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581.
Algal bioassays were used to demonstrate the high efficiency of a comnbined tertiary wastewater treatment and marine aquaculture system in removing inorganic nitrogen, and to show that the coastal waters off Woods Hole, Massachusetts, are limited in nitrogen for marine phytoplankton growth. When nutrients were removed from secondarily treated domestic wastewater through assimilation by phytoplankton in an outdoor growth pond, the pond effluent, in varying dilutions with seawater, could not support more phytoplankton growth than the seawater alone. However, when nitrogen was added back to the mixtures of pond effluent and seawater, the phytoplankton growth response was similar to that with a mixture of wastewater and seawater. This is similar to the findings of other researchers, and suggests that nitrogen may be the key growth-limiting nutrient in many coastal marine waters. The combined tertiary treatment-marine aquaculture system appears to be an effective means of removing nitrogen from secondarily treated wastewater and controlling eutrophication of coastal marine waters. 相似文献
582.
Walsh T McClellan JM McCarthy SE Addington AM Pierce SB Cooper GM Nord AS Kusenda M Malhotra D Bhandari A Stray SM Rippey CF Roccanova P Makarov V Lakshmi B Findling RL Sikich L Stromberg T Merriman B Gogtay N Butler P Eckstrand K Noory L Gochman P Long R Chen Z Davis S Baker C Eichler EE Meltzer PS Nelson SF Singleton AB Lee MK Rapoport JL King MC Sebat J 《Science (New York, N.Y.)》2008,320(5875):539-543
Schizophrenia is a devastating neurodevelopmental disorder whose genetic influences remain elusive. We hypothesize that individually rare structural variants contribute to the illness. Microdeletions and microduplications >100 kilobases were identified by microarray comparative genomic hybridization of genomic DNA from 150 individuals with schizophrenia and 268 ancestry-matched controls. All variants were validated by high-resolution platforms. Novel deletions and duplications of genes were present in 5% of controls versus 15% of cases and 20% of young-onset cases, both highly significant differences. The association was independently replicated in patients with childhood-onset schizophrenia as compared with their parents. Mutations in cases disrupted genes disproportionately from signaling networks controlling neurodevelopment, including neuregulin and glutamate pathways. These results suggest that multiple, individually rare mutations altering genes in neurodevelopmental pathways contribute to schizophrenia. 相似文献
583.
Long-term ecosystem response to the Exxon Valdez oil spill 总被引:2,自引:0,他引:2
Peterson CH Rice SD Short JW Esler D Bodkin JL Ballachey BE Irons DB 《Science (New York, N.Y.)》2003,302(5653):2082-2086
The ecosystem response to the 1989 spill of oil from the Exxon Valdez into Prince William Sound, Alaska, shows that current practices for assessing ecological risks of oil in the oceans and, by extension, other toxic sources should be changed. Previously, it was assumed that impacts to populations derive almost exclusively from acute mortality. However, in the Alaskan coastal ecosystem, unexpected persistence of toxic subsurface oil and chronic exposures, even at sublethal levels, have continued to affect wildlife. Delayed population reductions and cascades of indirect effects postponed recovery. Development of ecosystem-based toxicology is required to understand and ultimately predict chronic, delayed, and indirect long-term risks and impacts. 相似文献
584.
585.
Donald R. Sumner Melvin R. Hall J. Danny Gay Greg MacDonald Stanley I. Savage R. Keith Bramwell 《Crop Protection》2002,21(10):963-972
The effect of continuous applications of poultry litter on root diseases, nematodes, and weeds with different tillage practices in vegetable production in Georgia was investigated. Litter treatments (noncomposted and composted broiler or breeder litter) applied 3–5 weeks before planting were compared with no litter. In sweet corn and snap bean there were differences among years, and tillage and litter treatments had a variable effect on yield, post-emergence damping-off and plant stand. Crown and brace root rot in corn induced by Rhizoctonia solani AG 2-2 increased after 3 years conservation tillage, but there were no differences among litter treatments. Population densities of R. solani AG-4 were increased by conservation tillage before planting snap bean the first year but not in later years, while litter treatments had no effect. After 3 years, populations of Pythium spp., Fusarium solani, and Fusarium spp. did not differ among treatments, but noncomposted broiler litter increased populations of saprophytic fungi in soil compared with no litter. Population densities of stylet-bearing nematodes were low and usually not different among treatments. After 3 years of sweet corn populations of Meloidogyne incognita increased with conventional tillage compared with conservation tillage, populations of Paratrichodorus christiei were reduced by litter treatments and populations of Helicotylenchus dihystera were reduced by noncomposted broiler litter compared with no litter. Weed infestation increased in both tillage systems with time, but in snap bean there was a greater infestation in conservation tillage than in conventional tillage. Litter treatments had little effect on weed infestation. 相似文献
586.
