Genetic studies with a phosphoglucose isomerase mutant of Saccharomyces cerevisiae.

Summary A mutation pgi1 in the yeast Saccharomyces cerevisiae conferring deficiency of the glycolytic enzyme glucose 6-phosphate isomerase is characterised genetically. The mutation segregates 2⁺:2^- in tetrads from diploids heterozygous for the mutant phenotype. The mutation is semi-dominant and is located on the right arm of chromosome II in the order: tsm134-lys2-pgi1-tyr1 approximately 15 map units from tyr1. The mutation pgi1 defines the structural gene of glucose 6-phosphate isomerase and can be suppressed intragenically giving revertants that have an unstable enzyme. In one temperature-sensitive revertant no enzyme activity in excess of the mutant level could be detected although fructose 6-phosphate was converted to glucose 6-phosphate in vivo. The suppressor locus in this revertant is dominant and is unlinked to the pgi1 locus.     

Revertants of a streptomycin-resistant, oligosporogenous mutant ofBacillus subtilis

Summary Revertants of a streptomycin-resistant (Str^R), oligosporogenous (Spo^-) mutant ofBacillus subtilis were selected for the ability to sporulate. The revertants obtained fell into two phenotypic classes: Str^S Spo⁺ (streptomycin-sensitive, sporeforming), which arose by reversion of the streptomycin resistance mutations of the parent strain; and Str^R Spo⁺, which arose by the acquisition of additional mutations, some of which were shown to affect ribosomal proteins. Alterations of ribosomal proteins S4 and S16 in the 30S subunit and L18 in the 50S subunit were detected in Str^R Spo⁺ revertants by polyacrylamide gel electrophoresis. Streptomycin resistance of the parental strain and the Str^R revertants was demonstrated to reside in the 30S ribosomal subunit. The second site mutations of the revertants depressed the level of streptomycin resistance in vivo and in the in vitro translation of phage SP01 messenger ribonucleic acid (mRNA) relative to the resistance exhibited by the Str^R parental strain. The Str^R parent grew slowly and sporulated at approximately 1% of the wild type level. The Str^S revertants closely resembled the wild type strain with regard to growth and sporulation. The Str^R revertants grew at rates intermediate between those of the Str^R parent and wild type, and sporulated at wild type levels.     

Reversion from Suppression to Nonsuppression in SUQ5 [psi+] Strains of Yeast: The Classification of Mutations

Reversion from the suppressed to nonsuppressed phenotype in strains of genotype SUQ5 [psi⁺] ade2-1 his5-2 lys1-1 can1-100 ura3-1 has been induced by treatment with ethyl methanesulphonate, nitrosoguanidine or UV (254 nm) light. Spontaneously occurring revertants have also been selected by two different methods. Reversion has been shown to occur through a variety of nuclear mutations and through mutation of [psi⁺] to [psi^-]. Nuclear mutations included back-mutation of SUQ5, antisuppressor mutations that were recessive, semi-dominant or dominant, and dominant or recessive mutations of genes required for the maintenance of the [psi⁺] factor. Complementation tests by which the various kinds of mutations could be distinguished from one another were designed. The spectra of spontaneously occurring and induced mutations have been described.     

Revertants from RNase III negative strains of Escherichia coli

Summary E. coli strains carrying the rnc-105 allele do not show any level of RNase III in extracts, grow slower than rnc ⁺ strains at temperatures up to 45°C and fail to grow at 45°C. Revertants which can grow at 45°C were isolated. The vast majority of them still do not grow as fast as rnc ⁺ strains and did not regain RNase III activity. The mutation(s) which caused them are suppressor mutations (physiological suppressors) which do not map in the immediate vicinity of the rnc gene. A few of the revertants regain normal growth, and contain normal levels of RNase III. They do not harbor the rnc-105 allele and therefore are considered to be true revertants. By using purines other than adenine it was possible to isolate rnc ⁺ pur ^- revertants from an rnc ^- pur ^- strain with relative ease. They behaved exactly like the true rnc ⁺ revertants isolated from rnc ^- strains at 45°C.A merodiploid strain which contains the rnc ⁺ gene on an episome behaves exactly like an rnc ⁺ strain with respect to growth and RNA metabolism, eventhough its specific RNase III activity is about 60% of that of an rnc ⁺ strain; thus the level of RNase III is not limiting in the cell.The rnc ^- strains show a characteristic pattern of transitory molecules, related to rRNA, 30S, 25S, p23 and 18S, which are not observed in rnc ⁺ strains. This pattern is unchanged in rnc ^- strains and in the revertants which are still lacking RNase III, regardless of the temperature in which RNA synthesis was examined (30° to 45°C). On the other hand, in the rnc ⁺ strains as well as in the true revertants and the rnc ⁺/rnc ^- merodiploid, the normal pattern of p16 and p23 is observed at all temperatures. These findings suggest that all the effects observed in RNase III^- strains are due to pleiotropic effects of the rnc-105 allele, and that the enzyme RNase III is not essential for the viability of the E. coli cell.     

