DNA barcoding of Antarctic marine zooplankton for species identification and recognition

Polar zooplankton are particularly sensitive to climate change, and have been used as rapid-responders to indicate climate-induced changes in the fragile Antarctic ecosystem. DNA barcoding provides an alternative approach for rapid zooplankton species identification. Ninety-four specimens belonging to 32 Antarctic zooplankton species were barcoded to construct a comprehensive reference library. An 830 to 1 050 base-pair region of the mitochondrial cytochrome c oxidase subunit I (mtCOI) gene was obtained as DNA barcodes. The intraspecific variation of the gene ranged from 0 to 2.6% (p-distance), with an average of 0.67% (SD=0.67%). The distance between species within the same genera ranged from 0.1% (Calanus) to 29.3%, with an average of 15.3% (SD=8.4%). The morphological and genetic similarities between Calanus propinquus and C. simillimus raise new questions about the taxonomic status of C. simillimus. With the exception of the two Calanus species, the intraspecific genetic divergence was much smaller than the interspecific divergence among congeneric species, confirming the existence of a barcode gap for Antarctic zooplankton. In addition, species other than Calanus sp. formed a monophyletic group. Therefore, we have confirmed DNA barcoding as an accurate and efficient approach for zooplankton identification in the Antarctic area (except for Hydromedusa, Tunicata, and other gelatinous zooplankton). Indicator vector analysis further confirmed this conclusion. The new primer sets issued here may facilitate the study of Antarctic marine zooplankton species composition by environmental metagenetic analysis

Mitochondrial genomes of four pelagic Chaetognaths Zonosagitta bedoti, Zonosagitta pulchra, Ferosagitta robusta, and Aidanosagitta regularis and the phylogenetic relationships on Sagittiae

Chaetognaths possess simplified body plan that puzzled their morphological phylogenetic classification. Three complete mitochondrial genomes were determined for Zonosagitta bedoti, Z. pulchra, and Aidanosagitta regularis, and one partial mitochondrial genome was obtained for Ferosagitta robusta. The mitochondrial genomes of the species were small owing to the loss of 23 genes, ranging from 11,604 bp to 12,123 bp. Large-scale rearrangement was also observed in the obtained mitochondrial genomes resembled those of most other Sagittidae species. Our phylogenetic results questioned monophylic status of Zonosagitta because of the inclusion of Ferosagitta and Aidanosagitta in the Zonosagitta clade. Monophyly of Parasagitta and Feerosagitta were supported

The diel vertical migration of zooplankton in the hypoxia area observed by video plankton recorder

1353-1363Temperature, salinity, fluorescence, and dissolved oxygen were investigated together with the vertical distribution of four taxa to discuss the reason for diel vertical migration (DVM). Copepods and chaetognatha performed typical DVM, but only a small part of the population appeared under 40 m. Gelatinous zooplanktons aggregated at the surface water layer shallower than 30 m. DVM of euphausiacea remained uncertain because of the small number of individuals investigated in the study. Our study confirmed that VPR could be used as a valuable tool to study zooplankton DVM. DVM of most zooplankton living in the coastal area of the East China Sea might be affected by multiple environmental elements, such as feeding activities, predator presenting, stratification of water column, and energy utilization

ESDA2004-58565 THE PIV MEASUREMENTS ON THE FLOW FIELDS IN AN UNSHROUDED CENTRIFUGAL PUMP ESDA2004-58565

ABSTRACT PIV was applied to the measurements of flow field in an unshrouded centrifugal pump impeller. Three windows were selected for the measurements .Three operation points of the pump were taken during the measuring. The ratios (Q/QBEP) of the flow rate for measuring are 0.6, 1.0, and 1.4, respectively. The velocity distributions in blade-to-blade passages obtained at different windows give the evidence that the velocity distributions are asymmetric even under the design operation point. A lower velocity zone existed at middle of blade-to-blades passages near the pressure-side of the blade. INTRODUCTION The fluid motion in centrifugal pump is an unsteady motion. The inlet and outlet, the shape of the blade very affect its movement. Under the operation condition including design condition, the flow field may not coincident to the design consumption. The flow field in centrifugal pump impeller is more complicated as compared with other kinds of flow in pipes or valves since the motion of fluids is combined rotational and relative one. In the past decades many efforts were made in measuring the flow fields inside of pumps. However, only a small part of the blade to blade passage was measured due to existing of the suction pipe. On the other hand, the flow fields were measured point by point with a long time so cause the loss of synchronization of the measurements

Flow pattern and hydraulic performance of tubular pump

In order to establish a relationship between flow pattern and hydraulic performance of a tubular pump, the flow pattern and hydraulic performance at a low flow rate, best efficiency point and a high flow rate were investigated by means of flow simulation, performance test and PIV measurement in a tubular pump. The steady flow field in the pump was obtained through solving the time-averaged N-S equations in the multiple reference frames (MRF) with the help of the SIMPLEC algorithm and the RNG k-ε turbulence model. The flow patterns in the pump were analyzed at different operating points. There was a large recirculation zone before the blades inlet when the pump operated at the low flow rate. The flow patterns were fine and there was no any reverse flow regions in the pump when it worked at the BEP (Best Efficiency Point) and the high flow rate. The results indicated the hydraulic loss in the suction pipe is similar to that in a normal pipe, but the hydraulic loss in the discharge pipe depended on operating points. A minimum hydraulic loss in the discharge appeared at the BEP. The estimated performance was in agreement with the test data, both the predicted flow patterns and the PIV measurements showed that there was remarked reverse flow region in front of blades near the tip and there existed a large separated flow zone near the hub downstream of blades at the low flow rate. Thus, attention should be paid on the flow pattern in impeller and guide vanes at a low flow rate in the optimal design of such a tubular pump

Rational Engineering of Bioinspired Anthocyanidin Fluorophores with Excellent Two-Photon Properties for Sensing and Imaging

Fluorescent materials are widely employed in biological analysis owing to their biorthogonal chemistries for imaging and sensing purposes. However, it is always a challenge to design fluorophores with desired photophysical and biological properties, due to their complicated molecular and optical nature. Inspired by anthocyanidin, a class of flower pigments, we designed a new fluorescent molecular framework, AC-Fluor. The new fluorescent materials can be rationally engineered to produce a broad range of fluorescent scaffolds with flexibly tunable emission spectra covering the whole visible light range, from 467 to 707 nm. Furthermore, they exhibit unprecedented environment-insensitive two-photon properties with a substantial cross section as large as 1100 GM in aqueous solution. AC-Fluors demonstrate their biological values through two-photon deep tissue imaging, with penetration depths as much as 300 μm, while exhibiting minimal cytotoxicity. These features engender a rational engineering strategy for the design and optimization of new fluorescent materials for biological imaging

Using arterial–venous analysis to characterize cancer metabolic consumption in patients

Cellular metabolism is altered in many cancer types and the advent of metabolomics has allowed us to understand more about how this is dysregulated. Here, the authors report a method named CARVE to analyse the arterial supply and venous drainage of glioma patients during surgery and identify the metabolites that may be consumed and produced by the cancer