Stanley P. Kowalski Robert L. Plaisted John C. Steffens 《American Journal of Potato Research》1993,70(3):185-199
Type A glandular trichomes confer insect resistance to the wild potato,S. berthaultii Hawkes by oxidatively polymerizing their contents upon breakage, resulting in insect entrapment. Polyphenol oxidase (PPO) is responsible for the oxidative polymerization of Type A glandular trichome exudate.S. tuberosum L. trichomes possess low amounts of PPO and lack the ability to either polymerize their contents or entrap insects. Polyclonal antibodies raised against purifiedS. berthaultii glandular trichome PPO were used to develop an enzyme-linked immunosorbent assay (ELISA) to quantify PPO content ofS. berthaultii, S tuberosum, and hybrid type A glandular trichomes. The PPO ELISA and immunoblots were used to quantify PPO expression as a function of leaf development and genetic background. PPO accumulates to its maximal levels in trichomes prior to completion of leaflet expansion. In advanced breeding generations, trichome PPO is expressed at levels varying from that found inS. tuberosum to that found inS. berthaultii. By serving as an initial screen for trichome PPO, this ELISA may be useful to assist rapid introgression of this insect resistance trait into adaptedS. tuberosum backgrounds. 相似文献
587.
Dr R. L. Stanley M. E. Mccue S. J. Valberg J. R. Mickelson I. G. Mayhew C. Mcgowan C. N. Hahn J. C. Patterson‐Kane R. J. Piercy 《Equine veterinary journal》2009,41(6):597-601
Reasons for performing study: A glycogen synthase (GYS1) mutation has been described in horses with histopathological evidence of polysaccharide storage myopathy (PSSM) in the USA. It is unknown whether the same mutation is present in horses from the UK. Objectives: To determine whether the GYS1 mutation occurs in UK horses with histopathological evidence of PSSM and exertional rhabdomyolysis. Hypothesis: The R309H GYS1 mutation is present in a variety of UK horse breeds and that the mutation is commonly associated with exertional rhabdomyolysis. Methods: DNA was extracted from 47 muscle or blood samples from UK horses with histories of exertional rhabdomyolysis in which muscle biopsy diagnosis had been pursued. The proportions of GYS1 mutation positive cases were compared among histopathologically defined groups. In addition, breeds that carried the GYS1 mutation were identified from a total of 37 grade 2 (amylase‐resistant) PSSM cases. Results: Of 47 horses with exertional rhabdomyolysis in which a muscle biopsy diagnosis was pursued, 10 (21%) carried the GYS1 mutation. The mutation was only found in horses with grade 2 PSSM (i.e. not in horses with normal, idiopathic myopathy or grade 1 PSSM biopsy samples). In total, the GYS1 mutation was found in 24/37 (65%) of grade 2 PSSM cases. A variety of breeds, including Quarter Horse, Appaloosa, Warmblood, Connemara‐cross, Cob, Polo Pony and Thoroughbred cross carried the mutation. Conclusions: The GYS1 mutation is an important cause of exertional rhabdomyolysis of UK horse breeds but does not account for all forms of PSSM. Potential relevance: Genotyping is recommended in cases of exertional rhabdomyolysis, prior to or in combination with, muscle biopsy. However a significant proportion of horses with histopathological evidence of PSSM and/or exertional rhabdomyolysis have different diseases. 相似文献
588.