Isolation and characterization of cold-sensitive mutations at the benA, beta-tubulin, locus of Aspergillus nidulans

Summary We have isolated large numbers of conditionally lethal -tubulin mutations to provide raw material for analyzing the structure and function of tubulin and of microtubules. We have isolated such mutations as intragenic suppressors of benA33, a heat-sensitive (hs^-) -tubulin mutation of Aspergillus nidulans. Among over 2,600 revertants isolated, 126 were cold-sensitive (cs^-). In 41 of 78 cs^- revertants analyzed, cold sensitivity and reversion from hs^- to hs⁺ were due to mutations linked to benA33. In three cases reversion was due to mutations closely linked to benA33 but cold sensitivity was due to a coincidental mutation unlinked to benA33. In the remaining 34 cases reversion was due to mutations unlinked to benA33. Thirty-three of the revertants in which cold sensitivity and reversion were linked to benA33 were sufficiently cold-sensitive to allow us to select for rare recombinants between benA33 and putative suppressors in a revertant x wild-type (wt) cross. We found only one recombinant among 1,000 or more viable progeny from crosses of each of these revertants with a wt strain. Reversion is thus due to a back mutation or very closely linked suppressor in each case. We have analyzed 17 of these 33 revertants with greater precision and have found that, in each case, reversion is due to a suppressor mutation that maps to the right of benA33. The recombination frequencies between benA33 and the suppressors are very low (less than 1.2×10^-4) in all cases. Five of these 33 revertants have been examined microscopically and in each of them nuclear division and nuclear migration are inhibited at a restrictive temperature. We conclude that at least some and perhaps all of these revertants carry intragenic suppressors of benA33 that, in combination with benA33, cause cold sensitivity by inhibiting the functioning of microtubules at low temperatures. Of the 17 suppressors mapped, 11 map to two clusters. These clusters are likely to define regions particularly important to the functioning of the -tubulin molecule.     

Cytochrome b of cob revertants in yeast. 1. Isolation and characterization of revertants derived from cob exon mutants of Saccharomyces cerevisiae

Summary About 300 revertants were derived from 44 cob ^- mutants, mapping in the structure coding regions (exon 1, 3, 4, 5, or 6) of the mitochondrial apocytochrome b gene in Saccharomyces cerevisiae, strain 777-3A. Most of the revertants could not be distinguished from the wild-type by means of physiological properties. Twenty-two revertants different in phenotype are described here in more detail.The suppressor mutations (sup ^a) that compensate the primary cob ^- mutations (i.e., restore growth on glycerol) are mitochondrially inherited. They were localized in the same cob exon regions as the respective primary mutations, except for one revertant with a primary mutation in exon 6 and a suppressor, 4.2 map units distant, which may be located either in intron 5 or downstream in exon 6.Of 21 suppressors 17 are closely coupled to the primary mutation with recombination frequencies of 0.1%–0.3%. An estimate predicts that in more than 80% of these revertants only one amino acid is altered at that point of the polypeptide corresponding to the cob ^- site in the gene.The most interesting revertant phenotypes are: (1) reduced growth rate on glycerol. The respective cob ^-/sup^a mutations are scattered over the whole cob region and cannot be correlated exclusively with special gene regions. (2) decreased cytochrome b content. The most extreme reductions (28% and 30% of wild-type level) were observed to be due to mutations located in the 5 proximal part of exon 1. The highest percentage of revertants with decreased cytochrome b content was predominantly found mapping in exon 3. Complications in protoporphyrin attachment or the chelatase reaction were assumed to be the basic lesion causing reduced cytochrome b content, since in 10 out of 11 revertants examined the polypeptide is produced at wild-type level. (3) shifted maximum absorption wavelength of cytochrome b. The double mutations of the respective revertants map in the middle part of exon 1, in exon 4 and exom 5. The corresponding regions in the polypeptide presumably surround the heme group.     

