Citrus greening disease or huanglongbing(HLB)is associated with excessive pre-harvest fruit drop.To understand the mechanisms of the HLB-associated fruit abscission,transcriptomes were analyzed by RNA sequencing of ca...Citrus greening disease or huanglongbing(HLB)is associated with excessive pre-harvest fruit drop.To understand the mechanisms of the HLB-associated fruit abscission,transcriptomes were analyzed by RNA sequencing of calyx abscission zones(AZ-C)of dropped“Hamlin”oranges from HLB-diseased trees upon shaking the trees(Dd),retained oranges on diseased trees(Rd),dropped oranges from healthy shaken trees(Dh),and retained oranges on healthy trees(Rh).Cluster analysis of transcripts indicated that Dd had the largest distances from all other groups.Comparisons of transcriptomes revealed 1047,1599,813,and 764 differentially expressed genes(DEGs)between Dd/Rd,Dd/Dh,Dh/Rh,and Rd/Rh.The gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses indicated hormone signaling,defense response,and secondary metabolism were involved in HLB-associated fruit abscission.Ethylene(ET)and jasmonic acid(JA)synthesis/signaling-related genes were upregulated in Dd,while other phytohormone-related genes were generally downregulated.In addition,genes related to JA/ET-activated defense response were upregulated in Dd as well.Consistent with the phytohormone gene expression data,increased levels(p<0.05)of ET and JA,and a decreased level(p<0.05)of abscisic acid were found in Dd compared with Rd,Dh or Rh.Lasiodiploidia theobromae level in Dd AZ-C was higher than the other fruit types,confirmed by qPCR,indicating AZ-C secondary fungal infection of HLB fruit may exacerbate their abscission.This information will help formulate effective strategies to control HLB-related abscission.展开更多
Background The study objective was to test the hypothesis that low crude protein(CP)diet with crystalline amino acids(CAA)supplementation improves Lys utilization efficiency for milk production and reduces protein tur...Background The study objective was to test the hypothesis that low crude protein(CP)diet with crystalline amino acids(CAA)supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown.Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets(10.80 MJ/kg net energy):control(CON;19.24%CP)and reduced CP with“optimal”AA profile(OPT;14.00%CP).Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1,14,18,and 21 of lactation.Between d 14 and 18,a subset of 9 sows(CON=4,OPT=5)was infused with a mixed solution of 3-[methyl-2H3]histidine(bolus injection)and[13C]bicarbonate(priming dose)first,then a constant 2-h[13C]bicarbonate infusion followed by a 6-h primed constant[1-13C]lysine infusion.Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment,Lys oxidation rate,whole body protein turnover,and muscle protein breakdown.Results Over the 21-d lactation period,compared to CON,sows fed OPT had greater litter growth rate(P<0.05).Compared to CON,sows fed OPT had greater efficiency of Lys(P<0.05),Lys mammary flux(P<0.01)and whole-body protein turnover efficiency(P<0.05).Compared to CON,sows fed OPT tended to have lower whole body protein breakdown rate(P=0.069).Muscle protein breakdown rate did not differ between OPT and CON(P=0.197).Conclusion Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown.These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.展开更多
Differences exist in land use/cover pattern and its change between the P. R. China and the USA. In order to describe those differences, land use changes in representative regions were quantitatively analyzed and compa...Differences exist in land use/cover pattern and its change between the P. R. China and the USA. In order to describe those differences, land use changes in representative regions were quantitatively analyzed and compared. Xiamen City, Changzhutan region and Liupan Mountains regions were selected to represent three different hydrogeomorphic areas of eastern, central, and western China, respectively, while the Goodwin Creek Experimental Watershed (GCEW) located in the north-central part of Mississippi in the bluff hills just east of the Mississippi River floodplain was chosen in the USA. By integrating historical Landsat TM imagery and geographical information system data, the spatiotemporal land use dynamics and conversion of land use in China and the USA between 1980 and 2010 were explored and compared. Results indicated an urban sprawl in eastern and central China, which