The further evolution of cooperation   总被引：1，自引：0，他引：1  

Axelrod R  Dion D 《Science (New York, N.Y.)》1988,242(4884):1385-1390

Axelrod's model of the evolution of cooperation was based on the iterated Prisoner's Dilemma. Empirical work following this approach has helped establish the prevalence of cooperation based on reciprocity. Theoretical work has led to a deeper understanding of the role of other factors in the evolution of cooperation: the number of players, the range of possible choices, variation in the payoff structure, noise, the shadow of the future, population dynamics, and population structure.  相似文献   

Regulation of phosphodiesterase synthesis: requirement for cyclic adenosine monophosphate-dependent protein kinase   总被引：7，自引：0，他引：7  

H R Bourne  G M Tomkins  S Dion 《Science (New York, N.Y.)》1973,181(103):952-954

Endogenous cyclic adenosine monophosphate (AMP) and its dibutyryl derivative increase cyclic AMP phosphodiesterase activity in cultured lymphoma cells. This effect is prevented by cycloheximide. A variant population of cells deficient in cyclic AMP-dependent protein kinase contains lower basal phosphodiesterase activity, which cannot be induced by cyclic AMP.  相似文献   

Factors affecting mango (Mangifera indica L.) protoplast isolation and culture     

Ramezan Rezazadeh  Richard R. Williams  Dion K. Harrison 《Scientia Horticulturae》2011

The major factors influencing protoplast isolation and culture of mango (Mangifera indica L.) cv. Kensington Pride were investigated. The resultant protocol was used to compare plating efficiency among 4 mango cultivars. Most responses differed between proembryonic masses (PEMs) and leaf sources. Protoplast yields of 15.22 × 10⁶ g⁻¹ from PEMs and 8.68 × 10⁶ g⁻¹ from greenhouse-derived leaves were obtained in a solution of 0.7 M mannitol CPW plus 1.5% cellulase, 1% hemicellulase and 0.75% macerozyme for PEMs or 0.5 M mannitol CPW plus 1.5% cellulose, 1% hemicellulase and 1.5% macerozyme for leaves. Culture in Ca-alginate beads with initial plating densities (IPD) of 2.5 × 10⁴ Pp mL⁻¹ for PEMs and 2.5 × 10⁵ for leaves gave the highest plating efficiencies (FPE). For PEMs 1 mg L⁻¹ 2,4-d and 3.5 mg L⁻¹ kinetin gave an FPE of 2.85% whereas lower kinetin (2 mg L⁻¹) plus 0.5 mg L⁻¹ 6-BAP was most effective for leaves (FPE of 2.12%). Most protoplast mortality occurred during the first week of culture and was more severe in liquid culture. In Ca-alginate beads, protoplast survival at 14 days was higher for PEMs (30%) than leaf (21%) as was the frequency of cell division (17.6% compared to 13.6%). PEMs protoplasts continued development through embryogenesis to in vitro plantlet regeneration whereas leaf protoplasts underwent cell division up to 40-cell colonies but failed to proceed further. For PEMs, polyembryonic cvs. Kensington Pride and Keow Savoey produced higher FPE (1.95%) than monoembryonic cvs. Tommy Atkins and Keitt (1.75%). There was no effect of cultivar for leaf protoplasts.  相似文献   

Cyanophora paradoxa genome elucidates origin of photosynthesis in algae and plants     

Price DC  Chan CX  Yoon HS  Yang EC  Qiu H  Weber AP  Schwacke R  Gross J  Blouin NA  Lane C  Reyes-Prieto A  Durnford DG  Neilson JA  Lang BF  Burger G  Steiner JM  Löffelhardt W  Meuser JE  Posewitz MC  Ball S  Arias MC  Henrissat B  Coutinho PM  Rensing SA  Symeonidi A  Doddapaneni H  Green BR  Rajah VD  Boore J  Bhattacharya D 《Science (New York, N.Y.)》2012,335(6070):843-847

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Identification of fusarium head blight resistance related metabolites specific to doubled-haploid lines in barley     

Sivakumar K. Chamarthi  Kundan Kumar  Raghavendra Gunnaiah  Ajjamada C. Kushalappa  Yves Dion  Thin M. Choo 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(1):67-78

Fusarium head blight (FHB) and deoxynivalenol (DON) mycotoxin produced by Fusarium graminearum reduce barley yield and quality worldwide. Hundreds of quantitative trait loci (QTLs) have been identified in wheat and barley but their functions are largely unknown. Metabolic profiling was applied to better understand the mechanisms of resistance and to identify potential FHB resistance biomarker metabolites in barley. Four FHB resistant (H15-2, H148-3, H203-2 and H379-2) and one susceptible (H97-2), two-row, purple, doubled-haploid (DH) lines of barley were inoculated with either the pathogen or mock-solution. The disease severity quantified as the area under the disease progress curve (AUDPC) significantly varied between the resistant and susceptible genotypes, but not among the resistant genotypes. Neither the amount of DON nor the detoxified product, proportion of total DON, was significant among lines. The resistance related (RR, higher in abundance in resistant than in susceptible) metabolites varied in numbers and fold changes among the DH resistant lines. A total of 144 RR constitutive (RRC) and 167 RR induced (RRI) metabolites were selected, of which 39 and 37, respectively, were putatively identified. These RR metabolites mainly belonged to six chemical groups: phenylpropanoids, hydroxycinnamic acid amides, flavonoids, fatty acids, terpenoids, and alkaloids. The specific RR metabolites identified in each DH line, the possible mechanisms of resistance in each and their use as potential biomarkers are discussed.  相似文献   

