Alpha- and Gammaproteobacterial Methanotrophs Codominate the Active Methane-Oxidizing Communities in an Acidic Boreal Peat Bog

The objective of this study was to characterize metabolically active, aerobic methanotrophs in an ombrotrophic peatland in the Marcell Experimental Forest, Minnesota, USA. Methanotrophs were investigated in the field and in laboratory incubations using DNA-stable isotope probing, expression studies on particulate methane monooxygenase (pmoA) genes, and amplicon sequencing of 16S rRNA genes. Potential rates of oxidation ranged from 14-17 μmol CH4 g dry wt soil-1 d-1. Within DNA-SIP incubations, the relative abundance of methanotrophs increased from 4% in situ to 25-36% after 8 -14 days. Phylogenetic analysis of the 13C-enriched DNA fractions revealed the active methanotrophs were dominated by the genera Methylocystis (Type II; Alphaproteobacteria), Methylomonas, and Methylovulum (Type I; Gammaproteobacteria). In field samples, a transcript-to-gene ratio of 1 to 2 was observed for pmoA in surface peat layers which attenuated rapidly with depth, indicating the highest methane consumption was associated with the 0-10 cm depth interval. Metagenomes and sequencing of cDNA pmoA amplicons from field samples confirmed the dominant active methanotrophs were Methylocystis and Methylomonas. Although Type II methanotrophs have long been shown to mediate methane consumption in peatlands, our results indicate members of the genera Methylomonas and Methylovulum (Type I) can significantly contribute to aerobic methane oxidation in these ecosystems

Media 2: Four-dimensional key design in amplitude, phase, polarization and distance for optical encryption based on polarization digital holography and QR code

Originally published in Optics Express on 25 August 2014 (oe-22-17-20727

Media 1: Four-dimensional key design in amplitude, phase, polarization and distance for optical encryption based on polarization digital holography and QR code

Originally published in Optics Express on 25 August 2014 (oe-22-17-20727

Media 2: Four-dimensional key design in amplitude, phase, polarization and distance for optical encryption based on polarization digital holography and QR code

Originally published in Optics Express on 25 August 2014 (oe-22-17-20727

A study on the correlation of placental anastomosis and superficial vascular branches of selective fetal growth restriction in monochorionic diamniotic twins

Abstract Introduction The main purpose of the present study was to investigate the correlation between placental anastomosis and superficial vascular branches in selective fetal growth restriction (sFGR) in monochorionic diamniotic twins. Materials and methods This was a retrospective analysis of the pregnancy data and placental perfusion of 395 patients with monochorionic diamniotic (MCDA) twin pregnancies delivered at our hospital from April 2013 to April 2020. We divided the patients into two groups and compared the number of placental superficial vascular branches in sFGR twins and normal MCDA twins. The correlation between the placental anastomosis and the number of superficial vascular branches in sFGR and normal MCDA twins was also investigated. Results The number of umbilical arterial branches and umbilical venous branches was less than larger twins in sFGR, larger twins in normal MCDA and smaller twins in normal MCDA. (11.83 [4–44], 21.82 [7–50], 19.72 [3–38], 14.85 [0–31], p < 0.001, 6.08 [1–18], 9.60 [3–22], 9.96 [2–22], 8.38 [1–20], p < 0.00) For smaller twins in the sFGR group, the number of umbilical venous branches was positively associated with AA anastomosis overall diameter, AV anastomosis overall diameter and all anastomosis overall diameter. (r = 0.194, 0.182 and 0.211, p < 0.05) Conclusions The risk of sFGR may arise when the placenta from MCDA twins shows a poor branching condition of placental superficial vessels. For the smaller twin of sFGR, regular ultrasound examination of the number of the umbilical venous branches may help to predict artery-to-artery (AA) overall diameter, artery‐to‐vein (AV) overall diameter and all anastomosis overall diameter

The biogeochemistry of the suboxic and anoxic zones in the cariaco basin Biogeoquímica de las zonas subóxica y anóxica en la fosa de cariaco

A decade-long study of the Cariaco Basin has demonstrated that the suboxic interface in this system is temporally and spatially variable and that it is the home for a diverse and active microbial community. The thickness and structure of the suboxic zone appears to be primarily controlled by the physics of the basin, with oxygen containing intrusions occurring from both eastern and western sills. The microbial populations, which include both heterotrophic and chemoautotrophic micro-organisms, are actively growing at rates which cannot be supported by vertical transport of oxidants or reductants. Our studies suggest that the microbial loop depends on cycling of intermediate oxidation state sulfur species (sulfite, thiosulfate and elemental S) possibly coupled with cycling of metal oxides. Production of these species is maintained by the active intrusion process and by transport from land of iron and metal oxides during rain events.<br>Los estudios realizados en la Fosa de Cariaco durante una década han demostrado que la interfaz sub-óxica en este sistema posee una variabilidad temporal y espacial, siendo el hábitat de una comunidad microbiana diversa y activa. La circulación en la cuenca, caracterizada por intrusiones ricas en oxígeno desde los umbrales oriental y occidental, controla aparentemente el espesor y la estructura de la zona sub-óxica. Las poblaciones microbianas, las cuales incluyen microorganismos heterotróficos y quimioautotróficos, crecen activamente a un ritmo que no es posible que se sostenga mediante el transporte vertical de oxidantes y reductores. La presente investigación sugiere que el anillo microbiano depende de la utilización de especies del azufre con estados de oxidación intermedio (sulfito, tiosulfato y S elemental) acoplada posiblemente con el ciclo de los óxidos metálicos. La producción de estas especies se mantiene por procesos activos de intrusión y por el transporte desde el continente de hierro y óxidos metálicos durante los episodios lluviosos

Spatial and temporal variations of Synechococcus and picoeukaryotes in the Taiwan Strait, China

The size-fractionated phytoplankton biomass, and the spatial and temporal variations in abundance of Synechococcus (SYN) and picoeukaryotes (PEUK) were measured in the Taiwan Strait during three cruises (August 1997, February-March 1998, and August 1998). The results show that picophytoplankton and nanophytoplankton dominate the phytoplankton biomass, in average of 38% and 40%, respectively. SYN and PEUK varied over time in abundance and carbon biomass, greater in summer than in winter, in range of (7.70-209.2) x 10(6) and (0.75-15.4) x 10(6) cells/cm(2) in the abundance, and 1.93-52.3 and 1.57-32.4 mu gC/cm(2) in the carbon biomass, for SYN and PEUK, respectively. The horizontal distributions of both groups were diurnal but heterogeneous in abundance, depending on the groups and layer of depths. Temperature is the key controlling factor for picophytoplankton distribution (especially in winter) in the Strait