Carbon assimilating fungi from surface ocean to subseafloor revealed by coupled phylogenetic and stable isotope analysis

Fungi are ubiquitous in the ocean and hypothesized to be important members of marine ecosystems, but their roles in the marine carbon cycle are poorly understood. Here, we use 13C DNA stable isotope probing coupled with phylogenetic analyses to investigate carbon assimilation within diverse communities of planktonic and benthic fungi in the Benguela Upwelling System (Namibia). Across the redox stratified water column and in the underlying sediments, assimilation of 13C-labeled carbon from diatom extracellular polymeric substances (13C-dEPS) by fungi correlated with the expression of fungal genes encoding carbohydrate-active enzymes. Phylogenetic analysis of genes from 13C-labeled metagenomes revealed saprotrophic lineages related to the facultative yeast Malassezia were the main fungal foragers of pelagic dEPS. In contrast, fungi living in the underlying sulfidic sediments assimilated more 13C-labeled carbon from chemosynthetic bacteria compared to dEPS. This coincided with a unique seafloor fungal community and dissolved organic matter composition compared to the water column, and a 100-fold increased fungal abundance within the subseafloor sulfide-nitrate transition zone. The subseafloor fungi feeding on 13C-labeled chemolithoautotrophs under anoxic conditions were affiliated with Chytridiomycota and Mucoromycota that encode cellulolytic and proteolytic enzymes, revealing polysaccharide and protein-degrading fungi that can anaerobically decompose chemosynthetic necromass. These subseafloor fungi, therefore, appear to be specialized in organic matter that is produced in the sediments. Our findings reveal that the phylogenetic diversity of fungi across redox stratified marine ecosystems translates into functionally relevant mechanisms helping to structure carbon flow from primary producers in marine microbiomes from the surface ocean to the subseafloor

Optical properties of rabbit brain in the red and near-infrared: changes observed under in vivo, postmortem, frozen, and formalin-fixated conditions

The outcome of light-based therapeutic approaches depends on light propagation in biological tissues, which is governed by their optical properties. The objective of this study was to quantify optical properties of brain tissue in vivo and postmortem and assess changes due to tissue handling postmortem. The study was carried out on eight female New Zealand white rabbits. The local fluence rate was measured in the VIS/NIR range in the brain in vivo, just postmortem, and after six weeks' storage of the head at -20 degrees C or in 10% formaldehyde solution. Only minimal changes in the effective attenuation coefficient mu(eff) were observed for two methods of sacrifice, exsanguination or injection of KCl. Under all tissue conditions, mu(eff) decreased with increasing wavelengths. After long-term storage for six weeks at -20 degrees C, mu(eff) decreased, on average, by 15 to 25% at all wavelengths, while it increased by 5 to 15% at all wavelengths after storage in formaldehyde. We demonstrated that mu(eff) was not very sensitive to the method of animal sacrifice, that tissue freezing significantly altered tissue optical properties, and that formalin fixation might affect the tissue's optical properties. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)

Intestinal/Multivisceral Transplantation

Intestinal/multivisceral transplantation has evolved from an experimental procedure to the treatment of choice for patients with irreversible intestinal failure and serious complications related to long-term parenteral nutrition. Children who are likely to suffer permanent intestinal failure and benefit from intestinal transplantation include those with a remaining small bowel length of less than 30–40 cm, absence of the ileocecal valve, colonic resection and malabsorptive syndromes. Indications for transplant include frequent severe bouts of catheter associated sepsis, threatened loss of vascular access and the development of liver cirrhosis from cholestasis. Children who are more likely to experience cholestasis from total parenteral nutrition include those who experience persistent hyperbilirubinemia (greater than 6 mg/dl despite enteral nutrition), those with recurrent sepsis and/or bacterial overgrowth and those with minimal tolerance of any enteral feeds in the first few months post resection. The 1 year survival rate after intestinal transplantation has markedly improved over the last several years but long term survival rates have remained unchanged. The improved short term survival rates have led to an increased prevalence of this patient population in intensive care units. Management of intestinal and multivisceral transplant recipients is uniquely challenging because of complications arising from the high incidence of transplant rejection and its treatment. In the ICU, the complexity of medical care for the transplant recipient requires a multidisciplinary approach with coordination by an intensivist in collaboration with the transplant surgeon, gastroenterologist, and other specialists