小麦品种小偃6号染色体结构变异的细胞学研究

本文报道了小麦品种小偃6号的染色体结构变异。小偃6号及其亲缘品种与中国春小麦杂交,杂种F_1染色体配对资料表明:小偃6号及其父本小偃96与中国春在染色体结构上有很大差异。八倍体小偃麦小偃693与小偃6号和小偃96杂种F_1减数分裂中期出现19″+2′′′+5′的染色体构型,说明小偃6号和小偃96至少含有两个长穗偃麦草染色体片段。将小偃6号与中国春双端体系列杂交,杂种F_1中1AL、2AS、5AS、6AS和7BS端着丝点染色体配对频率极显著地低于(中国春×小偃6号)F_1的平均染色体臂配对频率(90.1％),从而将小偃6号中的异源片段局限于这5个染色体臂内;同时发现:1AL、2DS、4DS、6AL及3B(t″s+t′L)端体中的端着丝点染色体参与了杂种F_1中多价体的形成,或与此有关,故认为小偃6号与中国春至少有两个相互易位的差异,涉及到染色体1A、2D、3B、4D和6A。文章还对小偃6号异源易位的起源和鉴定等进行了讨论。     

Molecular cytogenetic identification and relationship of the artificial intergeneric hybrid between Dendranthema indica and Crossostephium chinense by GISH

Although most of the hybrid embryos aborted at an early developmental stage, a 2n = 27 true intergeneric hybrid between Dendranthema indica (L.) Des Moul (2n = 36) as ♀ and Crossostephium chinense (L.) Makino (2n = 18) as ♂ was produced following pollination and ovule rescue. The morphology of the resulting adult putative hybrid and the two parents differed significantly from one another in seven of the nine traits measured, the exceptions being leaf width and leaf length, for which the putative hybrid was indistinguishable from the maternal plant. Genomic in situ hybridization experiments were able to successfully distinguish the genomic origin of both mitotic and meiotic metaphase chromosomes in the hybrid. In addition, the 18 D. indica chromosomes were paired as bivalents at meiotic metaphase in the hybrid.     

The intestinal microbiome associated with lipid metabolism and obesity in humans and animals

Intestinal microbiota is considered to play an integral role in maintaining health of host by modulating several physiological functions including nutrition, metabolism and immunity. Accumulated data from human and animal studies indicate that intestinal microbes can affect lipid metabolism in host through various direct and indirect biological mechanisms. These mechanisms include the production of various signalling molecules by the intestinal microbiome, which exert a strong effect on lipid metabolism, bile secretion in the liver, reverse transport of cholesterol and energy expenditure and insulin sensitivity in peripheral tissues. This review discusses the findings of recent studies suggesting an emerging role of intestinal microbiota and its metabolites in regulating lipid metabolism and the association of intestinal microbiota with obesity. Additionally, we discuss the controversies and challenges in this research area. However, intestinal micro-organisms are also affected by some external factors, which in turn influence the regulation of microbial lipid metabolism. Therefore, we also discuss the effects of probiotics, prebiotics, diet structure, exercise and other factors on intestinal microbiological changes and lipid metabolism regulation.     

Cryptosporidium spp. in Wild,Laboratory, and Pet Rodents in China: Prevalence and Molecular Characterization