Reversal by DNA amplifications of an unusual mutation blocking alkane and alcohol utilization in Pseudomonas putida

Summary We analyzed the reversion of strains carrying alk208, a mutation in the alkBAC (alkane utilization) region of the Pseudomonas CAM-OCT plasmid. Reversion of alk208 was stimulated 25 to 75-fold by small doses of UV-irradiation. All alkane hydroxylase-positive (AlkB⁺) revertants proved to be aliphatic alcohol dehydrogenasepositive (AlkC⁺) as well, whereas AlkC⁺ revertants could be either AlkB⁺ or AlkB^-. Most of the AlkB^- AlkC⁺ partial revertants produced AlkC^- segregants at measurable frequencies. UV-irradiation substantially increased the rate of AlkC^- segregation. Most segregants reverted to AlkB⁺ or AlkC⁺ at frequencies similar to the original alk208 strain. Dot blot hybridization analyses using cloned probes from various regions of CAM-OCT revealed that the partial revertants contained specific amplications of alk DNA. The endpoints of these amplifications mapped in at least two regions. AlkC^- segregants had lost the DNA amplifications.     

Quantitative changes in tRNA during ethylene induced ripening (ageing) of tomato fruits

Iso-accepting forms of tRNA^met, tRNA^leu, tRNA^lys, and tRNA^tyr were isolated from combined walls and septa of tomato fruits at 5 consecutive stages of ethylene induced ripening. Changes in the relative amount of some tRNA^leu and tRNA^lys were discerned 10hr after exposure to ethylene. Individual patterns of change for each of several iso-acceptor tRNAs were evident throughout the ripening sequence. Maximal changes were: tRNA^lys, ?66.3%; tRNA^leu, ?24.8%; and tRNA^met, +26.7%.     

The exceptionally high rate of spontaneous mutations in the polymerase delta proofreading exonuclease-deficient Saccharomyces cerevisiae strain starved for adenine

Background

Mutagenesis induced in the yeast Saccharomyces cerevisiae by starvation for nutrilites is a well-documented phenomenon of an unknown mechanism. We have previously shown that the polymerase delta proofreading activity controls spontaneous mutagenesis in cells starved for histidine. To obtain further information, we compared the effect of adenine starvation on mutagenesis in wild-type cells and, in cells lacking the proofreading activity of polymerase delta (phenotype Exo^-, mutation pol3-01).

Results

Ade⁺ revertants accumulated at a very high rate on adenine-free plates so that their frequency on day 16 after plating was 1.5 × 10^-4 for wild-type and 1.0 × 10^-2 for the Exo^- strain. In the Exo^- strain, all revertants arising under adenine starvation are suppressors of the original mutation, most possessed additional nutritional requirements, and 50% of them were temperature sensitive.

Conclusions

Adenine starvation is highly mutagenic in yeast. The deficiency in the polymerase delta proofreading activity in strains with the pol3-01 mutation leads to a further 66-fold increase of the rate of mutations. Our data suggest that adenine starvation induces genome-wide hyper-mutagenesis in the Exo^- strain.     

Isolation and characterization of Hfr males in Citrobacter freundii

Citrobacter freundii Hfr donor strains were isolated from a C. freundii strain harbouring a temperature-sensitive factor F ts 114 lac ⁺, by selecting for integrative suppression of the ts 114 mutation. Three Hfr strains were characterized, which transfer their chromosomes in a linear and oriented order. The first strain transfers: O-aro ⁺-ilv ⁺-pur ⁺-thr ⁺-leu ⁺-pro ⁺, the second: O-ilv ⁺-pur ⁺-thr ⁺-leu ⁺-pro ⁺ and the third: O-ilv ⁺-aro ⁺-nad ⁺-his ⁺-pro ⁺. The whole chromosome is transferred into the recipient cell within about 145 minutes. From these results we concluded that the linkage map of C. freundii is circular. Mating-pair formation on a membrane filter resulted in more recombinants being formed as compared with mating-pair formation in liquid medium. Furthermore the mating-pairs formed on a membrane were more stable. From one Hfr strain heterogenic F-prime factors could be isolated bearing the F ts 114 lac ⁺ genes from Escherichia coli and the pur ⁺ and/or ilv ⁺ genes from C. freundii. Preliminary mapping by interrupted mating indicated that the linkage map of C. freundii is in general very similar to those of E. coli, Salmonella typhimurium and Klebsiella aerogenes.     

Analysis of merodiploids of the cysB region in Salmonella typhimurium.

