Identification of Crassostrea ariakensis and related oysters by multiplex species-specific PCR

Genetic markers are needed for rapid and reliable identification of oysters. In this study, we developed multiplex genus- and species-specific PCR markers for the identification of oysters from China. We used the mitochondrial cytochrome oxidase I (COI) and nuclear 28S ribosomal RNA genes for marker development. DNA sequences from different species were obtained from GenBank or by direct sequencing. Sequences were aligned, and genus- and species-specific nucleotides were identified. Primers were designed for genus/species-specific amplification to generate fragments of different sizes. A multiplex set of genus- and species-specific primers from the 28S gene was able to separate C. ariakensis and C. hongkongensis from other species and assign oysters to four genera. A set of species-specific COI primers provided positive identification of all five Crassostrea species from China, C. ariakensis, C. hongkongensis, C. angulata, C. gigas, and C. sikamea in a single PCR. The multiplex PCR assays do not require fluorescence-labeling or post-PCR enzyme digestion, providing a simple, fast and reliable method for the identification of oysters from China.

Selective and specific detection of sulfate-reducing bacteria using potentiometric stripping analysis

A fast, sensitive and reliable potentiometric stripping analysis (PSA) is described for the selective detection of the marine pathogenic sulfate-reducing bacterium (SRB). Desulforibrio caledoiensis. The chemical and electrochemical parameters that exert influence on the deposition and stripping of lead ion, such as deposition potential, deposition time and pH value were carefully studied. The concentration of SRB was determined in acetate buffer solution (pH 5.2) under the optimized condition (deposition potential of -1.3 V. deposition time of 250 s, ionic strength of 0.2 mol L-1 and oxidant mercury (II) concentration of 40 mg L-1). A linear relationship between the stripping response and the logarithm of the bacterial concentration was observed in the range of 2.3 x 10 to 2.3 x 10(7) cfu mL(-1). In addition, the potentiometric stripping technique gave a distinct response to the SRB, but had no obvious response to Escherichia coli. The measurement system has a potential for further applications and provides a facile and sample method for detection of pathogenic bacteria. (C) 2010 Elsevier B.V. All rights reserved.

Hypoxia-inducible factor 1 alpha cDNA cloning and its mRNA and protein tissue specific expression in domestic yak (Bos grunniens) from Qinghai-Tibetan plateau

Adaptation to hypoxia is regulated by hypoxia-inducible factor 1 (HIF-1), a heterodimeric transcription factor consisting of an oxygen-regulated a-subunit and a constitutively expressed beta-subunit. How animals living on Qinghai-Tibetan plateau adapt to the extreme hypoxia environment is known indistinctly. In this study, the Qinghai yak which has been living at 3000-5000 m attitude for at least two millions of years was selected as the model of high hypoxia-tolerant adaptation species. The HIF-1 alpha ORFs (open reading frames) encoding for two isoforms of HIF-1 alpha have been cloned from the brain of the domestic yak. Its expression of HIF-1 alpha was analyzed at both mRNA and protein levels in various tissues. Both its HIF-1 alpha mRNA and protein are tissue specific expression. Its HIF-1 alpha protein's high expression in the brain, lung, and kidney showed us that HIF-1 alpha protein may play an important role in the adaptation to hypoxia environment. (c) 2006 Elsevier Inc. All rights reserved.

A molecular marker that is specific to medicinal rhubarb based on chloroplast trnL/trnF sequences

"Da-Huang" (Radix et Rhizoma Rhei, medicinal rhubarb), a famous and important Traditional Chinese Medicine, has often been confused with the adulterant species in the same genus, Rheum. Through sequencing the trnL (UAA)/trnF (GAA) regions of chloroplast DNA of thirteen species of Rheum (three medicinal rhubarb species and ten adulterant ones), a molecular marker of the medicinal species was found. A pair of PCR primers based on the sequences, was thus designed, which amplified a highly specific DNA fragment in medicinal rhubarb exclusively, and absent in the adulterants at all under an optimized PCR condition.

Low temperature specific heat and thermal stability of Fe-B ultrafine amorphous alloy particles

Fe-B ultrafine amorphous alloy particles (UFAAP) were prepared by chemical reduction of Fe3+ with NaBHO4 and confirmed to be ultrafine amorphous particles by transmission electron microscopy and X-ray diffraction. The specific heat of the sample was measured by a high precision adiabatic calorimeter, and a differential scanning calorimeter was used for thermal stability analysis. A topological structure of Fe-B atoms is proposed to explain two crystallization peaks and a melting peak observed at T=600, 868 and 1645 K, respectively.

A new europium chelate-based phosphorescence probe specific for singlet oxygen

The first Eu3+ chelate-based phosphorescence probe specific for singlet oxygen has been designed, synthesized and characterized. The probe is highly sensitive, selective and water soluble for time-resolved luminescence detection of singlet oxygen with a detection limit of 2.8 nM.