Mycotic lymphadenitis in cattle and Swine   总被引：1，自引：1，他引：0  

Dion WM  Bundza A  Dukes TW 《The Canadian veterinary journal. La revue veterinaire canadienne》1987,28(1-2):57-60

Lymph nodes with granulomatous mycotic lesions from 100 cattle and 9 pigs were examined. More than 90% of cases of mycotic lymphadenitis in cattle occurred in the mesenteric nodes, whereas in swine lesions occurred at multiple sites. All observed mycotic infections were caused by zygomycetes. Histologically the granulomas were characterized by necrosis, mineralization, and fibrosis with infiltration of eosinophils, neutrophils, lymphocytes, and giant cells. Mucoraceous-type hyphae were identified in most of the lesions, and Absidia corymbifera, Rhizopus rhizopodiformis, and R. oryzae were isolated. Within the lesions, chlamydospores were produced by R. rhizopodiformis. Mycelia in a few lesions were suggestive of infections with fungi of the Mortierellaceae and Entomophthoraceae.  相似文献   

Differential metabolic response of barley genotypes,varying in resistance,to trichothecene‐producing and ‐nonproducing (tri5−) isolates of Fusarium graminearum     

G. K. Kumaraswamy  A. C. Kushalappa  T. M. Choo  Y. Dion  S. Rioux 《Plant pathology》2012,61(3):509-521

Resistance of barley to Fusarium graminearum was studied using a pair each of resistant and susceptible black and yellow barley lines. The spikelets were inoculated with a trichothecene‐producing isolate, a trichothecene‐nonproducing isolate (tri5^?), or a mock solution. Spikelets were collected 72 h after inoculation and metabolites were analysed using a LC‐hybrid MS system. Metabolite abundances were used to identify the constitutive (RRC) and induced resistance‐related metabolites (RRI). The pathogen virulence factor, DON, and its plant detoxification product, DON‐3‐O‐glucoside (D3G), were also identified and designated as resistance‐indicator (RI) metabolites. The RRC, RRI and RI metabolites were putatively identified. Jasmonic acid was significantly induced in barley following inoculation with a trichothecene‐producing isolate, but not with a tri5^? isolate. The former isolate reduced the induction of both the number and amount of RR metabolites. The metabolites cinnamic acid, sinapoyl alcohol, coniferin, catechin and naringin were identified only in response to the inoculation with a tri5^? mutant. The abundances of p‐coumaric acid, coniferaldehyde and sinapaldehyde increased more in response to the tri5^? mutant than to the trichothecene‐producing isolate. The total amount of DON synthesized and its conversion to D3G varied greatly between the resistant and susceptible black barley, but not in yellow barley. Interestingly, an increase in the amount of total DON produced was associated with a decrease in the conversion of DON to D3G. The roles of RRC, RRI and RI metabolites in plant defence and their further use as potential biomarkers in screening are discussed.  相似文献   

Bovine Mastitis due to Prototheca zopfi   总被引：1，自引：1，他引：0       下载免费PDF全文

W. M. Dion 《The Canadian veterinary journal. La revue veterinaire canadienne》1979,20(8):221-222

A report is given of a case of bovine mastitis caused by the alga Prototheca zopfi which was erroneously identified as the yeast Cryptococcus neoformans. The resistance of protothecal mastitis to treatment with antibiotics commonly used in veterinary practice is briefly discussed.  相似文献   

Genome-scale identification of nucleosome positions in S. cerevisiae     

Yuan GC  Liu YJ  Dion MF  Slack MD  Wu LF  Altschuler SJ  Rando OJ 《Science (New York, N.Y.)》2005,309(5734):626-630

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Evaluation of black spruce (Picea mariana) as a bioindicator of aluminum contamination     

M. Dion  S. Loranger  G. Kennedy  F. Courchesne  J. Zayed 《Water, air, and soil pollution》1993,71(1-2):29-41

The aim of this work is to evaluate black spruce (Picea mariana) as an indicator of environmental aluminum contamination. The territory studied extends to a radius of 100 km around the Alcan aluminum refinery in Jonquiere, Quebec, Canada. Samples of wood were taken from the trunks of trees at 26 sites at distances of 5, 10, 20, 30, 40, 50 and 100 km from the refinery. Five trees were sampled at each site. Each sample was cut into 25 pieces corresponding to 50 yr growth. These were analyzed for aluminum by neutron activation. Soil samples taken near the bases of the trees were also analyzed and significant variations in exchangeable aluminum were observed as a function of direction from the refinery and distance. The pH of organic and mineral horizons show no significant difference. Exchangeable aluminum increased with soil acidity. The most contaminated sites showed important correlations (r²=0.73) between exchangeable aluminum in soil and aluminum in bark. We observed greater aluminum concentrations in tree rings corresponding to the last 20 yr, especially at sites directly exposed to environmental contamination along prevailing winds. In conclusion, black spruce appears to be a better spatial than chronological indicator of aluminum contamination.  相似文献