Summary We have studied the regulation of two cysteine biosynthetic enzymes in S. typhimurium merodiploid strains which are heterozygous at the cysB regulatory locus. This gene codes for an element of positive control which is necessary for the expression of the enzymes of the biosynthetic pathway. Under conditions of sulfur deprivation levels of sulfite reductase (coded for by cysI, cysJ and cysG) and of O-acetylserine sulfhydrylase (coded for by cysK) are derepressed in cysB ⁺ haploid strains, but not in cysB ^- haploid strains. Growth on a rich sulfur source such as l-cystine results in low levels of both enzyme activities in cysB ⁺ and cysB ^- haploid strains but not in cysB ^c haploid strains, where enzyme expression is constitutive, i.e. substantially greater than in a cysB ⁺ strain grown on l-cystine, regardless of the nutrients used for growth.We find that cysB ^-/F cysB ⁺ merodiploid strains can be derepressed for sulfite reductase and O-acetylserine sulfhydrylase by growth on a poor sulfur source, and therefore cysB ⁺ is dominant to cysB ^-. Enzyme levels are also derepressed in l-cystine-grown cysB ^c/F cysB ⁺ strains indicating that cysB ^c is dominant to cysB ⁺. The cysB484 allele is known to be cysB ^- in regard to the regulation of sulfite reductase activity, but cysB ^c with respect to O-acetylserine sulfhydrylase. In a cysB484/F cysB ⁺ strain the cysB ^- character of cysB484 is recessive to cysB ⁺, while cysB ^c is dominant to cysB ⁺.Merodiploids of the type cysB ^-/F cysB ⁺, bearing chromosomal point mutations are derepressed by sulfur deprivation to levels which are either less than, equal to, or greater than those of wild type. These results can be explained by assuming a multimeric structure for the cysB protein and the formation in merodiploids of cysB ^-/cysB ⁺ hybrid molecules with altered capacities for gene activation. The dominance of cysB ^c over cysB ⁺ indicates that in contrast to the araC regulatory protein, which acts as both a gene activator and repressor, the cysB protein serves only as an element of positive control.     

Evidence for a relationship between malate metabolism and activity of 1-sinapoylglucose: L-malate sinapoyltransferase in radish (Raphanus sativus L.) cotyledons

The control of malate metabolism and stimulation of 1-sinapolyglucose: L-malate sinapoyltransferase (SMT) activity in radish (Raphanus sativus L. var. sativus) cotyledons has been studied. The light-induced and nitrate-dependent activity of SMT catalyzes the formation of O-sinapoly-L-malate via 1-O-sinapoyl--D-glucose. When dark-grown radish seedlings, cultivated in quartz sand with nutrient solution containing NO ₃ ^- as the sole N source, were treated with light, SMT activity increased concomitantly with free malate in the cotyledons. This light effect was suppressed in seedlings grown in a culture medium which contained in addition to NO ₃ ^- also NH ₄ ⁺ . However, treatment with methionine sulfoximine neutralized this ammonium effect, resulting again in both rapid accumulation of malate and rapid increase in SMT activity. When seedlings grown on NO ₃ ^- nitrogen were subsequently supplied with NH ₄ ⁺ nitrogen, the accumulated level of L-malate rapidly dropped and the SMT increase ceased. The enzyme activity decreased later on, reaching the low activity level of plants which were grown permanently on NO ₃ ^- /NH ₄ ⁺ -nitrogen. An external supply (vacuum infiltration) of malate to excised cotyledons and intact seedings, grown on NO ₃ ^- /NH ₄ ⁺ -nitrogen medium, specifically promoted a dose-dependent increase in the activity of SMT. In summary these results provide evidence indicating that the SMT activity in cotyledons of Raphanus sativus might be related to the metabolism of malic acid.Abbreviation MSO L-methionine sulfoximine - SinGlc 1-O-sinapoyl--D-glucose - SinMal O-sinapoyl-L-malate - SMT 1-O-sinapoyl--D-glucose:L-malate sinapolytransferase     

Peripheral Blood T Cell Dynamics Predict Relapse in Multiple Sclerosis Patients on Fingolimod

Background

Fingolimod efficiently reduces multiple sclerosis (MS) relapse by inhibiting lymphocyte egress from lymph nodes through down-modulation of sphingosine 1-phosphate (S1P) receptors. We aimed to clarify the alterations in peripheral blood T cell subsets associated with MS relapse on fingolimod.

