Daxu Li

Anticancer activity and quantitative analysis of flavone of Cirsium japonicum DC

Cirsium japonicum DC, a traditional Chinese medicine, has been widely used as an antihemorrhagic and diuretic agent. The objective of this study was to perform quantitative analysis of flavone by reversed-phase HPLC and examine the anticancer activity of C. japonicum DC in the S180 and H22 mice. Cirsium japonicum DC was separated and purified with several chromatography techniques and two flavone compounds, pectolinarin and 5,7-dihydroxy-6,4′-dimethoxyflavone, were isolated. The content of these two compounds in the methanol, ethanol, and aqueous extractions respectively was determined by HPLC as follows: pectolinarin 1.87%, 1.65%, 1.27%; 5,7-dihydroxy-6,4′-dimethoxyflavone: 0.515%, 0.42%, 0.221%. Furthermore, the effect of the two flavones on the anticancer activity in S180 and H22 mice was studied. Our research shows that these two flavones greatly inhibit cancer cell growth. The rate of inhibiting S180 mice was 55.77% at 50 mg kg - 1, and the rate of life lengthening was 99.13% at 50 mg kg - 1 in H22 mice.

A novel genotypic test for rapid detection of multidrug-resistant Mycobacterium tuberculosis isolates by a multiplex probe array

Aims:  To develop and evaluate a novel genotypic test for rapid detection of rifampicin and isoniazid resistance of multidrug‐resistant (MDR) Mycobacterium tuberculosis isolates by a multiplex probe array.

Genetic Diversity of Nine Populations of the Black Goat (Capra hircus) in Sichuan, PR China

Abstract Sixteen polymorphic primers screened from 100 random primers were selected to analyze the randomly amplified polymorphic DNA (RAPD) of 540 domesticated black goats (Capra hircas) from 9 different geographical populations in Sichuan Province of China. After the test, 170 entirely repeatable RAPD markers representing goat polymorphisms were obtained from the 16 polymorphic primers, the lengths of the markers ranging from 0.1 to 2.5 kb. The genetic distance among the black goat populations ranges from 0.1051 to 0.2978. The similarity coefficient (0.9002) between Jintang and Lezhi black goats was the highest in the 9 populations, followed by the coefficient (0.8953) between Jialing and Yinshan goats, while that between Jiangan and Huili goats was found to be the lowest (0.7424). The coefficient of differentiation among population genes (Gst) was 0.2766, indicating a comparatively low degree of differentiation among the black goat populations. A UPGMA dendrogram constructed from similarity coefficients showed that the two populations from Huili and Baiyu, which are found mostly on the Western Sichuan plateau and in mountainous areas, clustered together, and the other seven populations formed another group. It can also be clearly seen that the Huili and Baiyu populations are very special, and must have been closely related in the past, even though their link with the other populations is quite weak as a result of genetic communication. The results of the experiment offer some crucial scientific data useful for the breeding of black goats.

Genotypic Analysis of Multidrug-Resistant Mycobacterium tuberculosis Isolates Recovered From Central China

DNA sequencing analysis was used to investigate genetic alterations in the rpoB, katG, and inhA regulatory region and embB in 66 Mycobacterium tuberculosis isolates recovered from Central China. Of the 36 multidrug-resistant isolates, 33 (92%) had mutations in the amplified region of rpoB. The most frequent mutation (58%, 19/36) was S531L (TCG→TTG). At least one mutation was found in the katG and inhA regulatory region in 83% (30/36) of the multidrug-resistant isolates, and mutations at katG codon 315 were identified in 78% (28/36). Alterations at embB306 may not confer resistance to EMB, and embB306 mutants were more frequently accompanied by rpoB mutations (100%, 16/16) than by katG 315 mutations (75%, 12/16). Our results show that geographic variation in the molecular genetic mechanism is responsible for drug resistance in multidrug-resistant M. tuberculosis. This observation will facilitate the development of a rapid molecular drug resistance screening approach for drug-resistant M. tuberculosis.

Molecular insights of genetic variation in Erianthus arundinaceus populations native to China.

