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Alexei V Evsikov Mary E Dolan Michael P Genrich Emily Patek Carol J Bult 《Genome biology》2009,10(8):R84-10
Linking biochemical genetic data to the reference genome for the laboratory mouse is important for comparative physiology
and for developing mouse models of human biology and disease. We describe here a new database of curated metabolic pathways
for the laboratory mouse called MouseCyc . MouseCyc has been integrated with genetic and genomic data for the laboratory mouse available from the Mouse Genome Informatics
database and with pathway data from other organisms, including human. 相似文献
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Ricci GC De Souza-Kaneshima AM Felismino MF Mendes-Bonato AB Pagliarini MS Do Valle CB 《Journal of genetics》2011,90(2):289-294
A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them,
15 accessions presented 2n = 18; 27 accessions, 2n = 36; and 2 accessions, 2n = 45 chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In
the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities
were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low
frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number
and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce
interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions. 相似文献
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Halie C Smith Devon J Niewohner Grant D Dewey Autumn M Longo Tracy L Guy Bradley R Higgins Sarah B Daehling Sarah C. Genrich Christopher D Wentworth Tessa L Durham Brooks 《Journal of visualized experiments : JoVE》2014,(83)
Research efforts in biology increasingly require use of methodologies that enable high-volume collection of high-resolution data. A challenge laboratories can face is the development and attainment of these methods. Observation of phenotypes in a process of interest is a typical objective of research labs studying gene function and this is often achieved through image capture. A particular process that is amenable to observation using imaging approaches is the corrective growth of a seedling root that has been displaced from alignment with the gravity vector. Imaging platforms used to measure the root gravitropic response can be expensive, relatively low in throughput, and/or labor intensive. These issues have been addressed by developing a high-throughput image capture method using inexpensive, yet high-resolution, flatbed scanners. Using this method, images can be captured every few minutes at 4,800 dpi. The current setup enables collection of 216 individual responses per day. The image data collected is of ample quality for image analysis applications. 相似文献
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信息素是生物体向外释放的化学物质,在细胞及生物体中具有种内信息传递的生理学功能。信息素这一类分子广泛分布于系统发生史中,它们的特异活性在单细胞生物、昆虫以及脊椎动物中均有报道。脊椎动物中信息素的信号传输已被证实是一嗅觉依赖过程,7TM-受体被认为是信号传输过程中的信号转换器。在低等单细胞生物(例如:来可夫游仆虫)的细胞膜上存在有信息素异构体,作为信息素分子的有效结合位点而行使其功能。本研究主要探讨单细胞的信息素(Er-1和Er-2)的基础细胞生理学作用是仅限于产生该信息素的物种,还是对其它的原生动物(例如:四膜虫)或对系统发育中分类地位较高的细胞(例如:MRC5成纤维细胞或J774巨噬细胞)均具有调节活性。研究结果表明,游仆虫的两种信息素对梨形四膜虫GL的生长调节有显著不同的作用:当信息素浓度为10-11M时,Er-1具有正调控作用,而Er-2具有抑制剂的作用。这两种配体的趋化作用也有很不同:Er-1具有一种广范的化学排斥特性,而Er-2具有一个双峰的化学吸引剂的性质。计算机检测发现,与Er-2的作用不同,Er-1可略微降低被测细胞的游动速率。趋化现象的选择特性表明Er-2信息素的受体有一种“短期”的特性;而Er-1是不能选择任何亚种群的,这也支持了我们先前的研究数据,即这两种信息素在四膜虫GL内产生两种不同的信号。四膜虫对信息素特异性的反应表明四膜虫能辨别非常近似但带有微小差异的配体(如Er-1和Er-2的电荷差异)。 相似文献
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The molecular mechanisms by which plants sense their micronutrient status, and adapt to their environment in order to ensure a sufficient micronutrient supply, are poorly understood. Zinc is an essential micronutrient for all living organisms. when facing a shortage in zinc supply, plants adapt by enhancing the zinc uptake capacity. The molecular regulators controlling this adaptation were recently identified. in this mini-review, we highlight recent progress in understanding the adaptation to zinc deficiency in plants and discuss the future challenges to fully unravel its molecular basis.Key words: adaptation, zinc deficiency, biofortification, molecular regulators, plant nutritionIn an increasingly populated world, agricultural production is an essential element of social