encroached upon large amount of cropland, forest land and grassland. On the other hand, western China reclaimed cropland from grassland, forest land, which led to severe soil erosion between 1990 and 2000. Goodwin Creek Watershed of the USA converted 73.3% of the lost cropland into forest land, pasture and idle land, which accounted for about 90% in 2010. Further, counter-urbanization occurs in the GCEW due to favorable eco-environment for living. Compared with the land dynamic degree of the GCEW, eastern China is greater than it;western China is smaller than it while central China is almost equal to it. And the land use intensity index of GCEW is smaller than that of China all these years. Eastern China advocated ecological civilization in 2007 to meet the serious challenges of sustainable development. Western China started the Return of Land from Farming to Forestry and Grassland Project in 2000. The Changzhutan region in central China is served as the resource-saving and environment-friendly community in 2007, which will be favorable for the sustainable land utilization and protection of ecology. From the eco-environmental view, China might use the experience of USA for future reference.展开更多
The demand for high strength fiber in rawcotton has increased because of the widespreaduse of high speed spinning technology in theyarn and textile industry.Improvement ofcotton fiber quality through
ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol...ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol acyltransferase （ACAT） activity. In the first experiment, 3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA, 1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake. In the second experiment, 4 groups of 6 early-weaned piglets were fed high-fat di- ets containing either 15% beef tallow, 12% beef tal- low plus 3% CLA, 15% corn oil, or 12% corn oil plus 3% CLA; fat provided 29% of energy intake. Cholesterol was balanced across diets in both experi-ments. In pigs fed the low-fat diets, all dietary fats in- creased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol （ HDL-C ） and very low-density lipoprotein cholesterol （VLDL-C）. LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets. However, ACAT activity was near- ly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets. All high-fat diets increased LDL-C, HDL-C and triacylglycerols equally with no effect on VLDL-C. There were no unique fat- ty acid effects of the high-fat diets on ACAT activity. We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C, but on- ly in pigs fed low-fat diets.展开更多
Plants have a perception system triggered by pathogen and pest signals to initiate defense.These signals include evolutionarily conserved molecules from microbes and insects termed pathogen/herbivore-associated molecu...Plants have a perception system triggered by pathogen and pest signals to initiate defense.These signals include evolutionarily conserved molecules from microbes and insects termed pathogen/herbivore-associated molecular patterns(PAMPs/HAMPs).Here we showed that hexaacetyl-chitohexaose(HC),an oligosaccharide from chitin,a structural component in insect exoskeletons and fungi cell walls,upregulated defense-associated genes WRKY22,GST1,RAR1,EDS1,PAL1 and NPR2,and downregulated ICS1 at 1 h after HC treatment in Sun Chu Sha mandarin leaves.The effect was transient as defense gene transcriptional changes were not observed at 18 h after the treatment.Electrical penetration graph(EPG)recordings were used to study the feeding behavior of Asian citrus psyllid(ACP)following the HC treatment.ACP is the hemipteran vector of Candidatus Liberibacter asiaticus(CLas),the pathogen associated with huanglongbing(HLB).Adult ACP displayed reduced intercellular probing,reduced xylem feeding count and duration,and increased non-probing activity on HC-treated citrus compared to controls.During an 18-h recording,percentage for total duration of xylem ingestion,phloem ingestion,intercellular probing were lower,and the percentage of nonprobing behavior was higher in HC-treated leaves than in controls.In host-selection behavior studies,HC treatment did not alter the attractiveness of citrus leaves under light or dark conditions.In addition,ACP feeding on HC-treated leaves did not show differences in mortality for up to 10 day of exposure.In summary,we report that HC induced a transient defense in citrus and an inhibitory effect on ACP feeding but did not affect host selection or the insect fitness under the tested conditions.展开更多
