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61.
Fernandez-Gonzalez A La Spada AR Treadaway J Higdon JC Harris BS Sidman RL Morgan JI Zuo J 《Science (New York, N.Y.)》2002,295(5561):1904-1906
The classical recessive mouse mutant, Purkinje cell degeneration (pcd), exhibits adult-onset degeneration of cerebellar Purkinje neurons, retinal photoreceptors, olfactory bulb mitral neurons, and selected thalamic neurons, and has defective spermatogenesis. Here we identify Nna1 as the gene mutated in the original pcd and two additional pcd alleles (pcd2J and pcd3J). Nna1 encodes a putative nuclear protein containing a zinc carboxypeptidase domain initially identified by its induction in spinal motor neurons during axonal regeneration. The present study suggests an unexpected molecular link between neuronal degeneration and regeneration, and its results have potential implications for neurodegenerative diseases and male infertility. 相似文献
62.
Johnson AP Cleaves HJ Dworkin JP Glavin DP Lazcano A Bada JL 《Science (New York, N.Y.)》2008,322(5900):404
Miller's 1950s experiments used, besides the apparatus known in textbooks, one that generated a hot water mist in the spark flask, simulating a water vapor-rich volcanic eruption. We found the original extracts of this experiment in Miller's material and reanalyzed them. The volcanic apparatus produced a wider variety of amino acids than the classic one. Release of reduced gases in volcanic eruptions accompanied by lightning could have been common on the early Earth. Prebiotic compounds synthesized in these environments could have locally accumulated, where they could have undergone further processing. 相似文献
63.
Herd CD Blinova A Simkus DN Huang Y Tarozo R Alexander CM Gyngard F Nittler LR Cody GD Fogel ML Kebukawa Y Kilcoyne AL Hilts RW Slater GF Glavin DP Dworkin JP Callahan MP Elsila JE De Gregorio BT Stroud RM 《Science (New York, N.Y.)》2011,332(6035):1304-1307
The complex suite of organic materials in carbonaceous chondrite meteorites probably originally formed in the interstellar medium and/or the solar protoplanetary disk, but was subsequently modified in the meteorites' asteroidal parent bodies. The mechanisms of formation and modification are still very poorly understood. We carried out a systematic study of variations in the mineralogy, petrology, and soluble and insoluble organic matter in distinct fragments of the Tagish Lake meteorite. The variations correlate with indicators of parent body aqueous alteration. At least some molecules of prebiotic importance formed during the alteration. 相似文献
64.
Over half of the carnivorous plant species assessed by the International Union for the Conservation of Nature (IUCN) are listed as threatened (i.e. vulnerable, endangered, or critically endangered), but the threats to carnivorous plants have not previously been quantified systematically. In this review, we quantify the conservation threats to carnivorous plant taxa worldwide. Using the IUCN Red List, a literature search of Web of Knowledge, and the National Red Lists database, we collected data on the threats to 48 species of carnivorous plants from nine genera. The most common threat was habitat loss from agriculture, followed by the collection of wild plants, pollution, and natural systems modifications. A principal coordinate analysis revealed that species within a genus often faced similar threats, and an indicator species analysis found positive associations among species in the genus Sarracenia and agricultural activities, over-collection, invasive species, and pollution. Future research should further quantify the effects of pollution on carnivorous plants, and more thoroughly examine the potential role of carnivorous plants as indicator species for wetland health. More research is also needed to quantify the extinction risk for many carnivorous plants, as presently only around 17% of species have been assessed by the IUCN. Ensuring the conservation of carnivorous plants will help maintain the important ecosystem services they provide and prevent secondary extinctions of specialist species that rely on them. 相似文献
65.
Kuo PC Lin MC Chen GF Yiu TJ Tzen JT 《Journal of agricultural and food chemistry》2011,59(7):3214-3219
The methanol extract of sesame (Sesamum indicum) seeds was fractionated and purified with the assistance of conventional column chromatography to afford 29 compounds including seven furofuran lignans. Among these isolates, (+)-samin (1) was obtained from the natural source for the first time. In addition, (-)-asarinin (30) and sesamol (31) were generated by oxidative derivation from (+)-sesamolin (2) and (+)-sesamin (3), two abundant lignans found in sesame seeds. To evaluate their in vitro antioxidant potential, the seven isolated lignans (1-7) and the two derivatives (30 and 31) were examined for the scavenging activities on DPPH free radicals and superoxide anions. Moreover, the capability of chelating ferrous ions and reducing power of these sesame lignans were also measured. The results suggest that, besides the well-known sesamolin and sesamin, the minor sesame lignans (+)-(7S,8'R,8R)-acuminatolide (5), (-)-piperitol (6), and (+)-pinoresinol (7) are also adequate active ingredients and may be potential sources for nutritional and pharmacological utilization. 相似文献
66.
