Failure of FIV-infected cats to control Toxoplasma gondii correlates with reduced IL2, IL6, and IL12 and elevated IL10 expression by lymph node T cells     

Levy JK  Liang Y  Ritchey JW  Davidson MG  Tompkins WA  Tompkins MB 《Veterinary immunology and immunopathology》2004,98(1-2):101-111

Increased susceptibility to intracellular pathogens in HIV-infected individuals and FIV-infected cats is attributed to a defective T-helper 1 (Th1) immune response. However, little is known about specific cytokine responses to secondary pathogens. To address this question, control and FIV-infected cats were challenged with Toxoplasma gondii, and lymph node cells analyzed for cytokine mRNA expression. Twenty-four weeks post-FIV infection, prior to T. gondii challenge, IL2 and IL12 mRNAs were depressed, whereas IL10 and IFNgamma mRNAs were increased in CD4+ and CD8+ subsets. Following T. gondii challenge, control cats showed increased expression of IL2, IFNgamma, IL10, IL12, and IL6 mRNAs. In contrast, IL2, IL6, IFNgamma, and IL12 mRNAs were suppressed in FIV-T. gondii co-infected cats, whereas IL10 remained at the high prechallenge levels. IFNgamma and IL10 mRNAs were produced by both CD4+ and CD8+ cells in FIV-T. gondii cats. Elevated IL10 may suppress a Th1 cytokine response to T. gondii challenge.  相似文献   

Disturbance and species composition drive canopy structure and distribution of large trees in Olympic rainforests,USA     

Kramer  Russell D.  Sillett  Stephen C.  Kane  Van R.  Franklin  Jerry F. 《Landscape Ecology》2020,35(5):1107-1125

Landscape Ecology - Western Olympic valley bottoms, disturbed by alluvial processes, are dominated by Picea sitchensis and isolated cohorts of Pseudotsuga menziesii, while upland contexts,...  相似文献   

Reciprocal rewards stabilize cooperation in the mycorrhizal symbiosis     

Kiers ET  Duhamel M  Beesetty Y  Mensah JA  Franken O  Verbruggen E  Fellbaum CR  Kowalchuk GA  Hart MM  Bago A  Palmer TM  West SA  Vandenkoornhuyse P  Jansa J  Bücking H 《Science (New York, N.Y.)》2011,333(6044):880-882

Plants and their arbuscular mycorrhizal fungal symbionts interact in complex underground networks involving multiple partners. This increases the potential for exploitation and defection by individuals, raising the question of how partners maintain a fair, two-way transfer of resources. We manipulated cooperation in plants and fungal partners to show that plants can detect, discriminate, and reward the best fungal partners with more carbohydrates. In turn, their fungal partners enforce cooperation by increasing nutrient transfer only to those roots providing more carbohydrates. On the basis of these observations we conclude that, unlike many other mutualisms, the symbiont cannot be "enslaved." Rather, the mutualism is evolutionarily stable because control is bidirectional, and partners offering the best rate of exchange are rewarded.  相似文献   

Conservation biology. A renowned field station rises from the ashes     

Guo J 《Science (New York, N.Y.)》2008,320(5875):444-445

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Fluorescent guest molecules report ordered inner phase of host capsules in solution     

Dalgarno SJ  Tucker SA  Bassil DB  Atwood JL 《Science (New York, N.Y.)》2005,309(5743):2037-2039

Despite recent strides in the synthesis of elaborate nanometer-scale molecular hosts, the internal structure of these self-assembled cages remains ill characterized. We used fluorescent probe molecules, pyrene butyric acid (PBA), as guests in C-hexylpyrogallol[4]arene capsules to relay information about the chemical environment on the interior of the assemblies. Spectroscopic and single-crystal x-ray diffraction studies show that, in both solution and the solid state, the host can encapsulate two PBA guests and keep them well separated through specific interactions with the capsule walls.  相似文献   

American Indian values and their impact on tribal economic development     

Jerry D. Stubben 《Agriculture and Human Values》1991,8(3):53-62

This study uses 1990 data from seventy-three American Indian tribes to explore factors associated with the adoption of indi genous economic development plans on American Indian reservations. The analyses employing ordinary least squares analytical models posit that the existence of tribally owned and controlled businesses on or near the reservations and the presence of tribally owned farm and ranch operations are most critical in explaining the existence of such plans. A closer scrutiny of this result further suggests that the effect of tribal ownership and control of businesses is more pronounced than that of the existence of a tribally owned farm and ranch operation. The wider implications for comprehensive Indian policy are noted.  相似文献   