The high temperature and pressure achieved during cooking extrusion has been shown to affect nutrient availability. To determine the effects of extrusion temperature on the efficacy of mannanoligosaccharide (Bio-Mos?)...The high temperature and pressure achieved during cooking extrusion has been shown to affect nutrient availability. To determine the effects of extrusion temperature on the efficacy of mannanoligosaccharide (Bio-Mos?) in channel catfish, 4 experimental diets were fed for 9 wks and then challenged with Edwardsiella ictaluri bacterium. Catfish (9.9 ± 0.4 g) were randomly assigned to the following treatments: Low-None (low temperature process without additive);High-None (high temperature process without additive);Low-Bio (low temperature process with 4 g/kg diet Bio-Mos?);High-Bio (high temperature process with 4 g/kg diet Bio-Mos?). Although specific growth rate and food conversion ratio were similar among treatments (P > 0.10), survival after E. ictaluri challenge was highest (P ?-laden feed resulted in survival numbers similar to diets without Bio-Mos?. Extruding catfish diets supplemented with Bio-Mos? at lower temperatures may provide another strategy to control enteric septicemia of catfish.展开更多
BACKGROUND Antagonists of cannabinoid type 1 receptor(CB1)have been shown to promote body weight loss and improve insulin sensitivity.Cannabinoids decrease adiponectin,and CB1 blocker increase adiponectin.However,the ...BACKGROUND Antagonists of cannabinoid type 1 receptor(CB1)have been shown to promote body weight loss and improve insulin sensitivity.Cannabinoids decrease adiponectin,and CB1 blocker increase adiponectin.However,the mediators of CB1 actions are not well defined.AIM To investigate whether the beneficial effects of CB1 inhibition are,at least in part,mediated by adiponectin.METHODS We compared metabolic and inflammatory phenotypes of wild-type(WT)mice,CB1-null(CB1^(-/-))and CB1/adiponectin double-knockout(DKO)mice.We assessed the insulin sensitivity using insulin tolerance test and glucose tolerance test,and inflammation using flow cytometry analysis of macrophages.RESULTS CB1^(-/-)mice exhibited significantly reduced body weight and fat mass when compared to WT mice.While no significance was found in total daily food intake and locomotor activity,CB1^(-/-)mice showed increased energy expenditure,enhanced thermogenesis in brown adipose tissue(BAT),and improved insulin sensitivity compared to WT mice.DKO showed no difference in body weight,adiposity,nor insulin sensitivity;only showed a modestly elevated thermogenesis in BAT compared to CB1^(-/-)mice.The metabolic phenotype of DKO is largely similar to CB1^(-/-)mice,suggesting that adiponectin is not a key mediator of the metabolic effects of CB1.Interestingly,CB1^(-/-)mice showed reduced pro-inflammatory macrophage polarization in both peritoneal macrophages and adipose tissue macrophages compared to WT mice;in contrast,DKO mice exhibited increased pro-inflammatory macrophage polarization in these macrophages compared to CB1^(-/-)mice,suggesting that adiponectin is an important mediator of the inflammatory effect of CB1.CONCLUSION Our findings reveal that CB1 functions through both adiponectin-dependent and adiponectin-independent mechanisms:CB1 regulates energy metabolism in an adiponectin-independent manner,and inflammation in an adiponectin-dependent manner.The differential effects of adiponectin on CB1-mediated metabolic and inflammatory functions should be taken into consideration in CB1 antagonist utilization.展开更多
Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a bacterial disease of citrus and results in peel blemishes rendering fresh fruit unsalable. Xcc is most active in warm, wet Florida summers where tiss...Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a bacterial disease of citrus and results in peel blemishes rendering fresh fruit unsalable. Xcc is most active in warm, wet Florida summers where tissues are infected during periods of active growth. Melanose, caused by Diaporthe citri, is common in citrus producing countries, but, like canker, is only important for fresh market fruit. To control canker and melanose, Florida growers spray trees with copper formulations (Cu), but these sprays are removed by strong rains and intense radiation of Florida summers. A study was undertaken in FL commercial grapefruit groves in 2009 and 2010 to assess the efficiency of a spray combining copper with a specially formulated, hydrating wax (WashGard?) (WG). Using a 21-day spray schedule for the season, fruit were sprayed with WG + Cu, Cu and Control (no spray). Fruit from trees sprayed with WG + Cu had approximately 10 and17% more canker free fruit in 2009 and 2010 respectively compared to trees sprayed with copper alone. Compared to control trees the canker free fruit incidence was increased by ≈10% in 2009 and 57% in 2010. For melanose there was 40% more disease free fruit (treated) over fruit from trees with no treatment in 2009 and approximately 20% more in 2010. Controlling infection with this spray significantly reduces citrus canker and melanose, increasing the percentage of marketable fruit.展开更多
Cacao(Theobroma cacao L.)is an important Neotropical crop originating in South America and dispersed by European explorers,arriving in Madagascar in the late 19th century.Although Madagascar is an important producer o...Cacao(Theobroma cacao L.)is an important Neotropical crop originating in South America and dispersed by European explorers,arriving in Madagascar in the late 19th century.Although Madagascar is an important producer of cocoa for the premium chocolate market,the varietal composition and genetic diversity in cacao germplasm from Madagascar,especially in traditional cacao farms,remains unknown.A total of 190 cacao accessions,including 40 farmer accessions collected from traditional cacao farms in Madagascar,and 150 accessions representing seven reference cacao populations,were analyzed using Single Nucleotide Polymorphism(SNP)markers.Multivariate analysis and Bayesian stratification resulted in the clustering of the 40 farmer accessions into three groups:Criollo,Amelonado and Trinitario.These three traditional varieties were commonly cultivated in tropical America in the 18th century,but most of them have been replaced by improved varieties.The present study demonstrated that Madagascar is distinctive in that all three traditional cacao varieties,Criollo,Amelonado and Trinitario,are still maintained on-farm for cocoa production,as in Mesoamerica and the Caribbean several hundred years ago.Results from the present study are significant in terms of understanding the early dispersal of cacao from tropical America and Asia to Africa,in addition to the well-documented route from Brazil to São Tomé&Príncipe.The results also provide new information for planning future conservation and utilization of cacao germplasm in Madagascar.展开更多
Arbuscular mycorrhizal(AM)fungi contribute globally to ecosystem services and play an important role in sustainable crop production.However,it is unclear which factors contribute most to their colonization and communi...Arbuscular mycorrhizal(AM)fungi contribute globally to ecosystem services and play an important role in sustainable crop production.However,it is unclear which factors contribute most to their colonization and community structure at different sites,particularly in understudied ecosystems.This study investigated the AM fungal communities associated with switchgrass(Panicum virgatum L.)in the understudied acidic and oligotrophic pine barrens ecosystem using next-generation sequencing.Switchgrass was also sampled from agroecosystems,as well as,from a native prairie for comparison.The pine barrens switchgrass harbored a distinct AM fungal community−Acaulospora and Ambispora were almost exclusively found in the pine barrens sites,and some of these species may represent undescribed taxa.Glomus was the most ubiquitous AM fungal genus recovered from all sites.This study suggests differences in the AM fungal community structure under different soil properties and land uses.This is the first sequence-based report of the AM fungal communities in the pine barrens ecosystem.展开更多
对基于空间可分辨光谱的番茄成熟度分类判别方法进行了试验研究。首先根据番茄的内部颜色,将600个番茄分为6个不同成熟度(green,breaker,turning,pink,light red and red),然后用自行开发的多通道高光谱成像探头采集番茄的空间可分辨(SR...对基于空间可分辨光谱的番茄成熟度分类判别方法进行了试验研究。首先根据番茄的内部颜色,将600个番茄分为6个不同成熟度(green,breaker,turning,pink,light red and red),然后用自行开发的多通道高光谱成像探头采集番茄的空间可分辨(SR)光谱,建立基于空间可分辨光谱的番茄成熟度偏最小二乘判别(PLSDA)模型和支持向量机判别(SVMDA)模型。结果显示,对于PLSDA模型,SR光谱15为最佳分类光谱,分类正确率达到81.3%;对于SVMDA模型,SR光谱10为最佳预测分类光谱,分类正确率为86.3%。对六个成熟度等级番茄的判别分类,SVMDA模型要明显优于PLSDA模型。此外,相对于较小的光源-检测器距离SR光谱,较大的光源-检测器距离SR光谱可以获得更好的判别效果,显示出空间可分辨光谱在果蔬品质检测方面的应用潜力。展开更多
基金supported by Southern Gardens Citrus Nursery LLC,a subsidiary company of US Sugar Corporation.