Objective To evaluate the effectiveness of topical nalbuphine or oral tramadol in the treatment of corneal pain in dogs. Animals studied Fourteen male Beagle dogs. Procedures Dogs were divided into three treatment groups and sedated with dexmedetomidine (5 μ/kg IV). A 4 mm corneal epithelial wound was created in the right eye (OD) of all dogs. Sedation was reversed with atipamazole IM. All dogs received pre/post ophthalmic examinations. Post operatively, Group NB (n = 5) received topical 1% preservative‐free nalbuphine OD q8 h and an oral placebo PO q8 h. Group TR (n = 5) received tramadol (4 mg/kg) PO q8 h and topical sterile saline OD q8 h. Group CNTRL (n = 4) received topical sterile saline OD q8 h and an oral placebo q8 h. All dogs received topical 0.3% gentamicin OD TID until healed. Dogs were pain scored using a pain scoring system modified from the University of Melbourne pain scale at 0, 1, 2, 4, and 6 h, then every 6 h by observers masked to treatment, until corneal wounds were healed. Treatment failure was recorded if cumulative pain scores were above a minimum threshold of acceptable pain and rescue analgesia of morphine (1.0 mg/kg IM) was administered subsequently. Result Four dogs in Group NB, one dog in Group TR, and two dogs in Group CNTRL required rescue analgesia. There was no significant difference in the incidence of treatment failure between groups (P = 0.184). Mean time to rescue was 9.16 h. All corneal wounds were healed by 84 h. Conclusions The results of this study suggest tramadol rather than nalbuphine should be further investigated for the treatment of corneal pain. 相似文献
67.
Fast BJ Ferrell JA MacDonald GE Sellers BA MacRae AW Krutz LJ Kline WN 《Pest management science》2011,67(7):825-830
BACKGROUND: Bahiagrass (Paspalum notatum Flueggé) is a poor host of several soilborne pests of vegetable crops; therefore vegetable crops are commonly grown in a rotation with bahiagrass pastures in Florida. The herbicide aminopyralid provides foliar and soil residual weed control and increases forage production in bahiagrass pastures; however, the soil residual activity of aminopyralid makes carryover injury likely in subsequent sensitive vegetable crops. Field research was conducted to determine the sensitivity of five vegetable crops to soil residues of aminopyralid. RESULTS: At an aminopyralid soil concentration of 0.2 µg kg?1 (the limit of quantitation for aminopyralid in this research), crop injury ratings were 48% (bell pepper), 67% (eggplant), 71% (tomato), 3% (muskmelon) and 3% (watermelon), and fruit yield losses (relative to the untreated control) at that concentration were 61, 64, 95, 8 and 14% in those respective crops. CONCLUSIONS: The crops included in this research were negatively affected by aminopyralid at soil concentrations less than the limit of quantitation (0.2 µg kg?1). Therefore, it was concluded that a field bioassay must be used to determine whether carryover injury will occur when these crops are planted on a site where aminopyralid has been previously applied. Copyright © 2011 Society of Chemical Industry 相似文献
68.
Most administrators and ecologists agree that reducing the levels of hazardous fuels on forests is essential to restore healthy watersheds and protect adjacent human communities. The current debate over the appropriateness, technique, and timing of treatments utilized to restore vegetation structure and composition is currently on-going at local, state, and national levels. To provide information for these forums, the efficacy of seven traditional silvicultural systems and two types of reserves used in the Sierra Nevada mixed conifer forests is evaluated in terms of vegetation structure, fuel bed characteristics, modeled fire behavior, and potential wildfire related mortality. The systems include old-growth reserve, young-growth reserve, thinning from below, individual tree selection, overstory removal, and four types of plantations. These are the most commonly used silvicultural systems and reserves on federal, state, and private lands in the western United States. Each silvicultural system or reserve had three replicates and varied in size from 15 to 25 ha; a systematic design of plots was used to collect tree and fuel information. The majority of the traditional silvicultural systems examined in this work (all plantation treatments, overstory removal, individual tree selection) did not effectively reduce potential fire behavior and effects, especially wildfire induced tree mortality at high and extreme fire weather conditions. Overall, thinning from below, and old-growth and young-growth reserves were more effective at reducing predicted tree mortality. 相似文献
69.