Methods/Principal Findings

Blood samples successively collected from 23 relapsing-remitting MS patients before and during fingolimod therapy (0.5 mg/day) for 12 months and 18 healthy controls (HCs) were analysed for T cell subsets by flow cytometry. In MS patients, the percentages of central memory T (CCR7⁺CD45RO⁺) cells (TCM) and naïve T (CCR7⁺CD45RO^-) cells decreased significantly, while those of effector memory T (CCR7^-CD45RA^-) and suppressor precursor T (CD28^-) cells increased in both CD4⁺T and CD8⁺T cells from 2 weeks to 12 months during fingolimod therapy. The percentages of regulatory T (CD4⁺CD25^highCD127^low) cells in CD4⁺T cells and CCR7^-CD45RA⁺T cells in CD8⁺T cells also increased significantly. Eight relapsed patients demonstrated greater percentages of CD4⁺TCM than 15 non-relapsed patients at 3 and 6 months (p=0.0051 and p=0.0088, respectively). The IL17-, IL9-, and IL4-producing CD4⁺T cell percentages were significantly higher at pre-treatment in MS patients compared with HCs (p<0.01 for all), while the IL17-producing CD4⁺T cell percentages tended to show a transient increase at 2 weeks of fingolimod therapy (p^corr=0.0834).

Conclusions

The CD4⁺TCM percentages at 2 weeks to 12 months during fingolimod therapy are related to relapse.     

Analysis of a genetically unstable region inStreptomyces lividans 66-TK64

Genetic and molecular analyses of an unstable region encompassing the gene loci cml arg and a 5.7 kb amplifiable unit of DNA were done. Spontaneous mutants from Cm1^R →Cml^S and the revertants from Cml^S →Cml^R were analysed for mutations at arg locus and amplification of amplifiable unit of DNA. Twenty-one revertants were analysed. Two of these had large-scale amplification and one of these was also Arg^-. Nine of the revertants which were Arg⁺ had low-level or intermediate-level amplification of the 5.7 kb DNA sequence but no deletions of the flanking sequences were detected. Five of the CmI^R’ revertants, which were also Arg⁺, had lost one of the two copies from the doublet of amplifiable unit of DNA. The remaining five revertants did not show any other change. The amplifiable unit of DNA, therefore, not only undergoes amplification but can also suffer specific deletion of one copy. Thus, this region as a whole is characterized by instability and the events appear to take place at more than one locus concomitantly with a high frequency.     

Complementation studies with the repair-deficient uvrD3, uvrE156, and recL152 mutations in Escherichia coli

Summary Previous work showed that the mutations uvrD3, uvrE156, and recL152 were closely linked and increased UV-sensitivity. They were phenotypically distinguishable in that only the uvrD3 mutation significantly decreases host cell reactivation of UV-irradiated phage (Hcr^-) and repair of methylmethane sulfonate (MMS)-induced damage, and only the uvrE156 mutation increased mutation rates (Mut^-). MMS-resistant revertants of a uvrD3 mutant were still UV-sensitive and fell into two phenotypic classes, Hcr^- Mut⁺ (non-mutator) and Hcr⁺ Mut^-. In this work complementation tests were done by examining UV-and MMS-sensitivity and host cell reactivation in heterogenotes containing combinations of uvrD3, uvrE156, recL152, and the MMS-resistant mutations derived from uvrD3. The mutations could not complement each other in the repair of UV-damage, the one trait all had in common, indicating that they were in one gene. For the most part, the different mutations were able to complement each other in respect to traits in which one was deficient and the other had wild type activity.     

Insertion mutations in the control region of the Gal operon of E. coli. I. Biological characterization of the mutations

Summary Galactose negative mutations are described which reduce the maximum expression of all three gal genes about 100-fold. The residual enzyme synthesis is not or only slightly inducible.These pleiotropic mutations map in the control region of the gal operon. No recombination is observed between these mutations. All mutants revert spontaneously to a Gal⁺ phenotype. In some mutations wildtype-like as well as constitutive revertants are obtained. The frequency of reversion can be increased by nitrosoguanidine (NG) in all mutants. The revertants, induced by this mutagen, are of a constitutive type.     

Recombination between genes located on nonhomologous chromosomes in Saccharomyces cerevisiae

We constructed strains of Saccharomyces cerevisiae that contained two different mutant alleles of either the leu2 gene or the ura3 gene. These repeated genes were located on nonhomologous chromosomes; the two ura3^- alleles were located on chromosomes V and XII and the two leu2^- alleles were located on chromosomes III and XII. Genetic interactions between the two mutant copies of a gene were detected by the generation of either Leu⁺ or Ura⁺ revertants. Both spontaneous and ultraviolet irradiation-induced revertants were examined. By genetic and physical analysis, we have shown that Leu⁺ or Ura⁺ revertants can arise by a variety of different genetic interactions. The most common type of genetic interaction is the nonreciprocal transfer of information from one repeat to the other. We also detected reciprocal recombination between repeated genes, resulting in reciprocally translocated chromosomes.     