文摘Citrus greening disease or huanglongbing(HLB)is associated with excessive pre-harvest fruit drop.To understand the mechanisms of the HLB-associated fruit abscission,transcriptomes were analyzed by RNA sequencing of calyx abscission zones(AZ-C)of dropped“Hamlin”oranges from HLB-diseased trees upon shaking the trees(Dd),retained oranges on diseased trees(Rd),dropped oranges from healthy shaken trees(Dh),and retained oranges on healthy trees(Rh).Cluster analysis of transcripts indicated that Dd had the largest distances from all other groups.Comparisons of transcriptomes revealed 1047,1599,813,and 764 differentially expressed genes(DEGs)between Dd/Rd,Dd/Dh,Dh/Rh,and Rd/Rh.The gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses indicated hormone signaling,defense response,and secondary metabolism were involved in HLB-associated fruit abscission.Ethylene(ET)and jasmonic acid(JA)synthesis/signaling-related genes were upregulated in Dd,while other phytohormone-related genes were generally downregulated.In addition,genes related to JA/ET-activated defense response were upregulated in Dd as well.Consistent with the phytohormone gene expression data,increased levels(p<0.05)of ET and JA,and a decreased level(p<0.05)of abscisic acid were found in Dd compared with Rd,Dh or Rh.Lasiodiploidia theobromae level in Dd AZ-C was higher than the other fruit types,confirmed by qPCR,indicating AZ-C secondary fungal infection of HLB fruit may exacerbate their abscission.This information will help formulate effective strategies to control HLB-related abscission.
基金financially supported by funds from the USDA-NIFA(award number 2014-67015-21832)。
文摘Background The study objective was to test the hypothesis that low crude protein(CP)diet with crystalline amino acids(CAA)supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown.Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets(10.80 MJ/kg net energy):control(CON;19.24%CP)and reduced CP with“optimal”AA profile(OPT;14.00%CP).Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1,14,18,and 21 of lactation.Between d 14 and 18,a subset of 9 sows(CON=4,OPT=5)was infused with a mixed solution of 3-[methyl-2H3]histidine(bolus injection)and[13C]bicarbonate(priming dose)first,then a constant 2-h[13C]bicarbonate infusion followed by a 6-h primed constant[1-13C]lysine infusion.Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment,Lys oxidation rate,whole body protein turnover,and muscle protein breakdown.Results Over the 21-d lactation period,compared to CON,sows fed OPT had greater litter growth rate(P<0.05).Compared to CON,sows fed OPT had greater efficiency of Lys(P<0.05),Lys mammary flux(P<0.01)and whole-body protein turnover efficiency(P<0.05).Compared to CON,sows fed OPT tended to have lower whole body protein breakdown rate(P=0.069).Muscle protein breakdown rate did not differ between OPT and CON(P=0.197).Conclusion Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown.These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.
基金supported by program of United States Department of Agriculture(Agreement Number:58-6408-3-001FN).
