[Microelements in potato and lily samples studied by laser-induced breakdown spectroscopy technology].

A LIBS setup was built in the Institute of Modern Physics. In our experiments, LIBS spectra produced by infrared radiation of Nd:YAG nanosecond laser with 100 and 150 mJ pulse energy, respectively, were measured by fiber optic spectrometer in the ranges of 230-430 nm and 430-1 080 nm with a delay time of 1.7 and gate width of 2 ms for potato and lily samples prepared by vacuum freeze-dried technique. The lines from different metal elements such as K, Ca, Na, Mg, Fe, Al, Mn and Ti, and nonmetal elements such as C, N, O and H, and some molecular spectra from C2, CaO, and CN were identified according to their wavelengths. The relative content of the six microelements, Ca, Na, K, Fe, Al, and Mg in the samples were analyzed according to their representative line intensities. By comparison we found that there are higher relative content of Ca and Na in lily samples and higher relative content of Mg in potato samples. The experimental results showed that LIBS technique is a fast and effective means for measuring and comparing the contents of microelements in plant samples.

Phylogenetic relationships between Tuber pseudoexcavatum, a Chinese truffle, and other Tuber species based on parsimony and distance analysis of four different gene sequences.

Phylogenetic relationships between Tuber pseudoexcavatum and other Tuber species were investigated by studying the sequences of four genes: 5.8S-ITS2, beta-tubulin, protein kinase C and elongation factor 1alpha. The four phylogenetic trees allowed to differentiate the black truffle clade, composed of two subclades, one comprising the Asian black truffles (T. indicum, T. sinense, T. himalayense) and the Perigord black truffle (T. melanosporum), the second comprising T. pseudoexcavatum and T. brumale. These two subclades diverged relatively early. We propose a common ancestor, located between Europe and China, to all the black truffles. The T. brumale/pseudoexcavatum subclade would have started to diverge and migrate first, T. brumale towards Europe through a northern route and T. pseudoexcavatum towards China. Later the T. melanosporum subclade would have started to migrate through the same route, T. melanosporum towards Europe and T. indicum towards China, leading to vicariant species.

[Alteration of PTEN gene expression affects the migration of human airway smooth muscle cells in vitro].

OBJECTIVE: To investigate the changes in human airway smooth muscle cell (HASMC) migration and related signaling pathway after interference with PTEN gene expression. METHOD: HASMCs were infected with an adenovirus vector and RNA interference vector of human PTEN gene to establish the cell model with PTEN gene over-expression (Ad-GFP-PTEN-HASMC) and one with PTEN gene silencing (Ad-shPTEN-HASMC), using Ad-GFP-infected and a blank cells as the negative controls and LY294002 as the positive control. Fluorescence microscopy and flow cytometric analysis were used to evaluate the transfection efficiency, and Western blotting was performed to examine the expression of PTEN and the activation of AKT and ERK1/2 signal pathway. Transwell assay and wound healing assay were used to assess the migration of HASMCs. RESULTS: The adenovirus over-expression vector and RNA interference vector significantly affected the expression of human PTEN gene. Up-regulation of PTEN gene resulted in a slow-down of the HASMC migration, an inhibition of PI3K/AKT signal pathway at the protein level but no changes in Ras-Raf-MEK1/2-ERK1/2 signal pathway. Down-regulated PTEN gene expression, however, was not associated with an enhancement of HASMC migration, but activated PI3K/AKT signal pathway and inhibited Ras-Raf-MEK1/2-ERK1/2 signal pathway. CONCLUSION: Upregulation of PTEN gene can effectively inhibit airway smooth muscle cell migration, the effect of which is probably mediated by the PI3K/AKT pathway.

[Effect of recombinant adenovirus carrying PTEN gene on the proliferation of human airway smooth muscle cells in vitro and the mechanisms].

OBJECTIVE: To observe the effect of exogenous phophatase and tensin homolog deleted on chromosone 10 (PTEN) gene transfer via recombinant adenoviruses on the proliferation of human airway smooth muscle cells (HASMCs) in vitro and investigate the possible mechanisms. METHODS: With a recombinant adenovirus vector containing PTEN (Ad-PTEN) constructed using the pAdxsi system, PTEN gene was transiently transfected into HASMCs and the transfection efficiency was determined by fluorescence microscope. RT-PCR and Western blotting were performed to detect the expression of PTEN mRNA and protein in the infected cells. MTS/PMS assay was used to analyze the proliferation of HASMCs, and the cell cycle changes of the transfected cells were evaluated by flow cytometry with PI staining. The expression levels of Akt and p-A kt proteins were detected by Western blotting, and P21 mRNA expression determined by RT-PCR. RESULTS: The recombinant adenovirus Ad-PTEN showed a wild-type PTEN gene transfer efficiency of 98% at the multiplicity of infection (MOI) of 100. RT-PCR and Western blotting showed that infection with the recombinant adenovirus resulted in PTEN overexpression in the HASMCs, causing also increased ratio of G(0)/G(1) cells and proliferation inhibition of the ASMCs. The overexpression of PTEN significantly decreased the expression level of p-Akt but increased P21 mRNA expression. CONCLUSION: The recombinant adenovirus containing PTEN can be successfully transfected into HASMCs cultured in vitro, resulting in PTEN overexpression at both the mRNA and protein levels. PTEN overexpression can efficiently inhibit the proliferation of HASMCs possibly through the PI3K/PKB/AKt and P21 pathways.

Phylogenetic and populational study of the Tuber indicum complex.

When examined using SEM, Chinese samples of Tuber indicum and T. sinense displayed the same ascospore ornamentation as that of T. pseudohimalayense, T. indicum, collected in India by Duthie in 1899, and samples renamed T. himalayense in 1988. The different authors who named the four taxa (T. indicum, T. himalayense, T. sinense, T. pseudohimalyense) described differences in the surface of the peridium which could be considered as usual variations within a single species. We consider T. indicum, T. himalayense, T. sinense and T. pseudohimalayense as one species, T. indicum. Within this T. indicum complex, according to ITS and beta-tubulin sequences, there are two groups in China, which could be considered as geographical ecotypes. This study is the first to identify a genetic and phylogeographical structure within the Chinese Tuber species.