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71.
A. T. JONES 《The Annals of applied biology》1991,118(2):331-338
After graft inoculation with rubus yellow net virus (RYNV), 12 of 34 Rubus species and cultivars developed noticeable symptoms. R. macraei developed the most conspicuous symptoms and is recommended as an improved indicator plant. In attempts to determine the cause of raspberry veinbanding mosaic, a disease in which RYNV is involved, several European and North American red raspberry cvs were graft-inoculated with RYNV and three other aphid-borne viruses, black raspberry necrosis (BRNV), raspberry leaf mottle (RLMV) and raspberry leaf spot, singly and in all combinations. In periods of up to 4 yr, classical veinbanding mosaic symptoms developed in sensitive cvs only when they contained both RYNV and RLMV. These symptoms were intensified in plants co-infected with additional viruses. Veinbanding mosaic disease did not develop in any of 11 cvs infected with RYNV + BRNV, the combination of viruses previously assumed to be responsible for this disease in Britain and North America. 相似文献
72.
L. P. M. J. Wetsteyn J. C. H. Peeters R. N. M. Duin F. Vegter P. R. M. de Visscher 《Hydrobiologia》1990,195(1):163-177
Phytoplankton primary production, nutrient concentrations and turbidity were monitored at three stations in the Oosterschelde during 1980–1984 as part of an ecosystem study.From comparisons of dissolved nutrient ratios with the nutrient requirements of phytoplankton, and of ambient nutrient concentrations with half-saturation constants for nutrient uptake by natural phytoplankton populations it was concluded that silicate was a limiting nutrient for diatoms after the spring bloom until the end of the summer. Dissolved inorganic nitrogen and phosphate were not considered to be limiting to phytoplankton growth.In general, the phytoplankton growing season started during the first fortnight of April and ended at the end of September. Column production in the whole Oosterschelde varied between 201 and 540 g C m–2 yr–1 and was, on average, 25% higher in the western part than in the eastern part. Basin production in the Oosterschelde varied between 120 and 466 g C m–2 yr–1 and was, on average, 55% higher in the western part than in the eastern part; this difference could be explained by differences in the ratio of euphotic depth to mean depth of the compartments.Estimated carbon-specific growth rates in the eastern part varied between < 0.1 and 3 d–1 and in the western part between < 0.1 and 1 d–1. This difference could be explained by the great differences in depth of the compartments. Carbon-specific growth rates are discussed in relation to phytoplankton loss rates. It is suggested that in the eastern part sedimentation must be an important sink for phytoplankton.Communication no. 473 of the Delta Institute for Hydrobiological Research, Yerseke, The Netherlands. 相似文献
73.
74.
Size-frequency estimates of secondary production byMysis relicta in Lakes Michigan and Huron 总被引:2,自引:2,他引:0
Daniel W. Sell 《Hydrobiologia》1982,93(1-2):69-78
Data from five Great Lakes studies ofMysis relicta populations were reanalyzed to calculate secondary production estimates using the size-frequency method. Production estimates (P) ranged from 0.25 to 3.2 g dry weight m–2 yr–1. Average annual biomass {xxB} and mean annual density (xxD) were 0.11–1.11 g dry weight/ m2 and 25–434 animals/ m2, respectively. P:{xxB} ratios varied only between 2.2 and 3.3. Maximum and minimum biomass values within a study varied by a factor of 519 for one study but by less than 17 for the others. Highest estimates of P, {xxB} and {xxD} were calculated for collections from a 50-m station in Lake Michigan despite the larger populations suspected to be present at greater depths sampled in the other studies. These conservative estimates provide a basis for scaling trophic interactions involvingM. relicta and emphasize findings by previous workers that night-time sampling with vertical net hauls is the best available technique for quantitative studies ofM. relicta populations in the Great Lakes. 相似文献
75.
Carol J. Maslansky Gary M. Williams 《In vitro cellular & developmental biology. Plant》1982,18(8):683-693
Summary Hepatocyte primary cultures (HPC) derived from rat, mouse, hamster, and rabbit liver were characterized for a variety of parameters.
The conditions that maximized recovery, attachment, and survival varied between species. Hepatocytes from all four species
were capable of attaching in serum-free Williams’ medium E (WME), but optimal attachment as monolayer cultures was achieved
for mouse and hamster HPC in medium receiving 1% calf serum supplementation. Hamster hepatocytes required additional cations,
whereas rabbit and rat hepatocytes displayed maximal attachment in medium supplemented with 10% calf serum. Survival of mouse
and rabbit hepatocytes after 24 h in serum supplemented media was in the order of 90%. Rat and hamster hepatocyte 24 h survival
was approximately 70 and 60%, respectively, and was not significantly affected by serum supplementation. Hepatocytes from
each species varied in their content of cytochromeP450 at the time of isolation and in the rate of reduction during culture. Mouse and rat hepatocytes demonstrated the most
rapid decline in content during the initial 24 h in culture, whereas concentrations in rabbit hepatocytes were virtually unchanged.
The rate of decline inP450 concentrations in hamster hepatocytes was intermediate between those displayed by rat and rabbit hepatocytes. These studies
have delineated conditions useful for the culture of hepatocytes from four species and have documented the status of an important
parameter of their functional capability.
