天麻基因组微卫星特征分析与分子标记开发

该研究基于第二代测序技术建立了天麻的基因文库,筛选微卫星序列,并对微卫星位点的类型、丰度、长度、偏好性等进行了分析与比较;并为60条重复次数高的微卫星序列设计了引物,运用4个种群80个样本进行了PCR扩增和聚丙烯酰胺凝胶电泳检测。结果表明:(1)天麻基因组测序得到61 048条基因序列,检测出微卫星位点12 107个,其中二核苷酸重复最多、长度变异大。(2)设计的60对微卫星引物中的20对能扩增出清晰条带且有多态性,每个位点的复等位基因数(N_a)在4~14之间,平均为8.40;多态性信息含量(PIC)平均为0.77。该研究开发的天麻微卫星分子标记为开展天麻遗传学研究及种质资源鉴定等工作奠定了基础。     

Hydrogen-rich pure water prevents superoxide formation in brain slices of vitamin C-depleted SMP30/GNL knockout mice

Hydrogen is an established anti-oxidant that prevents acute oxidative stress. To clarify the mechanism of hydrogen’s effect in the brain, we administered hydrogen-rich pure water (H₂) to senescence marker protein-30 (SMP30)/gluconolactonase (GNL) knockout (KO) mice, which cannot synthesize vitamin C (VC), also a well-known anti-oxidant. These KO mice were divided into three groups; recipients of H₂, VC, or pure water (H₂O), administered for 33 days. VC levels in H₂ and H₂O groups were <6% of those in the VC group. Subsequently, superoxide formation during hypoxia-reoxygenation treatment of brain slices from these groups was estimated by a real-time biography imaging system, which models living brain tissues, with Lucigenin used as chemiluminescence probe for superoxide. A significant 27.2% less superoxide formed in the H₂ group subjected to ischemia-reperfusion than in the H₂O group. Thus hydrogen-rich pure water acts as an anti-oxidant in the brain slices and prevents superoxide formation.     

陆地棉主要产量相关性状的SSR标记关联分析

高产优质育种是我国棉花育种的主要目标。寻找与目标性状关联的分子标记,可克服常规育种的盲目性,提高分子标记辅助选择育种的准确性。本研究对118份陆地棉种质资源的衣分、单铃重、单株铃数及子指等4个产量相关性状进行2年2点的表型鉴定,并利用覆盖全基因组的、有多态性的214对SSR标记进行标记与性状的关联分析。结果表明:118份材料的4个产量相关性状表型变异丰富,平均变异系数的变幅在6.1%~19.1%之间,且在各环境中表现较为稳定;基因型分析表明,214对标记共检测到460个等位变异,基因多样性指数平均为0.5151,PIC值平均为0.4587,表明该批标记具有较多的等位变异数和较高的基因多样性;群体结构分析表明该批材料可分为4个亚群,且各类群中材料与地理来源无对应关系;关联分析结果显示,在显著条件下(-log10P1.3,P0.05),共有39个标记位点能够在2个及2个以上的环境中同时检测到,其中有4个标记位点同时与2个以上性状相关联,进一步比较发现,有7个位点与前人研究结果一致,其余32个位点为新发现的位点。研究结果可为陆地棉产量性状遗传改良的分子标记辅助选择提供理论依据。     

Patterns of green fluorescent protein expression in transgenic plants

Modified forms of genes encoding green fluorescent protein (GFP) can be macroscopically detected when expressed in whole plants. This technology has opened up new uses for GFP such as monitoring transgene presence and expression in the environment once it is linked or fused to a gene of interest. When whole-plant or whole-organ GFP visualization is required, GFP should be predictably expressed and reliably fluorescent. In this study the whole plant expression and fluorescence patterns of a mGFP5er gene driven by the cauliflower mosaic virus 35S promoter was studied in intact GFP-expressing transgenic tobacco (Nicotiana tabacum cv. Xanthi). It was shown that GFP synthesis levels in single plant organs were similar to GUS activity levels from published data when driven by the same promoter. Under the control of the 35S promoter, high expression of GFP can be used to visualize stems, young leaves, flowers, and organs where the 35S promoter is most active. Modified forms of GFP could replace GUS as the visual marker gene of choice.     

Analysis of the genetic diversity and population structure of Perinereis aibuhitensis in China using TRAP and AFLP markers

Perinereis aibuhitensis is found in the coastal waters of northwestern Pacific. Different ecotypes are distributed throughout the coastal sea beach based on their ecology and behavior, but relatively little is known about the population structure of this species. In this study, we estimated the genetic relationships within P. aibuhitensis using Target Region Amplified Polymorphisms (TRAP) and Amplified Fragment Length Polymorphisms (AFLP) that were derived from related populations on the coasts of China. All populations were uniquely fingerprinted using the TRAP and AFLP marker method. The mean genetic distance was estimated to be 0.1859 based on the TRAPs and AFLPs. Using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) by Molecular Evolutionary Genetics Analysis (MEGA) 6.06 software, Principal Coordinate Analysis (PCA) and STRUCTURE analysis, the phylogenetic tree of the ten P. aibuhitensis populations was separated into four major clusters; however, the mantel test indicated that there was no significant correlation between the genetic and geographical distances due to gene differentiation and gene flow (P > 0.005). The genetic diversity was low for P. aibuhitensis at the population level compared with the species level. Finally, an appropriate strategy for conserving the P. aibuhitensis germplasm is proposed.     