To understand the prevalence of Cryptosporidium infection in rodents in China and to assess the potential role of rodents as a source for human cryptosporidiosis, 723 specimens from 18 rodent species were collected from four provinces of China and examined between August 2007 and December 2008 by microscopy after using Sheather''s sugar flotation and modified acid-fast staining. Cryptosporidium oocysts were detected in 83 specimens, with an overall prevalence of 11.5%. Phodopus sungorus, Phodopus campbelli, and Rattus tanezumi were new reported hosts of Cryptosporidium. The genotypes and subtypes of Cryptosporidium strains in microscopy-positive specimens were further identified by PCR and sequence analysis of the small subunit rRNA and the 60-kDa glycoprotein (gp60) genes. In addition to Cryptosporidium parvum, C. muris, C. andersoni, C. wrairi, ferret genotype, and mouse genotype I, four new Cryptosporidium genotypes were identified, including the hamster genotype, chipmunk genotype III, and rat genotypes II and III. Mixed Cryptosporidium species/genotypes were found in 10.8% of Cryptosporidium-positive specimens. Sequence analysis of the gp60 gene showed that C. parvum strains in pet Siberian chipmunks and hamsters were all of the subtype IIdA15G1, which was found previously in a human isolate in The Netherlands and lambs in Spain. The gp60 sequences of C. wrairi and the Cryptosporidium ferret genotype and mouse genotype I were also obtained. These findings suggest that pet rodents may be potential reservoirs of zoonotic Cryptosporidium species and subtypes.Cryptosporidium spp. are protozoan parasites that infect a wide range of vertebrates, including humans. Cryptosporidiosis is acute and self-limiting in immunocompetent hosts but life threatening in immunocompromised individuals (48). Humans and animals can acquire Cryptosporidium infection through direct contact with infected individuals or contaminated fomites or by consumption of contaminated food or water (16, 47). Rodents, which are abundant and widespread, have been considered reservoirs of cryptosporidiosis in humans and farm animals. Previous studies based on oocyst morphology showed that many wild rodents might serve as hosts of Cryptosporidium parvum-like and C. muris-like parasites (4, 8, 42). The reported prevalence rates of Cryptosporidium in rodents ranged from 5.0% to 39.2% (11-13). Nearly 40 rodent species belonging to 11 families (Sciuridae, Muridae, Cricetidae, Castoridae, Geomyidae, Hystricidae, Erethizontidae, Myocastoridae, Caviidae, Hydrochoeridae, and Chinchillidae) have been reported as hosts of Cryptosporidium spp. (10, 12, 30, 53).Recently, PCR-based genotyping and subtyping tools have been used in assessing the human-infective potential of Cryptosporidium spp. in animals and the extent of cross-species transmission of cryptosporidiosis in animals (47, 49, 51). Five Cryptosporidium species and nearly 20 Cryptosporidium genotypes of uncertain species status have been identified in rodents worldwide in recent studies (3, 6, 12, 13, 18-20, 23, 26, 30, 31, 36, 39, 52, 53). Among them, C. parvum, C. meleagridis, cervine genotype, C. muris, C. andersoni, chipmunk genotype I, and skunk genotype have been associated with cryptosporidiosis in humans although the last four species and genotypes are each responsible for only one or a few cases (47). Subtyping based on sequence analysis of the 60-kDa glycoprotein (gp60) gene has been used in tracking the transmission of six Cryptosporidium species and genotypes, including C. hominis, C. parvum, C. meleagridis, C. fayeri, and the rabbit and horse genotypes (7, 37). There are at least 10 gp60 subtype families of C. parvum, two (IIa and IId) of which are involved in zoonotic transmission. In rodents, natural C. parvum infection is rare (11), and only one C. parvum subtype (IIaA15G2R1) has been reported in capybaras (Hydrochoerus hydrochaeris) in Brazil (30).Until recently there has been no genetic characterization of Cryptosporidium spp. in rodents in China. Worldwide, there are also hardly any genetic data on Cryptosporidium spp. from pet rodents. The purpose of this study was to determine the prevalence of Cryptosporidium in some wild, laboratory, and pet rodents in China and to assess the zoonotic potential of Cryptosporidium spp. from rodents.     

长穗偃麦草细胞质小麦核质杂种农艺性状的研究

长穗偃麦草细胞质小麦核质杂种与核共体进行了比较试验,结果证明：核质杂种株高降低５－８ｃｍ,抽穗期略有推迟,抗寒性有明显提高。其它农艺性状,如分蘖数,穗长,穗粒数,结实率等性状没有明显差异。但是在核质杂种中粒粒蛋白质含量增加了１１．７９％和２７．３３％,被分析的１７种氨基酸含量也是明显提高,提高幅度１２．３７－５３．０９％。     

Applications of magnetic surface imprinted materials for solid phase extraction of levofloxacin in serum samples

In this work, molecularly imprinted magnetic carbon nanotubes (MCNTs@MIPs) was prepared with surface imprinting technique for extraction of levofloxacin in serum samples. The preparation of molecularly imprinted polymers (MIPs) used levofloxacin as template, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross‐linker, and the magnetic carbon nanotubes (MCNTs) was synthesized by solvothermal method. The prepared polymers not only can be separated and collected easily by an external magnetic, but also exhibited high specific surface area and high selectivity to template molecules. Kinetic adsorption and static adsorption capacity investigations indicated that the synthesized MCNTs@MIPs had excellent recognition towards levofloxacin. Furthermore, magnetic solid phase extraction (MSPE) using the prepared MCNTs@MIPs as sorbent was then investigated, and an efficient sample cleanup was obtained with recoveries ranged from 78.7 ± 4.8 % to 83.4 ± 4.1%. In addition, several parameters, including the pH of samples, the amount of MCNTs@MIPs, the adsorption and desorption times, and the eluent, were investigated to obtain optimal extraction efficiency. Under the optimal extraction conditions, the stability of the polymer was also evaluated, and the average recovery reduced less than 7.6% after 5 cycles. MCNTs@MIPs successfully applied in the preconcentration and determination of levofloxacin in serum sample suggested that the MSPE method based on the novel polymers could be a promising alternative for selective and efficient extraction of trace amounts of pharmaceutical substances in bio‐matrix samples. Copyright © 2015 John Wiley & Sons, Ltd.