文摘Differences exist in land use/cover pattern and its change between the P. R. China and the USA. In order to describe those differences, land use changes in representative regions were quantitatively analyzed and compared. Xiamen City, Changzhutan region and Liupan Mountains regions were selected to represent three different hydrogeomorphic areas of eastern, central, and western China, respectively, while the Goodwin Creek Experimental Watershed (GCEW) located in the north-central part of Mississippi in the bluff hills just east of the Mississippi River floodplain was chosen in the USA. By integrating historical Landsat TM imagery and geographical information system data, the spatiotemporal land use dynamics and conversion of land use in China and the USA between 1980 and 2010 were explored and compared. Results indicated an urban sprawl in eastern and central China, which encroached upon large amount of cropland, forest land and grassland. On the other hand, western China reclaimed cropland from grassland, forest land, which led to severe soil erosion between 1990 and 2000. Goodwin Creek Watershed of the USA converted 73.3% of the lost cropland into forest land, pasture and idle land, which accounted for about 90% in 2010. Further, counter-urbanization occurs in the GCEW due to favorable eco-environment for living. Compared with the land dynamic degree of the GCEW, eastern China is greater than it;western China is smaller than it while central China is almost equal to it. And the land use intensity index of GCEW is smaller than that of China all these years. Eastern China advocated ecological civilization in 2007 to meet the serious challenges of sustainable development. Western China started the Return of Land from Farming to Forestry and Grassland Project in 2000. The Changzhutan region in central China is served as the resource-saving and environment-friendly community in 2007, which will be favorable for the sustainable land utilization and protection of ecology. From the eco-environmental view, China might use the experience of USA for future reference.
文摘The demand for high strength fiber in rawcotton has increased because of the widespreaduse of high speed spinning technology in theyarn and textile industry.Improvement ofcotton fiber quality through
基金Supported by USDA/CSREES Competitive Grant 98-35206-6286federal funds from the USDA,ARS under Cooperative Agreement no.58-6250-1-003
文摘ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol acyltransferase （ACAT） activity. In the first experiment, 3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA, 1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake. In the second experiment, 4 groups of 6 early-weaned piglets were fed high-fat di- ets containing either 15% beef tallow, 12% beef tal- low plus 3% CLA, 15% corn oil, or 12% corn oil plus 3% CLA; fat provided 29% of energy intake. Cholesterol was balanced across diets in both experi-ments. In pigs fed the low-fat diets, all dietary fats in- creased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol （ HDL-C ） and very low-density lipoprotein cholesterol （VLDL-C）. LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets. However, ACAT activity was near- ly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets. All high-fat diets increased LDL-C, HDL-C and triacylglycerols equally with no effect on VLDL-C. There were no unique fat- ty acid effects of the high-fat diets on ACAT activity. We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C, but on- ly in pigs fed low-fat diets.
基金Funding was provided by the Citrus Research and Development Foundation(CRDF),Inc.,Lake Alfred,FL,USA.
文摘Plants have a perception system triggered by pathogen and pest signals to initiate defense.These signals include evolutionarily conserved molecules from microbes and insects termed pathogen/herbivore-associated molecular patterns(PAMPs/HAMPs).Here we showed that hexaacetyl-chitohexaose(HC),an oligosaccharide from chitin,a structural component in insect exoskeletons and fungi cell walls,upregulated defense-associated genes WRKY22,GST1,RAR1,EDS1,PAL1 and NPR2,and downregulated ICS1 at 1 h after HC treatment in Sun Chu Sha mandarin leaves.The effect was transient as defense gene transcriptional changes were not observed at 18 h after the treatment.Electrical penetration graph(EPG)recordings were used to study the feeding behavior of Asian citrus psyllid(ACP)following the HC treatment.ACP is the hemipteran vector of Candidatus Liberibacter asiaticus(CLas),the pathogen associated with huanglongbing(HLB).Adult ACP displayed reduced intercellular probing,reduced xylem feeding count and duration,and increased non-probing activity on HC-treated citrus compared to controls.During an 18-h recording,percentage for total duration of xylem ingestion,phloem ingestion,intercellular probing were lower,and the percentage of nonprobing behavior was higher in HC-treated leaves than in controls.In host-selection behavior studies,HC treatment did not alter the attractiveness of citrus leaves under light or dark conditions.In addition,ACP feeding on HC-treated leaves did not show differences in mortality for up to 10 day of exposure.In summary,we report that HC induced a transient defense in citrus and an inhibitory effect on ACP feeding but did not affect host selection or the insect fitness under the tested conditions.