Agriculture. Sustainable biofuels redux     

Robertson GP  Dale VH  Doering OC  Hamburg SP  Melillo JM  Wander MM  Parton WJ  Adler PR  Barney JN  Cruse RM  Duke CS  Fearnside PM  Follett RF  Gibbs HK  Goldemberg J  Mladenoff DJ  Ojima D  Palmer MW  Sharpley A  Wallace L  Weathers KC  Wiens JA  Wilhelm WW 《Science (New York, N.Y.)》2008,322(5898):49-50

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Guest transport in a nonporous organic solid via dynamic van der Waals cooperativity     

Atwood JL  Barbour LJ  Jerga A  Schottel BL 《Science (New York, N.Y.)》2002,298(5595):1000-1002

A well-known organic host compound undergoes single-crystal-to-single-crystal phase transitions upon guest uptake and release. Despite a lack of porosity of the material, guest transport through the solid occurs readily until a thermodynamically stable structure is achieved. In order to actively facilitate this dynamic process, the host molecules undergo significant positional and/or orientational rearrangement. This transformation of the host lattice is triggered by weak van der Waals interactions between the molecular components. In order for the material to maintain its macroscopic integrity, extensive cooperativity must exist between the molecules throughout the crystal, such that rearrangement can occur in a well-orchestrated fashion. We demonstrate here that even weak dispersive forces can exert a profound influence over solid-state dynamics.  相似文献   

Treatment of Domestic Wastewater by Three Plant Species in Constructed Wetlands   总被引：1，自引：0，他引：1  

Coleman  Jerry  Hench  Keith  Garbutt  Keith  Sexstone  Alan  Bissonnette  Gary  Skousen  Jeff 《Water, air, and soil pollution》2001,128(3-4):283-295

Three common Appalachian plant species (Juncus effusus L., Scirpus validus L., and Typha latifolia L.) were planted into small-scale constructed wetlands receivingprimary treated wastewater. The experimental design includedtwo wetland gravel depths (45 and 60 cm) and five plantingtreatments (each species in monoculture, an equal mixture of the three species, and controls without vegetation), with two replicates per depth × planting combination. Inflow rates (19 L day^-1) and frequency (3 times day^-1) were designed to simulate full-scale constructed wetlands as currently used for domestic wastewater treatmentin West Virginia. Influent wastewater and the effluent from each wetland were sampled monthly for ten physical, chemical and biological parameters, and plant demographic measurements were made. After passing through these trough wetlands, the average of all treatments showed a 70% reduction in total suspended solids (TSS) and biochemical oxygen demand (BOD), 50 to 60% reduction in nitrogen (TKN), ammonia and phosphate, anda reduction of fecal coliforms by three orders of magnitude. Depth of gravel (45 or 60 cm) had little effect on wetland treatment ability, but did influence Typha and Scirpus growth patterns. Gravel alone provided significant wastewater treatment, but vegetation further improved many treatment efficiencies. Typha significantly out-performedJuncus and Scirpus both in growth and in effluent quality improvement. There was also some evidence that the species mixture out-performed species monocultures.Typhawas the superior competitor in mixtures, but a decline in Typha growth with distance from the influent pipe suggested that nutrients became limiting or toxicities may have developed.  相似文献   

Comparison of HPLC methods for determination of anthocyanins and anthocyanidins in bilberry extracts   总被引：3，自引：0，他引：3  

Zhang Z  Kou X  Fugal K  McLaughlin J 《Journal of agricultural and food chemistry》2004,52(4):688-691

An HPLC method and an acid hydrolysis HPLC method for the analysis of anthocyanins and anthocyanidins in bilberry extracts have been developed. The HPLC method coupled with a mass detector has identified 11 anthocyanins in bilberry extracts. The method provides anthocyanin profiles that are very useful in verifying the identity of botanical raw materials, monitoring the consistency of the raw material source, and quantitating the total anthocyanins. The acid hydrolysis HPLC method greatly simplifies the anthocyanin profile in bilberry samples and converts anthocyanins to five major anthocyanidin aglycones: delphinidin, cyanidin, petunidin, peonidin, and malvidin. Each of these aglycones can be separated completely and quantitated accurately with external standards. Various extraction and hydrolysis conditions were investigated, and the advantages and disadvantages of the HPLC and acid hydrolysis methods are discussed.  相似文献