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71.
The site specificity of the apicomplexans Gregarina cuneata and Gregarina sleini , in larval Tenebrio molitor was investigated. Gregarina cuneata was found to inhabit the anteriormost region of the larval midgut, while G. steini was restricted to the posterior portion of the intestine. The site specificity of the pair was conserved in single and concurrent infections. Interspecific interactions do not seem to be presently responsible for the resource partitioning by the 2 gregarine species. Key words. Gregarina, site specificity, Tenebrio molitor. 相似文献
72.
VESSEY J KEVIN; RAPER C DAVID JR; HENRY LESLIE TOLLEY 《Journal of experimental botany》1990,41(12):1579-1584
Net uptake of by non-nodulated soybean plants [Glycme max(L ) Merr cv Ransom] growing in flowing hydroponicculture was measured daily during a 63 d period of reproductivedevelopment between the first florally inductive photopenodand late seed growth Removal of from a replenished solution containing 10 mol m was determined by ion chromatography Uptake of continued throughout reproductive development The net uptakerate of cycled between maxima and minima with a periodicity of oscillation of 3 to 7 d during the floralstage and about 6 d during the fruiting stage. Coupled withincreasing concentrations of carbon and C:N ratios in tissues,the oscillations in net uptake rates of are evidence that the demand for carbohydrate by reproductiveorgans is contingent on the availability of nitrogen in theshoot pool rather than that the demand for nitrogen followsthe flux of carbohydrate into reproductive tissues. Key words: Nitrate uptake rate, carbon-nitrogen partitioning, Glycme max (L ) Merrill 相似文献
73.
ROWLAND-BAMFORD AMANDA J; ALLEN L HARTWELL JR; BAKER JEFFREY T; BOOTE KEN J 《Journal of experimental botany》1990,41(12):1601-1608
The atmospheric carbon dioxide (CO2) concentration has beenrising and is predicted to reach double the present concentrationsometime during the next century. The objective of this investigationwas to determine the long-term effects of different CO2 concentrationson carbohydrate status and partitioning in rice (Oryza sativaL cv. IR-30). Rice plants were grown season-long in outdoor,naturally sunlit, environmentally controlled growth chamberswith CO2 concentrations of 160, 250, 330, 500, 660, and 900µmolCO2 mol1 air. In leaf blades, the priority between the partitioningof carbon into storage carbohydrates or into export changedwith developmental stage and CO2 concentration. During vegetativegrowth, leaf sucrose and starch concentrations increased withincreasing CO2 concentration but tended to level off above 500µmolmol1 CO2. Similarly, photosynthesis also increased withCO2 concentrations up to 500µmol mol1 and thenreached a plateau at higher concentrations. The ratio of starchto sucrose concentration was positively correlated with theCO2 concentration. At maturity, increasing CO2 concentrationresulted in an increase in total non-structural carbohydrate(TNC) concentration in leaf blades, leaf sheaths and culms.Carbohydrates that were stored in vegetative plant parts beforeheading made a smaller contribution to grain dry weight at CO2concentrations below 330µmol mol1 than for treatmentsat concentrations above ambient Increasing CO2 concentrationhad no effect on the carbohydrate concentration in the grainat maturity Key words: CO2 enrichment, starch, sucrose 相似文献
74.
A Dynamic Growth Model of Vegetative Soya Bean Plants: Model Structure and Behaviour under Varying Root Temperature and Nitrogen Concentration 总被引:1,自引:0,他引:1
LIM JUNE TAEG; WILKERSON GAIL G.; RAPER C. DAVID JR; GOLD HARVEY J. 《Journal of experimental botany》1990,41(2):229-241
A differential equation model of vegetative growth of the soyabean plant (Glycine max (L.) Merrill cv. Ransom)was developed to account for plant growth in a phytotron systemunder variation of root temperature and nitrogen concentrationin nutrient solution. The model was tested by comparing modeloutputs with data from four different experiments. Model predictionsagreed fairly well with measured plant performance over a widerange of root temperatures and over a range of nitrogen concentrationsin nutrient solution between 0.5 and 10.0 mmol in the phytotron environment. Sensitivity analyses revealedthat the model was most sensitive to changes in parameters relatingto carbohydrate concentration in the plant and nitrogen uptakerate. Key words: Glycine max (L.) Merrill, dry matter, nitrogen uptake, partitioning, photosynthesis, respiration, sensitivity analysis 相似文献
75.
An enzyme assay was developed to measure the initial and Mg2+CO2activated forms of Ribulose 1,5-bisphosphate Carboxylase/Oxygenase(Rubisco) in rose leaves. The assay was verified by co-extractionof the leaflets with partially purified spinach Rubisco andthrough correlation with net photosynthetic rates of individualleaflets (r2=0.7324). Changes in activities were measured asa function of depth of leaves in the canopy for two cultivarsof greenhouse hybrid tea roses. Initial Rubisco activity declinedwith increasing canopy depth for both cultivars. The activatedform of the enzyme, however, remained constant with canopy depthfor cv. Red Success; but increased with canopy depth, then declinedafter mid-canopy in the cv. Royalty. Rubisco activities werealso measured in the cv. Red Success grown in CO2 enriched environments(100 mm3 dm3) at three humidity levels. The activitieswere not significantly affected by humidity treatment. However,there was a trend for plants grown at lower humidity to havehigher activated activities. Key words: Humidity, Rubisco, Rosa ? hybrida, Royalty, Red Success 相似文献
76.
