The C-C bond cleavage of a lignin model compound, 1,2-diarylpropane-1,3-diol, with a heme-enzyme model catalyst tetraphenylporphyrinatoiron(III)chloride in the presence of tert-butylhydroperoxide

The catalytic C-C bond cleavage of a lignin model compound was investigated by use of tetraphenylporphyrinatoiron(III)chloride as a model for enzymic degradation of lignin. The C-C bond of the lignin model compound 1,2-bis(4-ethoxy-3-methoxyphenyl) propane-1,3-diol was oxidatively cleaved by catalysis of iron-porphyrins in the presence of tert-butylhydroperoxide or iodosylbenzene at a room temperature. The products formed after complete oxidation of the substrate were identified as 4-O-ethylvanillin, alpha-hydroxy-4-ethoxy-3-methoxyacetophenone, 4-O-ethylvanillic acid, 4-ethoxy-3-methoxyphenylglycol, 4-ethoxy-3-methoxy-alpha-(4-ethoxy-3-methoxyphenyl)-beta-hydroxypropi ophenone and formaldehyde.     

Barn swallow (<Emphasis Type="Italic">Hirundo rustica</Emphasis>) parents use past information to decide on food provisioning to the brood,but not to decide on allocation within the brood

The begging behavior of birds is thought to influence the allocation of food within the brood (allocation function) or to increase the total amount of food delivered to the brood (delivery function). Considering the nature of the feeding activity of passerines, in which hundreds of feeding events occur in a single day, parents may not necessarily decide the amount of resources allocated to each nestling/brood during a single feeding event. To examine this possibility, the relationship between begging intensity and parental responses to allocation and delivery functions was tested and modeled at multi-temporal scales in the barn swallow (Hirundo rustica). Comparison of models revealed that barn swallow parents differed in the temporal scales at which they respond to nestlings with respect to these two functions. While barn swallow parents decide which nestling to feed at a focal feeding event according to chick begging of the focal feeding event, they integrated past information on total begging effort to determine delivery rates to their offspring during the 14 and 6 min prior to the focal feeding event in males and females, respectively. These findings highlight that it is important to investigate parental response to begging at appropriate temporal scales when analyzing begging functions.     

Inhalation of Stachybotrys chartarum Evokes Pulmonary Arterial Remodeling in Mice, Attenuated by Rho-Kinase Inhibitor

Stachybotrys chartarum, a ubiquitous fungus in our environment, has been suspected of causing respiratory symptoms in humans, such as acute infant pulmonary hemorrhage and asthma. We previously established a mouse model in which repeated inhalation of Stachybotrys chartarum spores caused pulmonary hypertension. To further investigate the model, particularly in the pulmonary circulation, mice were intra-tracheally injected with spores, 18 times over 12 weeks. Severe muscularization was observed in the small- to medium-sized pulmonary arteries. Bronchoalveolar lavage fluid revealed an increase in eosinophils accompanied by high concentrations of Th2-associated cytokines, IL-4, IL-5, but not Th1-associated IFN-γ. The remodeling was temporary, resolving after cessation of spore inhalation. Chronic inhibition of the RhoA/Rho-kinase pathway by fasudil attenuated pulmonary arterial remodeling. These data suggest that Stachybotrys-mediated remodeling is caused by Th2-associated inflammation and can be resolved by Rho-kinase inhibition, either through direct effects on smooth muscle hypertrophy or through indirect effects on vascular inflammation. These data also show that extensive pulmonary vascular remodeling, often thought of as a fixed lesion, will spontaneously resolve in the absence of underlying molecular etiology.     