High frequency embryogenesis in immature zygotic embryos of sunflower

In the present investigation, nutritional requirements for induction of a high frequency of well formed somatic embryos (SEs) from zygotic embryos (ZEs) of sunflower were assessed. Variables like genotype, embryo size (0.5–10 mm), sucrose concentration (30–240 g l⁻¹), carbohydrate source (sucrose, glucose, maltose), agar strength (0.2–1.0%), basal media (MS, Gamborg, Nitsch, White), photoperiod (light/dark) and temperature (20–36°C) were tested. All these variables except photoperiod had significant effect on the frequency of embryogenesis. Highest frequency of embryogenesis was facilitated by Gamborg basal salt media, 120–210 g l⁻¹ sucrose, 0.8–1.0% agar, smaller sized embryos (0.5–2 mm) and incubation temperature of 28–32°C. In addition to these, growth regulator combinations (2,4-D, 2,4-D+kinetin, BA+NAA) in varying concentrations were tried. Media supplemented with 2,4-D promoted direct embryogenesis, BA+NAA facilitated formation of single/multiple shoots while there was no response on 2,4-D+kinetin supplemented media. Zygotic embryos with well differentiated embryos were transferred to growth regulator free half strength MS medium for whole plantlet development. This revised version was published online in June 2006 with corrections to the Cover Date.     

Gibberellins play a role in the interaction between imidazole fungicides and cytokinins in Araceae

Imidazole fungicides such as imazalil, prochloraz, and triflurnizole and the triazole growth retardant paclobutrazol promote the shoot-inducing effect of exogenous cytokinins in Araceae, such as Spathiphyllum floribundum Schott and Anthurium andreanum Schott. The mechanism of their action could partially be based on the inhibition of gibberellic acid (GA) biosynthesis, because administration of GA₃ inhibits the phenomenon completely in S. floribundum. Not only is the suppression of GA biosynthesis involved, but also the metabolism of endogenous cytokinins is significantly altered. Although the balance between isopentenyladenine, zeatin, dihydrozeatin, and their derivatives was shifted to distinguished directions by administration of BA and/or imazalil and/or GA₃, no correlation between these changes in metabolic pathways and the number of shoots could be found. The metabolism of BA was not significantly altered by adding imazalil to the micropropagation medium of S. floribundum.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - [9R-5P]DHZ 9--d-ribofuranosyl-dihydrozeatin-monophosphate - [9R-5P]iP 6-isopentenyl-9--d-ribofuranosyladenine-monophosphate - [9R-5P]Z 9--d-ribofuranosyl-zeatin-monophosphate - [9G]BA 6-benzyl-9--d-glucopyranosyladenine - [9G]DHZ 9--d-glucopyranosyl-dihydrozeatin - [9G]iP 6-isopentenyl-9--d-glucopyranosyladenine - [9G]Z 9--d-glucopyranosyl-zeatin - [9R]BA 6-benzyl-9--d-ribofuranosyladenine - [9R]DHZ 9--d-ribofuranosyl-dihydrozeatin - [9R]iP 6-isopentenyl-9--d-ribofuranosyladenine - [9R]Z 9--d-ribofuranosyl-zeatin - BA 6-benzyladenine - DHZ dihydrozeatin - ES⁺ LC-MS/MS HPLC coupled Electrospray Tandem Mass Spectrometry - f.m. fresh mass - mT 6-(3-hydroxybenzyl)adenine - IMA imazalil - iP isopentenyladenine - NAA 1-naphthalene acetic acid - NFT Nutrient Film Technique - (OG)[9R]DHZ O--glucopyranosyl-9--d-ribofuranosyl-dihydrozeatin - (OG)[9R]Z O--d-glucopyranosyl-9--d-ribofuranosyl-zeatin - (OG)DHZ O--d-glucopyranosyl-dihydrozeatin - (OG)Z O--d-glucopyranosyl-zeatin - PAR Photosynthetic Active Radiation - PBZ paclobutrazol - PRO prochloraz - TDZ thidiazuron - TRI triflurnizole - Z zeatin