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- Lindberg, A Michael, et al.
(författare)
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Genome of Coxsackievirus B3
- 1987
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Ingår i: Virology. - : Elsevier BV. - 0042-6822 .- 1096-0341. ; 156:1, s. 50-63
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Tidskriftsartikel (refereegranskat)abstract
- The entire nucleotide sequence of the coxsackievirus B3 strain Nancy (CB3) genome has been determined from cDNA. The genome is 7396 nucleotides long, and encodes a 2185 amino acid long polyprotein. It exhibits the same gene organization as other enterovirus genomes. A detailed comparison was carried out between the proteins encoded by the CB3 and poliovirus type 1 strain Mahoney (PVI) genomes. The genes encoding the VPg polypeptide and the viral polymerase are the most conserved regions. The structural polypeptides VP1, VP2, and VP3 are less well conserved although proline and tryptophan residues frequently are found in identical positions. The VP1 protein of CB3 shows a particularly limited homology in those regions which have been found to induce neutralizing antibodies against PV1. The 5′ noncoding region of CB3 is closely related to that of PV1, with regard to both length and sequence organization, whereas the 3′ noncoding region of CB3 exhibits some unique features.
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| 4. |
- Andersson, Agneta, et al.
(författare)
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Release of aminoacids and inorganic nutrients by heterotrophic marine microflagellates
- 1985
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Ingår i: Marine Ecology Progress Series. - 0171-8630 .- 1616-1599. ; 23, s. 99-106
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Tidskriftsartikel (refereegranskat)abstract
- Heterotrophic microflagellates isolated from the Baltic Sea and grown under laboratoryconditions were shown to release dissolved free amino acids (DFAA) when grazing bacteria. Flagellatesreleased 3H-amino acids when fed 3H-leucine-labelled bacteria, and concentrations of aminoacids increased in the experimental medium. Serine showed a strong positive correlation withflagellate feeding. Aspartic acid, glutamic acid and ornithine also increased more than other aminoacids. During consumption of bacteria, the flagellates released 13% of the ingested nitrogen asammonia, and 30 % of the ingested phosphorus as phosphate. In a field experiment off Scripps Pier, wemeasured bacterial production, flagellate abundance, and concentration of DFAA over a 28 h period.The concentration of DFAA showed a covariation with the flagellate numbers. Results from our fieldand laboratory experiments suggest that flagellates may be a source of DFAA in the sea.
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| 6. |
- Dahlbäck, B., et al.
(författare)
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Mikrobiologiska aspekter på musselodling
- 1983
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Ingår i: Odling av blåmusslor. - Lund : Signum. - 918533054X ; , s. 60-67
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Fuhrman, J.A., et al.
(författare)
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Diel variations in bacterioplankton, phytoplankton, and related parameters in the Southern California Bight.
- 1985
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Ingår i: Marine Ecology Progress Series. - 0171-8630 .- 1616-1599. ; 27, s. 9-20
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Tidskriftsartikel (refereegranskat)abstract
- The principal objectives of this study were (i) to determine the extent of coupling betweenphytoplankton and microheterotrophs on the shelf off Southern California. (ii) to compare differentmeasures of primary and bacterial secondary production, and (iii) to assess whether sampling timesshould be as strictly controlled for microheterotroph as for autotroph studies. Two diel cycles (May andOctober) were studied by sampling an isotherm as the ship followed paired submerged drogues. Wefound significant die1 changes of chlorophyll, 14C bicarbonate incorporation, bacterial abundance andthymidine incorporation, frequency of dividing bacterial cells (FDC), abundance of non-pigmentedflagellates, particulate organic carbon and nitrogen and their ratios, and dissolved oxygen. Theseparameters all had higher values dunng daylight hours than at night, showing close coupling betweenthe phytoplankton (light-forced) and the microheterotrophs. The ratio of in vivo to extractedchlorophyll a fluorescence, however, displayed a maximum at midnight and minimum at midday,suggesting an endogenous rhythm. Primary production measured by the 14C method was similar to netproduction inferred from in situ oxygen changes. Short-lived peaks in FDC values suggested partlysynchronized bacterial division.
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| 8. |
- Fuhrman, J.A., et al.
(författare)
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Extraction from natural planktonic microorganisms of DNA suitable for molecular biological studies
- 1988
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 54:6, s. 1426-1429
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Tidskriftsartikel (refereegranskat)abstract
- We developed a simple technique for the high-yield extraction of purified DNA from mixed populations ofnatural planktonic marine microbes (primarily bacteria). This is a necessary step for several molecularbiological approaches to the study of microbial communities in nature. The microorganisms from near-shoremarine and brackish water samples, ranging in volume from 8 to 40 liters, were collected on 0.22-,um-pore-sizefluorocarbon-based filters, after prefiltration through glass fiber filters, to remove most of the eucaryotes. DNAwas extracted directly from the filters in 1% sodium dodecyl sulfate that was heated to 95 to 100°C for 1.5 to2 min. This procedure lysed essentially all the bacteria and did not significantly denature the DNA. The DNAwas purified by phenol extraction, and precautions were taken to minimize shearing. Agarose gel electrophoresisshowed that most of the final preparation had a large molecular size (>23 kilobase pairs). The DNA wassufficiently pure to allow complete digestion by the restriction endonuclease Sau3AI and ligation to vector DNA.In a sample in which the extracted DNA was quantified by binding to the dye Hoechst H33258, DNA wasquantitatively extracted, and 45% of the initially extracted DNA was recovered after purification. Final yieldswere a few micrograms of DNA per liter of seawater and were roughly 25 to 50% of the total bacterial DNAin the sample. Alternatives to the initial harvest by filtration method, including continuous-flow centrifugationand thin-channel or hollow-fiber concentration followed by centrifugation, were less efficient than filtration interms of both time and yield, largely because of the difficulty of centrifuging the very small bacteria typical ofmarine plankton. These methods were judged to be less appropriate for studies of natural populations as theyimpose a strong selection for the larger bacteria.
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