Lipid oxidation is a major deteriorative factor in meats. Sources of natural antioxidants that are as effective as commercially available antioxidants are desired. The objective of this research was to investigate honey as an inhibitor of lipid oxidation in ground poultry. The antioxidant content of different varieties of honey was investigated spectrophotometrically and honey's effectiveness in reducing oxidation of ground poultry determined by monitoring thiobarbituric acid reactive substances (TBARS). Buckwheat honey had the highest antioxidant content and acacia honey the lowest. Honeys of different floral sources differed in their protection against lipid oxidation. Buckwheat honey (5%, w/w) reduced TBARS approximately 70%, whereas acacia honey reduced TBARS approximately 34% at 3 days of storage at 4 degrees C. In comparison to butylated hydroxytoluene and tocopherol (0.02% of total fat), honey (at 5% of the weight of the meat) was much more effective at preventing oxidation. Honey has great potential as an antioxidant source and may result in greater acceptability of meat products and prevent negative health implications of oxidized meats. 相似文献
70.
Kelsey L Batson Hilda I Caldern Mike D Tokach Jason C Woodworth Robert D Goodband Steve S Dritz Joel M DeRouchey 《Journal of animal science》2021,99(5)
Two experiments were conducted to determine the effects of crude protein (CP) level in diets containing coarse wheat bran (CWB) with or without pharmacological levels of Zn (provided by zinc oxide: ZnO) on growth performance and fecal DM of nursery pigs. In experiment 1, 360 barrows (Line 200 × 400, DNA, Columbus, NE, initially 5.6 kg) were allotted to 1 of 6 dietary treatments from d 0 to 21 after weaning with 5 pigs per pen and 12 pens per treatment. Treatments included a positive control diet (21% CP) with 3,000 mg/kg Zn in phase 1 and 2,000 mg/kg in phase 2; negative control (21% CP) with 110 mg/kg added Zn, and 4 diets containing 4% CWB and 110 mg/kg added Zn formulated to contain 21%, 19.5%, 18%, or 16.5% CP. The 2 control diets and 21% CP CWB diet contained 1.40% standardized ileal digestible (SID) Lys in phase 1 and 1.35% SID Lys in phase 2, while the 19.5%, 18%, and 16.5% CP diets contained 1.33, 1.25 and 1.20% Lys, respectively, in both phases. Pigs fed the positive control diet containing pharmacological ZnO had increased (P < 0.05) ADG and G:F compared with the negative control and the 21% CP CWB diet. Reducing CP (concurrently with SID Lys) in diets containing CWB decreased ADG and G:F (linear, P = 0.002); however, fecal DM increased (linear, P = 0.005). In experiment 2, two groups of 300 and 350 pigs, initially 7.0 and 6.2 kg, respectively, were used with 5 pigs per pen and 26 pens per treatment. The objective was to determine if adding back essential AA would improve growth performance of pigs fed the low CP diets. All dietary treatments were fed for 13 days, contained 4% CWB, and consisted of: (1) positive control with 2,000 mg/kg of Zn and 21% CP (1.35% SID Lys); (2) no ZnO and 21% CP; and 3 diets with no ZnO formulated to 18% CP and (3) 1.2% SID Lys; (4) 1.35% SID Lys by the addition of feed grade amino acids (AA), and (5) diet 4 with non-essential amino acids (NEAA; Gly and Glu). Pigs fed 21% CP with ZnO had increased (P = 0.001) ADG compared to those fed 18% CP (1.35% SID Lys) with high levels of feed grade amino acids or those fed the reduced SID Lys (1.2%) diet. Overall, G:F was improved (P < 0.001) for pigs fed 21% CP diets and those fed the 18% CP diet with NEAA compared to pigs fed 1.2% SID Lys and pigs fed high levels of feed grade amino acids. Fecal DM was increased for pigs fed the reduced SID Lys diet. In summary, pharmacological levels of Zn improve pig growth performance, but reducing CP (and subsequently SID Lys) decreased nursery pig growth performance. 相似文献