development. Agriculture is the primary source of all nutrients required for human life, and nutrient sufficiency is the basis for good health and welfare of the human population.1 Soils with zinc deficiency are widespread in the world, affecting large areas of cultivated soils in India, Turkey, China, Brazil and Australia,2,3 making zinc the most common crop micronutrient deficiency.4 In addition, risk of inadequate zinc diet and zinc malnutrition are estimated to affect one-third of the global human population, i.e., around two billion people.5 Most affected are people living in developing countries, where diets are rich in cereal-based foods. Cereal grains are rich in phytate, which is a potent anti-nutrient, limiting micronutrient bioavailability.6 Zinc deficiency in crop production can be easily ameliorated through zinc fertilization, making agronomic biofortification an important strategy,3 however in the poorer regions, the required infrastructure to provide a reliable supply of zinc fertilizers of sufficient quality, is often not available. In those situations, biofortified crops, in which the zinc status of crops is genetically improved by selective breeding or via biotechnology, offer a rural-based intervention that will more likely reach the population.7 Different traits can be targeted to developing such improved crops, such as plant zinc deficiency tolerance, zinc use efficiency and the accumulation of zinc in edible parts. However, insufficient knowledge on the molecular mechanisms and the regulation of the zinc homeostasis network in plants is a serious bottleneck when pursuing zinc biofortification. 相似文献
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Rick PD; Hubbard GL; Kitaoka M; Nagaki H; Kinoshita T; Dowd S; Simplaceanu V; Ho C 《Glycobiology》1998,8(6):557-567
The polysaccharide chains of enterobacterial common antigen (ECA) consist
of linear trisaccharide repeat units with the structure -->3)-
alpha-d-Fuc4NAc-(1-->4)-beta-d-ManNAcA-(1-->
4)-alpha-d-GlcNAc-(1-->, where Fuc4NAc is 4-acetamido-4,
6-dideoxy-d-galactose, ManNAcA is N - acetyl-d- mannosaminuronic acid, and
GlcNAc is N -acetyl-d-glucosamine. The major form of ECA (ECAPG) consists
of polysaccharide chains that are believed to be covalently linked to
diacylglycerol through phosphodiester linkage; the phospholipid moiety
functions to anchor molecules in the outer membrane. The ECA trisaccharide
repeat unit is assembled as a polyisoprenyl-linked intermediate which has
been tentatively identified as Fuc4NAc-ManNAcA-GlcNAc-
pyrophosphorylundecaprenol (lipid III). Subsequent chain-elongation
presumably occurs by a block-polymerization mechanism. However, the
identity of the polyisoprenoid carrier-lipid has not been established.
Accordingly, the current studies were conducted in an effort to
structurally characterize the polyisoprenyl lipid-carrier involved in ECA
synthesis. Isolation and characterization of the lipid carrier was
facilitated by the accumulation of a ManNAcA-GlcNAc-
pyrophosphorylpolyisoprenyl lipid (lipid II) in mutants of Salmonella
typhimurium defective in the synthesis of TDP-Fuc4NAc, the donor of Fuc4NAc
residues for ECA synthesis. Analyses of lipid II preparations by fast atom
bombardment tandem mass spectroscopy (FAB-MS/MS) resulted in the
identification of the lipid-carrier as the 55-carbon polyisoprenyl alcohol,
undecaprenol. These analyses also resulted in the identification of a novel
glycolipid which copurified with lipid II. FAB-MS/MS analyses of this
glycolipid revealed its structure to be 1,2-diacyl- sn
-glycero-3-pryophosphoryl-GlcNAc-ManNAcA (DGP- disaccharide). An
examination of purified ECAPGby phosphorus-31 nuclear magnetic resonance
spectroscopy confirmed that the polysaccharide chains are linked to
diacylglycerol through phosphodiester linkage. Thus, DGP-disaccharide does
not appear to be an intermediate in ECAPGsynthesis. Nevertheless, although
the available evidence clearly indicate that lipid II is a precursor of
DGP-disaccharide, the function of this novel glycolipid is not yet known,
and it may be an intermediate in the biosynthesis of a molecule other than
ECAPG.
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