Background E. arundinaceus (Retz.) Jeswiet is a warm-season, tall-growing perennial species native to much southern portion in China. The grass has been extensively used in sugarcane breeding and is recently targeted as a bioenergy feedstock crop. However, information on the genetic structure of the Chinese wild germplasm is limited. Knowledge of genetic variation within and among populations is essential for breeding new cultivars in the species. The major objective of this study was to quantify the magnitude of genetic variation among and within natural populations in China. Methodology/Principal Findings In this experiment, we analyzed genetic variation of 164 individuals of 18 populations collected from natural habitats in six Chinese provinces using 20 sequence-related amplified polymorphism (SRAP) primer pairs generating 277 polymorphic bands. Among and within the populations, the percentage of polymorphic bands (PPB) was 80.00% and 27.07%, genetic diversity (HE) was 0.245 and 0.099, effective number of alleles (NE) was 1.350 and 1.170, and Shannons information index (I) was 0.340 and 0.147, respectively. The populations were clustered into six groups exhibiting a high level of genetic differentiation, which was highly associated with geographic origins of respective germplasm populations, but was not significantly associated with geographic distances between the populations. Conclusions/Significance This is the first report indicating that large genetic variation exists in the Chinese E. arundinaceus germplasm based on the SRAP molecular marker analysis of native populations. The genetic structure of populations in the species has been substantially affected by geographic landforms and environments. The diverse collection will be highly valuable in genetic improvement in the species per se and likely in sugarcane.

Modal wavefront reconstruction from slope measurements for rectangular apertures.

We present a modal wavefront reconstruction from slope measurements for rectangular optical components of high-power laser systems. Wavefront reconstruction with slope data is an important approach used for wavefront control or correction in high-power systems. In this work, we derive a complete set of orthonormal wavefront slope polynomials for rectangular apertures and describe the modal method for obtaining wavefront representation with the aberration balancing property. Error propagation properties for the modal method are evaluated and compared with the Southwell method. The cross-coupling error is also discussed. Numerical experiments are conducted to illustrate that the modal method can achieve a higher accuracy than the Southwell method. In addition, we also investigate the influence of noise on the modal method compared with that of the Southwell method.

Purification and anticancer activity investigation of pentacyclic triterpenoids from the leaves of Sinojackia sarcocarpa L.Q. Luo by high-speed counter-current chromatography

Sinojackia sarcocarpa L.Q. Luo has high aesthetic value, which is clinically used to treat diseases such as the variations of arthritis, thromboangiitis obliterans, angina pectoris as well as many other diseases. Pentacyclic triterpenoids are the main pharmacological effective compounds. High-speed counter-current chromatography method was performed on a Midi-DE centrifuge at 25°C. The solvent system was n-hexane–ethylacetate–methanol–water (10 : 5 : 3 : 1, v/v). Peak fractions were collected according to the elution profile for subsequent high-performance liquid chromatography analysis. The structure identification was performed by ultraviolet, infrared, mass spectrometry, 1H-NMR and 13C-NMR. Compound 2α,3α,19β,23β-tetrahydroxyurs-12-en-28-oic acid and 2α,3α,23β-trihydroxyurs-12-en-28-oic acid were purified from the plant of Styracaceaen genius for the first time, whose purities were 96.57% and 97.33%, respectively. Compared with the same dose of oral 5-fluorouracil with 57.6% inhibition rate, the S180 tumour inhibition rates of 20 mg kg−1 d−1 two compounds were 59.5% and 48.9%, respectively.

Cloning of the gene encoding an insecticidal protein inPseudomonas pseudoalcaligenes

Pseudomonas pseudoalcaligenes strain PPA (first isolated from yellow-spined bamboo locust,Ceracris kiangsu, in 1991) is an effective biological control agent for locust.Escherichia coli DH5α was transformed using a partialSau3AI digest ofP. pseudoalcaligenes chromosomal DNA ligated withpUC19 vector cut byBamHI. The resulting genomic library was screened using an oligodeoxynucleotide probe derived from the N-terminal sequence of the purified insecticidal protein. Five positive clones were obtained after two rounds of screening. The 1.4 kbBamHI-KpnI fragment of the smallest clone (pSC1) contained the N terminal sequence of the insecticidal protein. Further sequencing identified an open reading frame encoding a polypeptide of 276 amino acid residues that is thought to contain a signal peptide of 22 amino acids and a mature protein of 254 amino acids. The calculated molecular weight of 26.7 kDa for the putative mature protein is close to that of the native insecticidal protein. The insecticidal protein lacked significant identity with toxic proteins from other bacteria upon comparison of amino acid sequences. ABamHI-KpnI fragment was cloned intopT7-6. A novel protein was expressed inE. coli BL21 (DE3) and its western blot similar to natural toxin.