文摘The high temperature and pressure achieved during cooking extrusion has been shown to affect nutrient availability. To determine the effects of extrusion temperature on the efficacy of mannanoligosaccharide (Bio-Mos?) in channel catfish, 4 experimental diets were fed for 9 wks and then challenged with Edwardsiella ictaluri bacterium. Catfish (9.9 ± 0.4 g) were randomly assigned to the following treatments: Low-None (low temperature process without additive);High-None (high temperature process without additive);Low-Bio (low temperature process with 4 g/kg diet Bio-Mos?);High-Bio (high temperature process with 4 g/kg diet Bio-Mos?). Although specific growth rate and food conversion ratio were similar among treatments (P > 0.10), survival after E. ictaluri challenge was highest (P ?-laden feed resulted in survival numbers similar to diets without Bio-Mos?. Extruding catfish diets supplemented with Bio-Mos? at lower temperatures may provide another strategy to control enteric septicemia of catfish.
基金Supported by the NIH,No.DK118334 and No.AG064869and the BrightFocus,No.A2019630S(to Sun Y).
文摘BACKGROUND Antagonists of cannabinoid type 1 receptor(CB1)have been shown to promote body weight loss and improve insulin sensitivity.Cannabinoids decrease adiponectin,and CB1 blocker increase adiponectin.However,the mediators of CB1 actions are not well defined.AIM To investigate whether the beneficial effects of CB1 inhibition are,at least in part,mediated by adiponectin.METHODS We compared metabolic and inflammatory phenotypes of wild-type(WT)mice,CB1-null(CB1^(-/-))and CB1/adiponectin double-knockout(DKO)mice.We assessed the insulin sensitivity using insulin tolerance test and glucose tolerance test,and inflammation using flow cytometry analysis of macrophages.RESULTS CB1^(-/-)mice exhibited significantly reduced body weight and fat mass when compared to WT mice.While no significance was found in total daily food intake and locomotor activity,CB1^(-/-)mice showed increased energy expenditure,enhanced thermogenesis in brown adipose tissue(BAT),and improved insulin sensitivity compared to WT mice.DKO showed no difference in body weight,adiposity,nor insulin sensitivity;only showed a modestly elevated thermogenesis in BAT compared to CB1^(-/-)mice.The metabolic phenotype of DKO is largely similar to CB1^(-/-)mice,suggesting that adiponectin is not a key mediator of the metabolic effects of CB1.Interestingly,CB1^(-/-)mice showed reduced pro-inflammatory macrophage polarization in both peritoneal macrophages and adipose tissue macrophages compared to WT mice;in contrast,DKO mice exhibited increased pro-inflammatory macrophage polarization in these macrophages compared to CB1^(-/-)mice,suggesting that adiponectin is an important mediator of the inflammatory effect of CB1.CONCLUSION Our findings reveal that CB1 functions through both adiponectin-dependent and adiponectin-independent mechanisms:CB1 regulates energy metabolism in an adiponectin-independent manner,and inflammation in an adiponectin-dependent manner.The differential effects of adiponectin on CB1-mediated metabolic and inflammatory functions should be taken into consideration in CB1 antagonist utilization.
文摘Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is a bacterial disease of citrus and results in peel blemishes rendering fresh fruit unsalable. Xcc is most active in warm, wet Florida summers where tissues are infected during periods of active growth. Melanose, caused by Diaporthe citri, is common in citrus producing countries, but, like canker, is only important for fresh market fruit. To control canker and melanose, Florida growers spray trees with copper formulations (Cu), but these sprays are removed by strong rains and intense radiation of Florida summers. A study was undertaken in FL commercial grapefruit groves in 2009 and 2010 to assess the efficiency of a spray combining copper with a specially formulated, hydrating wax (WashGard?) (WG). Using a 21-day spray schedule for the season, fruit were sprayed with WG + Cu, Cu and Control (no spray). Fruit from trees sprayed with WG + Cu had approximately 10 and17% more canker free fruit in 2009 and 2010 respectively compared to trees sprayed with copper alone. Compared to control trees the canker free fruit incidence was increased by ≈10% in 2009 and 57% in 2010. For melanose there was 40% more disease free fruit (treated) over fruit from trees with no treatment in 2009 and approximately 20% more in 2010. Controlling infection with this spray significantly reduces citrus canker and melanose, increasing the percentage of marketable fruit.