Surface carbohydrate analysis and bioethanol production of sugarcane bagasse pretreated with the white rot fungus, Ceriporiopsis subvermispora and microwave hydrothermolysis

Effects of pretreatments with a white rot fungus, Ceriporiopsis subvermispora, and microwave hydrothermolysis of bagasse on enzymatic saccharification and fermentation were evaluated. The best sugar yield, 44.9 g per 100 g of bagasse was obtained by fungal treatments followed by microwave hydrothermolysis at 180 °C for 20 min. Fluorescent-labeled carbohydrate-binding modules which recognize crystalline cellulose (CjCBM3-GFP), non-crystalline cellulose (CjCBM28-GFP) and xylan (CtCBM22-GFP) were applied to characterize the exposed polysaccharides. The microwave pretreatments with and without the fungal cultivation resulted in similar levels of cellulose exposure, but the combined treatment caused more defibration and thinning of the plant tissues. Simultaneous saccharification and fermentation of the pulp fractions obtained by microwave hydrothermolysis with and without fungal treatment, gave ethanol yields of 35.8% and 27.0%, respectively, based on the holocellulose content in the pulp. These results suggest that C. subvermispora pretreatment could be beneficial part of the process to produce ethanol from bagasse.     

A novel heterotetrameric structure of the crenarchaeal PCNA2-PCNA3 complex

Proliferating cell nuclear antigen (PCNA) is a key protein that orchestrates the arrangement of DNA-processing proteins on DNA during DNA metabolism. In crenarchaea, PCNA forms a heterotrimer (PCNA123) consisting of PCNA1, PCNA2, and PCNA3, while in most eukaryotes and many archaea PCNAs form a homotrimer. Interestingly, unique oligomeric PCNAs from Sulfolobus tokodaii were reported in which PCNA2 and PCNA3 form a heterotrimer without PCNA1. In this paper, we describe the crystal structure of the stoPCNA2-stoPCNA3 complex. While most DNA sliding clamps form ring-shaped structures, our crystal structure showed an elliptic ring-like heterotetrameric complex, differing from a previous reports. Furthermore, we investigated the composition and the dimension of the stoPCNA2-stoPCNA3 complex in the solution using gel-filtration column chromatography and small-angle X-ray scattering analyses, respectively. These results indicate that stoPCNA2 and stoPCNA3 form the heterotetramer in solution. Based on our heterotetrameric structure, we propose a possible biological role for the heterotetrameric complex as a Holliday junction clamp.     

Phylogeography and genetic structuring of European nine-spined sticklebacks (Pungitius pungitius)-mitochondrial DNA evidence

As a consequence of colonisation from different glacial refugia, many northern European taxa are split into distinct western and eastern lineages. However, as for the nine-spined stickleback (Pungitius pungitius), the exact location of the contact zone between lineages often remains poorly known. We assessed the genetic differentiation and diversity in the nine-spined stickleback within Europe using 1037 base pairs of cytochrome b sequence for 320 individuals from 57 locations, including pond, lake, river, and coastal habitats. Our main aims were (i) to locate the contact zone between the previously recognized western and eastern lineages, (ii) investigate latitudinal patterns in genetic diversity, (iii) compare genetic diversity among different habitat types, and (iv) date the known split between eastern and western lineages. The data revealed the split between eastern and western to be located across the Danish Straits and roughly following the Norway/Sweden border to the North. Reference sites from Canada form their own clades, and one of the Canadian sites was found to have a haplotype common to the Eastern European lineage, possibly representing an ancestral polymorphism. The split between the two European clades was dated to approximately 1.48 million years ago (Mya), and between Canada and Europe to approximately 1.62 Mya. After controlling for habitat effects, nucleotide (but not haplotype) diversity across populations decreased with increasing latitude. Coastal populations showed significantly higher haplotype diversity (but not nucleotide diversity) than pond populations, but there were no detectable differences in haplotype diversity among different freshwater habitat types (viz. river, lake and pond populations), or between coastal and lake/river populations. Sequences were found to cluster according to their geographic proximity, rather than by habitat type, and all habitat types were found within each major clade, implying that colonisation and adaptation between the coastal and freshwater environments in different regions must have occurred in parallel.