Establishment of a TaqMan probe-based qPCR assay for detecting microsporidia Enterospora epinepheli in grouper.

Enterospora epinepheli is an intranuclear microsporidian parasite causing serious emaciative disease in hatchery-bred juvenile groupers (Epinephelus spp.). Rapid and sensitive detection is urgently needed as its chronic infection tends to cause emaciation as well as white faeces syndrome and results in fry mortality. This study established a TaqMan probe-based real-time quantitative PCR assays targeting the small subunit rRNA (SSU) gene of E. epinepheli. The relationship between the standard curve of cycle threshold (Ct) and the logarithmic starting quantity (SQ) was determined as Ct = -3.177 lg (SQ) + 38.397. The correlation coefficient (R2 ) was 0.999, and the amplification efficiency was 106.4%. The detection limit of the TaqMan probe-based qPCR assay was 1.0 × 101 copies/µL and that is 100 times sensitive than the traditional PCR method. There is no cross-reaction with other aquatic microsporidia such as Ecytonucleospora hepatopenaei, Nucleospora hippocampi, Potaspora sp., Ameson portunus. The intra-assay and inter-assay showed great repeatability and reproducibility. In addition, the test of clinical samples showed that this assay effectively detected E. epinepheli in the grouper's intestine tissue. The established TaqMan qPCR assays will be a valuable diagnostic tool for the epidemiological investigation as well as prevention and control of E. epinepheli.

Characterization of a GH10 extremely thermophilic xylanase from the metagenome of hot spring for prebiotic production.

A xylanase gene (named xyngmqa) was identified from the metagenomic data of the Gumingquan hot spring (92.5 °C, pH 9.2) in Tengchong City, Yunnan Province, southwest China. It showed the highest amino acid sequence identity (82.70%) to endo-1,4-beta-xylanase from Thermotoga caldifontis. A constitutive expression plasmid (denominated pSHY211) and double-layer plate (DLP) method were constructed for cloning, expression, and identification of the XynGMQA gene. The XynGMQA gene was synthesized and successfully expressed in Escherichia coli DH5α. XynGMQA exhibited optimal activity at 90 °C and pH 4.6, being thermostable by maintaining 100% of its activity after 2 h incubated at 80 °C. Interestingly, its enzyme activity was enhanced by high temperatures (70 and 80 °C) and low pH (3.0-6.0). About 150% enzyme activity was detected after incubation at 70 °C for 20 to 60 min or 80 °C for 10 to 40 min, and more than 140% enzyme activity after incubation at pH 3.0 to 6.0 for 12 h. Hydrolytic products of beechwood xylan with XynGMQA were xylooligosaccharides, including xylobiose (X2), xylotriose (X3), and xylotetraose (X4). These properties suggest that XynGMQA as an extremely thermophilic xylanase, may be exploited for biofuel and prebiotic production from lignocellulosic biomass.

[The Concentration Effect of Near-Infrared Quantum Cutting Luminescence of Tm(3+) Ion Sensitized with Bi(3+) Ion in YNbO(4) Phosphor].

Searching for new energy source is one of the most important projects faced by the global, while the most ideal new energy source is solar cell. Near infrared quantum cutting luminescence method can doubly transfer large energy photon which is not sensitive to Si or Ge solar cell to small energy photon which is sensitive to Si or Ge solar cell. It can resolve the spectral mismatch problem and largely enhance solar cell efficiency. Therefore, it is significant. The concentration effect of near-infrared quantum cutting luminescence of Tm3+Bi3+∶YNbO4 phosphor is reported in present manuscript. Through the measurement of excitation and emission spectra, it is found that the Tm0.058Bi0.010Y0.932NbO4 powder phosphor has intense 1 820.0 nm near-infrared quantum cutting luminescence. Further analysis finds they are multi-photon quantum cutting luminescence induced by the cross-energy transfer process. The population of 1G4 energy level may be directly transferred to lower energy level mainly through {1G4­3H4, 3H6­3H5} and {1G4­3H5, 3H6­3H4} cross-energy transfer processes, i. e. one population of the 1G4 energy level may effectively lead to two populations, which are positioned at the 3H4 and 3H5 energy levels, respectively, mainly through {1G4­3H4, 3H6­3H5} and {1G4­3H5, 3H6­3H4} cross-energy transfer processes. This may also effectively lead to three populations of the 3F4 energy level through {3H4­3F4, 3H6­3F4} cross-energy transfer process from the 3H4 level and multi-phonon non-radiative relaxation from the 3H5 level, respectively. This results in the effective three-photon near-infrared quantum cutting of the 3F4­3H6 fluorescence of Tm3+ ion. It's also found that the sensitization action of Bi3+ ion to Tm3+ ion is very strong. The enhancement of the 1 820.0 nm near-infrared quantum cutting luminescence, of Tm0.058Bi0.010Y0.932NbO4 relative to Tm0.005Y0.995NbO4, is about 175.5 times, when excited by the 302.0 nm light. The present results are significant for the exploration of the next-generation multi-photon near-infrared quantum cutting germanium solar cell.

New boron nitride whiskers: showing strong ultraviolet and visible light luminescence.

Boron nitride whiskers with a special structure have been synthesized by a thermal reaction process. The as-prepared BN whiskers have a length of tens of micrometers and a mean diameter of 500 nm. High-resolution TEM analysis shows that the as-prepared BN whiskers can be described as a nanofiber-interweaved network. Infrared and electron energy loss spectra reveal that the BN whiskers are composed of both sigma-sp2 and sigma-sp3 chemical bonds. The UV-vis absorption spectrum displays the energy band gap of the BN whiskers and multiple fine absorption peaks of the phonon-electron coupling. Both photoluminescence (PL) and cathodoluminescence (CL) measurements show the specially structured BN emits strong UV and visible luminescences, which is a promising material for deep-blue and UV applications.