文摘Cacao(Theobroma cacao L.)is an important Neotropical crop originating in South America and dispersed by European explorers,arriving in Madagascar in the late 19th century.Although Madagascar is an important producer of cocoa for the premium chocolate market,the varietal composition and genetic diversity in cacao germplasm from Madagascar,especially in traditional cacao farms,remains unknown.A total of 190 cacao accessions,including 40 farmer accessions collected from traditional cacao farms in Madagascar,and 150 accessions representing seven reference cacao populations,were analyzed using Single Nucleotide Polymorphism(SNP)markers.Multivariate analysis and Bayesian stratification resulted in the clustering of the 40 farmer accessions into three groups:Criollo,Amelonado and Trinitario.These three traditional varieties were commonly cultivated in tropical America in the 18th century,but most of them have been replaced by improved varieties.The present study demonstrated that Madagascar is distinctive in that all three traditional cacao varieties,Criollo,Amelonado and Trinitario,are still maintained on-farm for cocoa production,as in Mesoamerica and the Caribbean several hundred years ago.Results from the present study are significant in terms of understanding the early dispersal of cacao from tropical America and Asia to Africa,in addition to the well-documented route from Brazil to São Tomé&Príncipe.The results also provide new information for planning future conservation and utilization of cacao germplasm in Madagascar.
基金supported by the National Science Foundation(grant number DEB 1452971)Rutgers Alberts Research Awards in Biodiversity,Rutgers Center for Turfgrass Science and the New Jersey Agricultural Experiment Station to N.Zhangthe National Military Family Association,and the Garden Club of America。
文摘Arbuscular mycorrhizal(AM)fungi contribute globally to ecosystem services and play an important role in sustainable crop production.However,it is unclear which factors contribute most to their colonization and community structure at different sites,particularly in understudied ecosystems.This study investigated the AM fungal communities associated with switchgrass(Panicum virgatum L.)in the understudied acidic and oligotrophic pine barrens ecosystem using next-generation sequencing.Switchgrass was also sampled from agroecosystems,as well as,from a native prairie for comparison.The pine barrens switchgrass harbored a distinct AM fungal community−Acaulospora and Ambispora were almost exclusively found in the pine barrens sites,and some of these species may represent undescribed taxa.Glomus was the most ubiquitous AM fungal genus recovered from all sites.This study suggests differences in the AM fungal community structure under different soil properties and land uses.This is the first sequence-based report of the AM fungal communities in the pine barrens ecosystem.
文摘对基于空间可分辨光谱的番茄成熟度分类判别方法进行了试验研究。首先根据番茄的内部颜色,将600个番茄分为6个不同成熟度(green,breaker,turning,pink,light red and red),然后用自行开发的多通道高光谱成像探头采集番茄的空间可分辨(SR)光谱,建立基于空间可分辨光谱的番茄成熟度偏最小二乘判别(PLSDA)模型和支持向量机判别(SVMDA)模型。结果显示,对于PLSDA模型,SR光谱15为最佳分类光谱,分类正确率达到81.3%;对于SVMDA模型,SR光谱10为最佳预测分类光谱,分类正确率为86.3%。对六个成熟度等级番茄的判别分类,SVMDA模型要明显优于PLSDA模型。此外,相对于较小的光源-检测器距离SR光谱,较大的光源-检测器距离SR光谱可以获得更好的判别效果,显示出空间可分辨光谱在果蔬品质检测方面的应用潜力。