Thierry Olivry† Stanley M. Dunston Robina H. Walker Zeineb Alhaidari‡ Linda Messinger§ Zhi Liu† 《Veterinary dermatology》2009,20(1):42-50
In humans with pemphigus foliaceus (PF), pathogenic autoantibodies are principally of IgG4 subclass and they cause superficial vesiculation when injected into neonatal mice. The objectives of this study were to determine the isotypes of circulating antikeratinocyte antibodies in dogs with PF, to assess whether serum antikeratinocyte antibody titres decreased during successful treatment, and to study whether such antibodies were pathogenic in passive transfers. Using indirect immunofluorescence with neonatal mouse skin substrates, circulating antikeratinocyte IgG antibodies were detected in 36 of 44 dogs with PF (82%). Serum autoantibodies belonged predominantly to IgG4 (three of 44; 80%) and IgG1 (30 of 44; 68%) subclasses. Antikeratinocyte IgG antibodies were detected in 16 of 20 normal dogs (80%), and these antibodies were IgG1 (16 of 20, 80%) but rarely IgG4 (two of 20; 10%) isotypes. In four dogs, IgG4 antikeratinocyte antibody titres decreased concomitantly to lesions nearing or reaching complete remission. In contrast, IgG or IgG1 titres remained stable or increased when lesions abated. Antikeratinocyte antibodies targeted mainly intercellular autoantigen(s) in the stratum granulosum, while in fewer dogs, such antibodies bound to cytoplasmic basal antigen(s). Intradermal injections of PF or pemphigus vulgaris (PV) IgG into neonatal mice caused subgranular or suprabasal acantholytic vesiculation without granulocyte infiltration, respectively. Similar transfers of normal dog IgG did not cause vesiculation. These observations suggest that antikeratinocyte IgG4 antibodies could be relevant to disease pathogenesis. Importantly, canine PF or PV IgG appear to be pathogenic when transferred passively into mice, causing vesiculation at epidermal levels similar to those of the natural disease. 相似文献
589.
G. Craig Yencho Stanley P. Kowalski George G. Kennedy Lind L. Sanford 《American Journal of Potato Research》2000,77(3):167-178
Solanum chacoense Bitter is resistant to the Colorado potato beetle (CPB),Leptinotarsa decemlineata (Say). Resistance has been associated with the presence of a rare class of glycoalkaloids, the leptines. In this study, seven tetraploid, F2S. tuberosum xS. chacoense families were evaluated for foliar production of leptines I and II, leptinines I and II, and α-solanine and α-chaconine; and screened for resistance to CPB in the laboratory and field. Resistance was correlated with the concentrations of glycoalkaloids on a family and an individual basis. Leptine concentrations ranged from undetectable to a high of 18.0 mg/g dry weight. All of the progeny produced solanine and chaconine. Family 9623 had the highest mean leptine concentration and the lowest mean leaf disk feeding and CPB defoliation levels. Family 9616 had the lowest mean glycoalkaloid concentration and ranked as one of the most susceptible families. Regression analyses of solanine + chaconine, leptine I and II, and leptinine I and II foliar concentrations versus leaf disk consumption and field defoliation revealed that only increased foliar levels of leptines resulted in decreased CPB feeding. The regression models for leptines versus leaf disk consumption and field defoliation were highly significant, accounting for 17% and 26% of the variation in consumption and defoliation, respectively. To the best of our knowledge, this is the first work reporting the impact of leptine and leptinine concentrations on CPB feeding in tetraploid,S. tuberosum xS. chacoense potato hybrids. Results are discussed within the context of breeding for resistance to CPB. 相似文献
590.
The emphasis of plantation management changes as the resource and the market develop. This is especially the case when a plantation
program is developing a new timber resource, is not the case with many of the Pinus radiata (D. Don) plantings in the southern hemisphere. Australia establishes and manages plantations of both exotic conifer and native
hardwood (Eucalyptus spp.) plantations, and these vary in their stage of development. The tenure and objectives in establishment have varied,
but some key aspects of the resources may be analyzed. Optimization of production per unit area was not a prime objective
during the developmental stages of many exotic pine plantations. Currently, with increased commercial emphasis, this has changed
to a greater focus on increased value through Site Specific Management and tree improvement through which gains of at least
20 percent are expected during the first stages. With a key objective of sustainability, questions regarding impacts of soils,
water, and biological changes need consideration and are being addressed.
The eucalypt plantation resource in Australia is smaller in extent than is the pine resource, but of increasing importance,
especially as the plantations are perceived to be more environmentally and ecologically acceptable than exotic conifers. In
the past, questions of productivity, especially in relation to impacts of natural pests and diseases, have been raised. Sustainability
of all plantations is a critical aspect, however, for specific issues there are different emphases with different species.
For example, the relatively, high removal of calcium in smooth barked Eucalyptus plantations is seen as important in long
term forest management.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献