Determination of the antibiotic fungicide validamycin A in formulated products by micellar electrokinetic chromatography.

A micellar electrokinetic capillary chromatographic method (MEKC) was used to determine validamycin A content in commercial products. The results indicated that this method was capable of analyzing the validamycin A content in formulated products with an instrument detection limit of 0.94 microg/mL and a method detection limit of 1. 70 microg/mL. Relative standard deviation (RSD) values of MEKC determination of validamycin A in formulated products ranged from 0. 61 to 2.09%. Recoveries of validamycin A in formulated products were in the region of 99.5-105.1%. All commercial products collected from markets contained validamycin A. The high percentage of recovery, the low detection limit, and the low RSD values confirmed that the MEKC technique is a senstivie and selective method.     

All hermaphrodite progeny are derived by self-pollinating the sunrise papaya mutant

Self‐pollination of a hermaphroditic cultivar normally gives a ratio of 2 : 1 hermaphrodite to female papayas with genotypes M₂m and mm, respectively. Much effort has been dedicated to marking the sexual types of papaya at the seedling stage to distinguish hermaphroditic from female papayas. A hermaphroditic papaya mutant (SR*) has been obtained, derived from the ‘Sunrise’ papaya cultivar mutant. Self‐pollination of the mutant resulted in all progenies being hermaphroditic. The genotype of the female was lethal, as a result of a lethal gene being linked to the mm female gene complex in this case. However, a 3 : 1 segregation ratio was obtained from the progeny of the hermaphroditic cultivar ‘Thailand’ crossed with SR*, indicating that all genotypes survived. Homozygous genotypes (M₂M₂) would be lethal according to Storey's model. Randomly selected F1 plants of the ‘Thailand’ SR* combination were self‐pollinated to obtain an F₂ generation. The F₂ segregation ratio suggested that the SR* mutant had a different form of the M₂ allele, now designated as M_@, which allowed the dominant M_@M₂ to survive in cross combinations. Genetic study has proved that SR* has the M_@ml genotype, a new mutant. It is capable of producing all hermaphroditic papaya progenies.     

Purification and characterization of acetylcholinesterase from oriental fruit fly [Bactrocera dorsalis (Hendel)] (Diptera: Tephritidae)

An acetylcholinesterase (AChE, EC 3.1.1.7) was purified from the head of the insecticide susceptible oriental fruit fly, Bactrocera dorsalis (Hendel), by affinity chromatography of Triton X-100 extract. The degree of purification was about 8183-fold with recoveries of 52%. The molecular mass of purified AChE was 116 kDa for its native protein (nonreduced form) and 61 kDa for its subunits (reduced form) as revealed on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), suggesting that the homodimer of AChE linked with disulfide bonds. Nondenaturing PAGE of the purified AChE revealed only one molecular form. The maximum velocities (V(max)) for hydrolyzing acetylthiocholine (ATC), propionylthiocholine, and S-butyrylthiocholine were 833.3, 222.2, and 57.5 micromol/min/mg, and the Michaelis constants (K(m)) were 87.9, 26.9, and 195.3 microM, respectively. More than 97% of AChE activity was inhibited by 10 microM eserine or BW284C51, but only 53% of the activity was inhibited by ethopropazine at the same concentration. On the basis of the substrate and inhibitor specificities, the purified enzyme appeared to be a true AChE. Nevertheless, the purified AChE exhibited some distinctive characteristics including (i) a lack of the substrate inhibition phenomenon when using ATC as the hydrolyzing substrate and (ii) a higher V(m) value for ATC than AChE from other insect species. These biochemical properties may show that AChE purified from the oriental fruit fly may have structural differences from those of other insect species.     

An impact of Deoxynivalenol produced by Fusarium graminearum on broiler chickens

Deoxynivalenol (DON) is a major mycotoxin from the trichothecene family of mycotoxins produced by Fusarium fungi that cause disease in grains. Food and feed contaminated with DON cause a variety of adverse health effects in humans and farm animals. However, the fermentation conditions of DON for toxicological study remain to be optimised. Deoxynivalenol levels were increased in a constant temperature of 20°C after fermentation for 7 and 14 days compared with cycling temperatures between 10–20°C and 15–20°C. We have established that optimum conditions for DON production on rice‐based medium is constant temperature at 20°C. In feeding experiments, the villus height and the ratio of villus height and crypt depth were reduced in the duodenum of DON‐fed broiler chickens, whereas a mycotoxin degradation agent efficiently reversed the abnormal morphology of the small intestine in the DON‐fed broilers. The expression of pro‐inflammatory gene, COX‐2, was induced in the spleen and bursa of Fabricius of DON‐fed broilers. This effect was alleviated in the presence of mycotoxin degradation agent. DON produced in solid‐state fermentation is able to cause toxic effects in broilers and induce an abnormal morphology of the small intestine, particularly the duodenum.     