J White M Blackman J Bill J Kappler P Marrack D P Gold W Born 《Journal of immunology (Baltimore, Md. : 1950)》1989,143(6):1822-1825
Two variants of the AKR thymoma BW5147 have been isolated which can no longer express functional TCR alpha- and beta-chains. By generating hybridomas with these variant fusion lines, TCR of any normal T lymphocyte, including TCR-gamma/delta, can be studied at a clonal level, without interference of the BW5147-derived receptor chains. In this study one of the variants has been useful in identifying the reactivity to allogeneic MHC Ag of BW5147 itself. 相似文献
77.
Induction of anchorage-independent growth in human diploid fibroblasts by the cyclopenta-polycyclic aromatic hydrocarbon, benz[l]aceanthrylene 总被引:1,自引:0,他引:1
Cyclopenta-fused polycyclic aromatic hydrocarbons are a class of environmental PAH that have been recently identified. Many of these chemicals have been found to be more active than benzo[a]pyrene in tests for genetic toxicity using bacterial and rodent cells. Benz[l]aceanthrylene, a cyclopenta-polycyclic aromatic hydrocarbon related to benz[a]anthracene, and benzo[a]pyrene were compared for their activity to induce cytotoxicity and anchorage-independent growth with normal human diploid fibroblasts. Both benz[l]aceanthrylene and benzo[a]pyrene were relatively non-cytotoxic to normal human diploid fibroblasts. However, benz[l]aceanthrylene was twice as active compared to benzo[a]pyrene over the concentration range examined as an inducer of anchorage-independent growth. The ability of benz[l]aceanthrylene to induce anchorage-independent colony growth in normal human cells, in combination with its demonstrated ability as a mouse-skin tumorigen, suggests this PAH to be a potential multi-species carcinogen. 相似文献
78.
Degradation of azo dyes by the lignin-degrading fungus Phanerochaete chrysosporium. 总被引:8,自引:2,他引:6
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Under nitrogen-limiting, secondary metabolic conditions, the white rot basidiomycete Phanerochaete chrysosporium extensively mineralized the specifically 14C-ring-labeled azo dyes 4-phenylazophenol, 4-phenylazo-2-methoxyphenol, Disperse Yellow 3 [2-(4'-acetamidophenylazo)-4-methylphenol], 4-phenylazoaniline, N,N-dimethyl-4-phenylazoaniline, Disperse Orange 3 [4-(4'-nitrophenylazo)-aniline], and Solvent Yellow 14 (1-phenylazo-2-naphthol). Twelve days after addition to cultures, the dyes had been mineralized 23.1 to 48.1%. Aromatic rings with substituents such as hydroxyl, amino, acetamido, or nitro functions were mineralized to a greater extent than unsubstituted rings. Most of the dyes were degraded extensively only under nitrogen-limiting, ligninolytic conditions. However, 4-phenylazo-[U-14C]phenol and 4-phenylazo-[U-14C]2-methoxyphenol were mineralized to a lesser extent under nitrogen-sufficient, nonligninolytic conditions as well. These results suggest that P. chrysosporium has potential applications for the cleanup of textile mill effluents and for the bioremediation of dye-contaminated soil. 相似文献
79.
CARLOS ABEYTA JR. CHARLES A. KAYSNER JAN M. HUNT MARLEEN M. WEKELL 《Journal of Rapid Methods and Automation in Microbiology》1995,4(1):51-64
A method has been developed to detect thermophilic species of Campylobacter in shellfish, marine and tributary waters, sediment and farm runoff by-products such as manure and silage. The method consists of a 48 h enrichment incubation and subcultured to selective agars. Presumptive colonies confirmed with a latex agglutination (antibodies) to common flagellar antigens of C. jejuni, C. coli and C. lardi. Over an 8 year period, West Coast estuaries (Washington, Oregon, and California) were sampled, resulting in analysis of a total of 512 samples. Results suggest that Campylobacter spp. are well distributed in the marine environment. Two enrichment broths were compared for the recovery of campylobacters from environmental samples. The method described in the Food and Drug Administration Bacteriological Analytical Manual (FDA/BAM) (1984), was compared to a modified method. Use of the modified method described here resulted in higher recovery rates of Campylobacter spp. Recoveries of campylobacters from sediment, shellfish, and water were 10,13, and 28% higher for the modified method, respectively. 相似文献
80.
J. R. Gold T. L. King † L. R. Richardson D. A. Bohlmeyer G. C. Matlock † 《Journal of fish biology》1994,44(4):567-590
Nine polymorphic nuclear-gene (allozyme) loci were surveyed among 491 red drum ( Sciaenops ocellatus ) sampled in 1988 and 1989 from nearshore localities in the northern Gulf of Mexico (Gulf) and the Atlantic coast of the southeastern United States (Atlantic). Data were combined with those from a previous study to generate a data set of 762 individuals representing 11 sample localities in the Gulf and 175 individuals representing five sample localities in the Atlantic. The combined data set included individuals from the 1986 and 1987 year classes and permitted rigorous testing of both temporal and spatial genetic heterogeneity. Average heterozygosity-per-locus values (estimated using 33 assumed monomorphic loci) were 0·048 (Gulf red drum) and 0·046 (Atlantic red drum). Tests of heterogeneity in allele frequencies between year classes at individual localities and across regions (Gulf and Atlantic) were non-significant. Tests of spatial (geographic) heterogeneity indicated that red drum are weakly subdivided: genetically-differentiated subpopulations occur in the northern Gulf and along the south-eastern Atlantic coast. Genetic data were consistent with the hypothesis that red drum within the Gulf and along the Atlantic coast comprise singie subpopulalions. Genetic differences between Gulf and Atlantic red drum seem likeiy to stem from historical or recent interactions between dispersal and impediments to gene flow. 相似文献