Expression of adiponectin receptor 1 in olfactory mucosa of mice

AdipoR1 and AdipoR2 are receptors for the adipocyte-derived hormone adiponectin, which is an important regulator of glucose and lipid metabolism, and which has also been implicated in the control of food intake and energy homeostasis. In the present study, we have demonstrated that AdipoR1 is expressed in mature sensory neurons of the olfactory mucosa of mice, in a pattern reminiscent of the olfactory marker protein. AdipoR1 expression levels in the olfactory mucosa have been observed to increase gradually during late embryogenesis until adulthood. No local expression of adiponectin has been detected in nasal tissues, indicating that serum adiponectin is the ligand for AdipoR1 in olfactory sensory neurons. As the serum adiponectin concentration is regulated depending on adipose tissue mass, with a reduction of adiponectin levels being seen in obesity, AdipoR1 function in the olfactory epithelium seems to be directly linked to the nutritional status of the body, suggesting a potential modulatory role for AdipoR1 in the adjustment of the olfactory system to energy balance requirements. This work was supported by the Forschungsfonds ZEM Tübingen/Hohenheim. Nicole Hass is recipient of a Peter und Traudl Engelhorn Stiftung scholarship.     

Optimal group positioning after a predator attack: the influence of speed, sex, and satiation within mobile whirligig swarms

The position of animals within fish shoals, bird flocks, andinsect swarms is related to individual differences in hunger,body size, and defenses. These differences relate to the waythat animals balance multiple selection pressures includingfood-distribution and predator-attack patterns. However, therole of drafting/slipstreaming (taking advantage of the vorticesof those in front of you) and sex on the position of individualswithin a polarized group has not been well studied. For example,although hungry fish have been found to prefer positions towardthe front of a shoal on average, the mitigating factors of sex,recent predator exposure, and drafting have not been factoredinto this response. We conducted a controlled laboratory experimentwith individually marked whirligig beetles (Coleoptera: Gyrinidae)where sex and feeding level were controlled and the positionof beetles in a polarized group (in a flow tank) was analyzedat 2 different water speeds after exposure to a simulated predator.It was predicted that males and females would balance foragingand predator avoidance needs differently, as suggested by sexualsegregation theory and that males might be likely to occupyfront positions because of greater energetic needs. We foundthat in slow water males were more likely to occupy front positions,whereas in fast water females did, suggesting a different trade-offbetween the sexes in the need to forage versus save energy (draft).Additionally, we found that in slow water it was the hungrymales that came to the group's front, whereas hungry femaleswere more likely to move back. These are some of the first observationsof the positional complexity with which individuals in congregationsdisplay, and several adaptive and nonadaptive explanations forthe observed patterns are suggested.     

Development of a molecular marker associated with Verticillium wilt resistance in diploid interspecific potato hybrids

Verticillium wilt (VW) is a widespread and serious potato (Solanum tuberosum) disease caused by the soilborne fungi Verticillium dahliae and V. albo-atrum. Breeding for VW resistance in potato is challenging due to ambiguous symptom expression, a lack of high throughput screening techniques, and variability in colonization by the fungus among and within plants. Genetic studies have identified major genes that confer resistance in diploid Solanum chacoense (V _c ) and interspecific hybrids (V _w and V _t ). However, to date, these genes have not been used to develop molecular markers for the identification of resistant clones. Tomato Ve1 and Ve2 gene sequence information was used to amplify candidate Ve gene orthologs from both resistant and susceptible diploid potato hybrids. A CAPS marker was generated to track VW resistance in a backcross population segregating for resistance. The marker was also tested for its usefulness in other breeding lines. Our results indicate that this marker is effective for selection of the V _w gene in segregating breeding populations.     

Genomic fingerprinting of Clostridium difficile isolates by using a random amplified polymorphic DNA (RAPD) assay

Abstract This study describes the use of a new and easy method called random amplfied polymorphic DNA (RAPD) assay to distinguish strains of C. difficile . We used two single short primers (AP4 and AP5) with arbitrary nucleotide sequences in a polymerase chain reaction to amplify genomic DNA. The profiles observed after electrophoretic separation were able to distinguish 20 reference C. difficile strains previously serotyped by Delmées method. The fingerprints of 11 epidemiologically unrelated C. diffiile strains clearly yielded a DNA polymorphism between all the strains. Latterly, RAPD profiles of 11 C. difficile strains isolated from 2 independant suspected outbreaks showed, in each case, a predominant banding pattern correponding to an epidemic strain. These results suggest that RAPD assay could be a valuable tool for epidemiological studies.     

TRP channels as potential drug targets

Calcium (Ca2+) is an ubiquitous intracellular signal that is responsible for a plethora of cellular processes including fertilization, secretion, contraction, neuronal signaling and learning. In addition, changes in intracellular Ca2+ have been known to influence cell proliferation and differentiation for more than three decades. Recent studies have indicated that members of the transient receptor potential (TRP) family of ion channels which respond to many different modes of stimulation both from within and outside the cell may be a primary mode of cation and Ca2+ entry into cells and may have roles in growth control. Moreover, changes in the expression of these channels may contribute to certain cancers. In the following, recent results concerning the expression and function of members of this family of ion channels are summarized.