| 1. |
|
|
| 2. |
|
|
| 3. |
- Bengtsson, M., et al.
(författare)
-
Plant odor analysis of apple : Antennal response of codling moth females to apple volatiles during phenological development
- 2001
-
Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 49:8, s. 3736-3741
-
Tidskriftsartikel (refereegranskat)abstract
- Volatile compounds were collected from apple branches (Malus domestica) at different developmental stages, and the antennal response of codling moth females (Cydia pomonella) to these compounds was recorded by electroantennography coupled to gas chromatography. Presence of a range of terpenoid compounds, many of which had antennal activity, was characteristic for volatile collections from branches with leaves, and from small green apples. Nine compounds from branches with leaves and green fruit consistently elicited an antennal response: methyl salicylate, (E)-beta -farnesene, fi-caryophyllene, 4,8-dimethyl-1,3(E),7-nonatriene, (Z)3-hexenol, (Z,E)-alpha -farnesene, linalool, germacrene D, and (EE)-alpha -farnesene. The bouquet emitted from flowering branches contained in addition several benzenoid compounds which were not found after bloom. Small green apples, which are the main target of codling moth oviposition during the first seasonal flight period, released very few esters. In comparison, fully grown apples released a large number of esters, but fewer terpenoids. The study of apple volatiles eliciting an antennal response, together with a survey of the seasonal change in the release of these compounds, is the first step toward the identification of volatiles mediating host-finding and oviposition in codling moth females.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Godhe, Anna, et al.
(författare)
-
PCR amplification of microalgal DNA for sequencing and species identification : studies on fixatives and algal growth stages
- 2002
-
Ingår i: Harmful Algae. - 1568-9883 .- 1878-1470. ; 1:4, s. 375-382
-
Tidskriftsartikel (refereegranskat)abstract
- Cultured strains and individually isolated dinoflagellate cells from field samples were preserved in different fixatives to find a method of cell preservation that could provide DNA template in PCR reactions and preserve cell morphology for microscopic studies. Lugol’s solution and various ethanol concentrations all showed shortcomings, whereas an initial formalin preservation step followed by storage in 100% methanol fulfilled both demands. Cells could be stored up to 1 year and still provide functional DNA template for positive PCR reactions. The amplified fragment was approximately 700 bp of the D1/D2 region of the LSU rDNA, which is to our knowledge significantly longer than the low-molecular-weight DNA typically reported from formalin preserved samples. By cloning and sequencing the PCR product and subsequently aligning the sequences with previously sequenced fragments of the same or similar species, we confirmed that no base pair alteration had taken place during the time that the cells were fixed and frozen. In another experiment it was demonstrated that the growth phase of cultured Alexandrium minutum did not have any influence on the result of PCR reactions. This was true for extracted DNA from cultures and for direct PCR with a small number of disrupted cells. Phenol/chlorophorm/isoamylalcohol extraction proved to be an unpredictable method for DNA extraction, whereas direct PCR on isolated cells was more reliable. Extracted DNA purified with a commercial DNA cleaning kit always rendered a positive PCR. The environmental condition for cells to be used as DNA template in PCR is discussed.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Rehnstam-Holm, Ann-Sofi, 1959, et al.
(författare)
-
Molecular studies of Dinophysis (Dinophyceae) species from Sweden and North America
- 2002
-
Ingår i: Phycologia. - 0031-8884. ; 41:4, s. 348-357
-
Tidskriftsartikel (refereegranskat)abstract
- Diarrhoeic, shellfish poisoning has increasingly become 4 Problem throughout the world. Because the causative organisms Dinophysis spp. cannot be cultured in the laboratory, new approaches are needed to obtain ecological and physiological information. In this study, a acuminata, D. norvegica and D, acuta were collected directly from field samples and used in polymerase chain reactions. The D1-D2 region of the large-subunit ribosomal RNA gene was amplified, cloned and sequenced. Sequence analyses showed that D. acuminata and D, norvegica were nearly identical (> 99%), and that D. acuminata showed an intraspecies variation of 0.8% The D. acuta sequence was 98.7% similar to that of D. acuminata. The slight differences between D. norvegica and D. acuminata suggest that they may have evolved into separate species rather recently. Phylogenetic analyses show that species within the Dinophysiales order should be included in the 'GPP complex', a lineage associated with a diverse array of taxa within the orders Gymnodiniales, Prorocentrales and Peridiniales. The Prorocentrales and Dinophysiales would be sister groups within the GPP complex. Amplification of Swedish D, acuminata isolates always resulted in a single LSU rDNA fragment. In contrast, amplification of the North American D. acuminata always produced two distinct fragments, The longer (735 bp) fragment showed 99.3-100% homology among all sequenced clones of different D. acuminata field isolates. The shorter gene fragment had a 70 bp deletion, but it was otherwise highly homologous to the larger gene fragment, This fragment is possibly a pseudogene and might be an important genetic marker. A variable region that is suitable as a target for a probe to identify, Dinophysis was also identified, Dinopkysis g specificity was confirmed for the probe, in that hybridization to cultured representatives of dinoflagellates and environmental samples containing mixed phytoplankton assemblages resulted in specific labelling of D. acuminata, D. norvegica and D, acuta, but not other dinoflaggellates, No labelling of D. rotundata was observed.
|
|
| 10. |
|
|