A pair of shelled eggs inside a female dinosaur

An oviraptosaurian specimen (Dinosauria, Theropoda) from an Upper Cretaceous formation in China retains a pair of shelled eggs in the pelvis, providing direct evidence that oviraptorosaurian dinosaurs laid paired elongatoolithid eggs. The presence of the paired eggs suggests that theropod dinosaurs had two functional oviducts (like crocodiles) but that each oviduct produced only one egg at a time and that an entire egg clutch was laid through multiple ovipositions (like birds). The orientations of the eggs inside the skeleton and in clutches indicate that the mother came to the center of the nest to lay eggs.     

Speciation of Copper in Micropores

Speciation of copper in the micropores of zeolites and a contaminatedsoil was studied by extended X-ray absorption fine structural (EXAFS) spectroscopy. The Fourier transformed EXAFS data showed that copper oxide in zeolites ZSM-5 and ZSM-48 possessed a Cu-O bond distance of 1.95 Å with coordination numbers (CNs) of 1–2. Since ZSM-5 and ZSM-48 possessed channel openings of 5–6 Å, the possible sizes of the linear-type copper oxides in these confined pores were 2.93–2.95 Å. However, in the supercages (～13 Å) and channels (7.4 Å) of zeolite Y, a three dimensional structure of CuO was observed. Interestingly, we found that CuO in the Cu-contaminated soil had a similar structure to that in ZSM-5 or ZSM-48. Nevertheless, the EXAFS data indicated that the CNs of Cu-O and Cu-O-Cu were 0.4 and 0.3, respectively, suggesting a highly perturbed copper oxide in the irregular micropores of the contaminated soil.     

PTF 11kx: a type Ia supernova with a symbiotic nova progenitor

There is a consensus that type Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise nature of the binary companion remains uncertain. A temporal series of high-resolution optical spectra of the SN Ia PTF 11kx reveals a complex circumstellar environment that provides an unprecedentedly detailed view of the progenitor system. Multiple shells of circumstellar material are detected, and the SN ejecta are seen to interact with circumstellar material starting 59 days after the explosion. These features are best described by a symbiotic nova progenitor, similar to RS Ophiuchi.     

戊型肝炎病毒研究新进展

戊型肝炎病毒(hepatitis Evirus,HEV)是非甲非乙型急性肝炎的病原体,主要经粪-口途径传播,也有报道可以通过血液传播。戊型肝炎在亚洲、非洲及美洲的墨西哥等发展中国家常呈爆发流行,我国1986-1988年在新疆曾经发生戊型肝炎暴发流行[1],而在包括发达国家在内的世界各地呈散在传     

Toward an ideal animal model to trace donor cell fates after stem cell therapy: production of stably labeled multipotent mesenchymal stem cells from bone marrow of transgenic pigs harboring enhanced green fluorescence protein gene

The discovery of postnatal mesenchymal stem cells (MSC) with their general multipotentiality has fueled much interest in the development of cell-based therapies. Proper identification of transplanted MSC is crucial for evaluating donor cell distribution, differentiation, and migration. Lack of an efficient marker of transplanted MSC has precluded our understanding of MSC-related regenerative studies, especially in large animal models such as pigs. In the present study, we produced transgenic pigs harboring an enhanced green fluorescent protein (EGFP) gene. The pigs provide a reliable and reproducible source for obtaining stable EGFP-labeled MSC, which is very useful for donor cell tracking after transplantation. The undifferentiated EGFP-tagged MSC expressed a greater quantity of EGFP while maintaining MSC multipotentiality. These cells exhibited homogeneous surface epitopes and possessed classic trilineage differentiation potential into osteogenic, adipogenic, and chondrogenic lineages, with robust EGFP expression maintained in all differentiated progeny. Injection of donor MSC can dramatically increase the thickness of infarcted myocardium and improve cardiac function in mice. Moreover, the MSC, with their strong EGFP expression, can be easily distinguished from the background autofluorescence in myocardial infarcts. We demonstrated an efficient, effective, and easy way to identify MSC after long-term culture and transplantation. With the transgenic model, we were able to obtain stem or progenitor cells in earlier passages compared with the transfection of traceable markers into established MSC. Because the integration site of the transgene was the same for all cells, we lessened the potential for positional effects and the heterogeneity of the stem cells. The EGFP-transgenic pigs may serve as useful biomedical and agricultural models of somatic stem cell biology.