrant compounds was better demonstrated in liquid media compared to the same strains growing in soil.     

Comparisons of Isozyme Patterns in Resynthesized Amphihaploid Rapeseed (Brassica napus) and Their Parental Species Brassica campestris and Brassica oleracea

Resynthesized rapeseed plants produced by embryo culture and the progeny of their selfed parents from Brassica oleracea and Brassica campestris were analyzed by starch gel electrophoresis staining of enzymes GPI, LAP and SDH. In at least one unequivocal case it could be proved for each enzyme system studied that the alleles of both parents arc independently expressed in the newly synthesized individuals and that in the pattern of the dimeric enzyme GPI interlocus bands of the homoeologous loci arc visible. Comparisons with enzyme patterns in cultivated B. napus leads to the conclusion that in general active enzyme loci of both parental genomes are present. This is of great significance in estimating slide frequencies, degree of heterozygosity and other genetic parameters of B. nupus populations/cultivars.     

Exploring global irrigation patterns: A multilevel modelling approach

Globally, areas that are equipped for irrigation have almost doubled in size over the past 50 years and further expansions are expected for the future, to meet a growing food demand. For developing countries, the Food and Agriculture Organization of the United Nations (FAO) expects these areas to be expanded by 40 million ha, by 2030. Knowledge about the constraints to irrigation and spatially explicit information about the potential for irrigation expansion, however, are lacking on a global scale. The objective of our study was to explain the global pattern of irrigated croplands and to identify cropping regions where irrigation is likely to be expanded. We accounted for biophysical determinants, such as humidity and slope, mainly at grid-cell level. Socio-economic and governance determinants, for example, Gross Domestic Product (GDP) and control of corruption, were primarily considered on a country level, given the limitations in availability of sub-national data and the role of national level governance in irrigation decisions. To identify the variability of the determinants within these two spatial levels, we conducted a multilevel analysis. This is a method employing regression models that explicitly account for hierarchically structured data. Results show significant variability in terms of irrigation. While 56% of the global variance in irrigation occurs between countries, 44% occurs within countries. Our results suggest that it is necessary to consider biophysical, socio-economic and governance information for identifying cropland areas that are likely to be under irrigation. Under current conditions, conversion from rainfed to irrigated cropland is most likely in eastern China, northern Africa, and parts of the Mediterranean region.     

The role of albumin replacement in the critically ill veterinary patient

Objective: To review the human and veterinary literature on the physiological role and effects of therapeutic albumin supplementation. Data sources: Data from human and veterinary literature was reviewed. Human data synthesis: Hypoalbuminemia often occurs in a variety of critical illnesses, and contributes to the development of life‐threatening complications, including pulmonary edema, delayed wound healing, feeding intolerance, hypercoaguability, and multiple organ dysfunction. Serum albumin concentration has been used as a prognostic indicator in cases of chronic hypoalbuminemia. The use of albumin replacement therapy in humans is sometimes controversial, but may be associated with improved morbidity and decreased mortality. Veterinary data synthesis: Unlike human literature, there is a paucity of controlled clinical studies in the literature regarding albumin supplementation in veterinary patients. Rather, the majority of published studies were performed in experimental animals or via retrospective analyses. One recent study evaluated the use of plasma to improve albumin concentration in dogs with hypoalbuminemia. Other older studies investigated wound healing in dogs with experimentally induced hypoalbuminemia. As in human medicine, serum albumin concentration may be helpful as a prognostic indicator in critically ill dogs. Conclusion: Albumin is one of the most important proteins in the body because of its role in maintenance of colloid oncotic pressure, substrate transport, buffering capacity, as a mediator of coagulation and wound healing, and free‐radical scavenging. Albumin replacement in veterinary medicine is difficult, but until prospective clinical trials determine the efficacy of albumin replacement are conducted, a suggested clinical guideline would be to maintain albumin concentration at or above 2.0 g/dl utilizing fresh frozen plasma.     

Susceptibility of sheep to European bat lyssavirus type-1 and -2 infection: a clinical pathogenesis study

European bat lyssaviruses (EBLVs) have been known to cross the species barrier from their native bat host to other terrestrial mammals. In this study, we have confirmed EBLV-1 and EBLV-2 susceptibility in sheep (Ovis ammon) following intracranial and peripheral (intramuscular) inoculation. Notably, mild clinical disease was observed in those exposed to virus via the intramuscular route. Following the intramuscular challenge, 75% of the animals infected with EBLV-1 and 100% of those that were challenged with EBLV-2 developed clinical signs of rabies and then recovered during the 94-day observation period. Disease pathogenesis also varied substantially between the two viruses. Infection with EBLV-1 resulted in peracute clinical signs, which are suggestive of motor neuron involvement. Antibody induction was observed and substantial inflammatrory infiltrate in the brain. In contrast, more antigen was detected in the EBLV-2-infected sheep brains but less inflammatory infiltrate and no virus neutralising antibody was evident. The latter involved a more protracted disease that was behaviour orientated. A high infectious dose was required to establish EBLV infection under experimental conditions (> or =5.0 logs/ml) but the infectious dose in field cases remains unknown. These data confirm that sheep are susceptible to infection with EBLV but that there is variability in pathogenesis including neuroinvasiveness that varies with the route of infection. This study suggests that inter-species animal-to-animal transmission of a bat variant of rabies virus to a terrestrial mammal host may be limited, and may not always result in fatal encephalitis.