This study was supported by EPA contract 68-01-6179. C. J. Maslansky was a recipient of a Monsanto Fund Fellowship in Toxicology. 相似文献
76.
A comparison is made between the flavone patterns accumulating in epidermal tissues and in the mesophyll of oat primary leaves grown in a phytotron and under field conditions. In developing leaves cultivated under standard conditions, varying patterns of two vitexin-derived O-rhamnosides and of one isovitexin O-arabinoside are produced in the basal region as the result of basal meristem activity. These patterns are tissue specific and differ quantitatively in the epidermis and the mesophyll. During the course of subsequent growth and differentiation, this pattern is constant as the compounds are moved upwards due to basipetal leaf growth. In comparison, the flavone patterns generated in the basal section of leaves grown in the field do not vary significantly. There is the additional accumulation of isoorientin O-arabinoside. Again flavone patterns are tissue specific, but in contrast to standard growth they are modified characteristically in those leaf tissues which are already morphologically differentiated. It is possible that the isovitexin moiety of the O-arabinoside is oxidized to the corresponding isoorientin derivative in the mesophyll. Moreover, field-grown leaves show a two-fold increase in flavone content in each leaf epidermis and a six-fold increase in the mesophyll when compared to the corresponding tissues of phytotron-grown leaves. 相似文献
77.
S. A. Weiss T. L. Lester S. S. Kalter R. L. Heberling 《In vitro cellular & developmental biology. Plant》1980,16(7):616-628
Summary Chemically defined media SFRE-199-1 for the growth and SFRE-199-2 for the maintenance of primary baboon kidney (Bak) cell
cultures were formulated by supplementing medium M199 with insulin, sodium pyruvate, zinc sulfate, and increasing arginine-HCl,
cysteine, cystine,l-glutamine,l-glutamic acid, glycine, histidine, tyrosine, and glucose to maximally active nontoxic concentrations. For prolonged maintenance
of the cells, physiological pH control, and blocking of excessive lactic acid accumulation in the spent medium of the cell
cultures, it was necessary to supplement the medium containing Earle's balanced salts withd-(+) galactose.
The cells grew and were maintained equally well on glass or polystyrene surfaces. Selenium, when added to growth medium or
substituted for insulin and zinc sulfate, did not stimulate cell growth. Electron microscopy showed that numerous dense particles,
approximately 250 to 400 ? in diameter, with the appearance of glycogen, were found throughout the cytoplasm in the cells
grown in SFRE-199-1 and maintained in SFRE-199-2. Echovirus types 1 to 3, poliovirus types 1 to 3, coxsackievirus types B2,
B4, B5,Herpesvirus hominis type 1, simian herpesvirusH. simiae and SA8, and simian adenovirus SV34 when titrated in primary Bak cells and grown and maintained in SFRE-199-1 and 2, respectively,
developed titers comparable to those obtained in conventionally grown and maintained cells.
This study was supported in part by National Institute of Health Grant RR00361 and World Health Organization Grant V4/181/38.
This laboratory serves as the NIH/WHO Collaborating Center for Reference and Research in Simian Viruses. 相似文献
78.
Bombesin production by human small cell carcinoma of the lung 总被引:5,自引:0,他引:5
G D Sorenson S R Bloom M A Ghatei S A Del Prete C C Cate O S Pettengill 《Regulatory peptides》1982,4(2):59-66
A series of continuous cell lines of human small cell carcinoma of the lung (SCCL) have been evaluated for the production of bombesin (BN). In early established cultures BN was detected in the medium of 9 out of 11 cell lines and in 6 out of 7 cell homogenates examined. Levels in the medium were frequently higher in cultures of later passages compared to earlier passages of the same line and low levels developed in the two previously negative cell lines. Plasma concentrations were greater than 80 pmol/l in 2 out of 27 (7%) randomly selected patients with SCCL. A culture (DMS 406) established from the tumor of a patient with the highest plasma level (1240 pmol/l) was the highest producer in vitro. The results indicate that BN, which has been demonstrated immunocytochemically to be present in normal bronchial mucosal cells, is frequently produced by SCCL in vitro but elevated plasma levels are infrequently found in patients with this neoplasm. 相似文献
79.
John M. Olson 《BBA》1981,637(1):185-188
Two reaction center complexes prepared from cytoplasmic membranes of Chlorobium limicola f. thiosulfato-philum were compared by absorption and CD spectrophotometry. Bacteriopheophytin c (670 nm), which is optically active in one complex but not in the other, may serve as a secondary electron acceptor in the reaction center. 相似文献
80.
Richard H. Monheimer 《Hydrobiologia》1981,79(2):121-127
Analyses of four years of in situ sulfate uptake by microplankton communities in two,trophically different lakes showed that about 12% of the experiments had dark uptake equal to or higher than uptake at ambient light. Three axenic algal cultures subjected to different light intensities showed that sulfate uptake patterns, relative to primary productivity, vary with species and although sulfate uptake tends to decrease at lower light levels, at or very near darkness, in physiologically active (young) cultures sulfate uptake frequently increases dramatically. The field data, when summarized according to the light received, shows the same trends seen in the axenic cultures. It is concluded that sulfate uptake is only loosely associated with inorganic carbon uptake (primary productivity) and that under some circumstances a low level of light may increase the sulfate uptake rate. 相似文献