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Notes: Extracts of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) shoots were purified by reversed and normal phase HPLC; gibberellin (GA)-like compounds detected by radioimmunoassay with antibodies against GA4 and the Tan-ginbozu dwarf rice micro-drop biossay were analyzed by GC-MS. Three major components were identified as GA4, GA7, and GA9 while smaller amounts of GA1, GA3 and putative GA9-glucosyl ester were also present.

Notes: Gibberellins GA1, GA8. GA19. GA29. GA20 and GA56 (2-epi-GA8). were identified by combined gas chromatography-mass spectrometry in root extracts of elongating Salix pentandra L. seedlings. The presence of GA8 was also demonstrated for the first time in S. pentandra shoots. The levels of GA1, GA8, GA19, GA20 in shoot tissue and in roots were estimated by selected ion monitoring. While the amounts of GA8 and GA19 were similar in both plant parts. the levels of the biologically active GA1 and its immediate precursor GA20. were found to be much lower in roots than in shoots.

Notes: This report succinctly summarizes a number of experiments in which human leucocytes were activated by the mitogen in the supernatant of cultured Mycoplasma arthritidis (MAS). Lymphocytes from a large number of donors were found to be reactive when the two parameters of lymphoproliferation and of production of gamma interferon were analysed. Lymphocytes of cord blood origin were also reactive in lymphoproliferation. Their interferon production was low, but this has been established previously for mitogens in general. During the course of the studies, different batches of MAS were tested, including most recently a purified preparation. All of these were active. Removal of accessory cells adherent to nylon wool column abolished MAS reactivity, whereas it has little effect on lymphoproliferation induced by phytohaemagglutinin (PHA). MAS reactivity was also strongly reduced when monoclonal anti-HLA-DR antibodies were added to the leucocyte cultures.

Notes: A potent mitogen for T lymphocytes of various species has recently been isolated from the supernatant of cultured Mycoplasma arthritidis organisms (MAS). In the mouse, reactivity to this mitogen has been observed to be controlled by the I-E subregion of the major histocompatibility complex. We have analysed the responses of spleen cells from several inbred rat strains covering practically all known haplotypes of the major histocompatibility complex of the rat (RT1). Unlike in the mouse, all of these responded well to MAS, except for the BN rat strain, which is a low responder to all T-cell mitogens, including phytohaemagglutinin and concanavalin A. This unresponsiveness, however, appeared to be unrelated to the RT1 haplotype, since LEW.1N rats carrying the same RT1u haplotype as BN animals responded well. Mice of the strain C57BL/6 are non-responders to MAS, but—as previously shown—their spleen cell responses can be reconstituted by the addition of 2-mercaptoethanol. No such reconstitution was observed for the low responsiveness of BN rat spleen cells. Stimulation with MAS induced high titres of interferon (presumably gamma interferon) in spleen cells from all rat strains tested. Spleen cells from BN rats produced lower interferon activities than those from other strains.

Notes: The application of gibberellin A4/7 (GA4/7) to the stem of previous-year (1-year-old) terminal shoots of Scots pine (Pinus sylvestris) seedlings has been observed to stimulate cambial growth locally, as well as at a distance in the distal current-year terminal shoot, but the distribution and metabolic fate of the applied GA4/7, as well as the pathway of endogenous GA biosynthesis in this species, has not been investigated. As a first step, we analysed for endogenous GAs and monitored the transport and metabolism of labelled GAs 4, 9 and 20. Endogenous GAs from the elongating current-year terminal shoot of 2-year-old seedlings were purified by column chromatography and high-performance liquid chromatography and analysed by combined gas chromatography-mass spectrometry (GC-MS). GAs 1, 3, 4, 9, 12 and 20 were identified in the stem, and GAs 1, 3 and 4 in the needles, by full-scan mass spectrometry (GAs 1, 3, 4, 9 and 12) or selected-ion monitoring (GA20) and Kovats retention index. Tritiated and deuterated GA4, GA9 or GA20 were applied around the circumference at the midpoint of the previous-year terminal shoot, and metabolites were extracted from the elongating current-year terminal shoot, the application point, and the 1-year-old needles and the cambial region above and below the application point. After purification, detection by liquid scintillation spectrometry and analysis by GC-MS, it was evident that, for each applied GA, unmetabolised [2H2]GA and [3H]radioactivity were present in every seedling part analysed. Most of the radioactivity was retained at the application point when [3H]GA9 and [3H]GA20 were applied, whereas the largest percentage of radioactivity derived from [3H]GA4 was recovered in the current-year terminal shoot. It was also found that [2H2]GA9 was converted to [2H2]GA20 and to both [2H2]GA4 and [2H2]GA1, [2H2]GA4 was metabolised to [2H2]GA1, and [2H2]GA20 was converted to [2H2]GA29. The data indicate that for Pinus sylvestris shoots (1) GAs applied laterally to the outside of the vascular system of previous-year shoots not only are absorbed and translocated extensively throughout the previous-year and current-year shoots, but also are readily metabolised, (2) the GA metabolic pathways found are closely related to the endogenous GAs identified, and (3) GA9 metabolism follows two distinctly different routes: in one, GA9 is converted to GA1 through GA4, and in the other it is converted to GA20, which is then metabolised to GA29. The results suggest that the late 13-hydroxylation pathway is an important route for GA biosynthesis in shoots of Pinus sylvestris, and that the stimulation of cambial growth in Scots pine by exogenous GA4/7 may be due to its conversion to GA1, rather than to it being active per se.

Notes: In the temperate-zone woody species Salix pentandra elongation growth is regulated by the photoperiod. Long days sustain active growth, whereas short days induce cessation of apical growth, which is a prerequisite for winter hardening. It is shown that this is correlated to quantitative changes in levels of endogenous GA19 GA20, and GA1. Within two short days the amount of the active GA1 and its immediate precursor GA20, decreased markedly in young leaves us well as in stem tissue. Also, the amount of GA19, declined, but the decrease was delayed relative to that of GA1 and GA20. The ability of S. pentandra seedlings to respond to exogenous GA19, decreased with increasing numbers of short days. Observations that support the hypothesis that the level of GA1 in S. pentandra is regulated by the photoperiod in a quantitative mode with conversion of GA19, to GA20, being one target for control.Different distribution of GAs in various plant parts was observed. The level of GA was higher in young leaves than in other plant parts, and the amount of GA19 was 5–10 times higher in stem tissue than in leaves and roots. The ratios of GA8 to GA1 and GA20, were higher in roots as compared with other parts, as rods contained very low levels of GA1 and GA20, but amounts of GA20 comparable with other parts.

Notes: By application of a recently developed method allowing analysis of gibberellins (GAs) in mg amounts of tissue, the effect of photoperiod on levels of GAs in shoot tips of individual seedlings of the woody species Salix pentandra was studied. In elongating long day-grown seedlings, maximum levels of GA1 were found 5–20 mm below the apex, approximately twice the levels in other segments. After exposure of plants to 5 or 15 short days, the levels of GA1 were about 50% lower within this specific region of the stem, as compared with seedlings grown under long days. Short day-induced cessation of shoot elongation also correlated with overall declines in the levels of GA53, GA19, GA20 and GA8, Within each photoperiodic treatment the levels of these GAs were generally relatively similar throughout the upper 35 mm of stems. No differences in internode lengths or in lengths of pith or epidermal cells were found in plants grown under long days compared with those exposed to 5 short days. In both cases, cells in mitosis were observed in the subapical stem tissues of shoot tips. After 15 short days, stem elongation was completed, and dividing cells were generally not found in the subapical part of the stem. However, short day exposure did not prevent elongation of internodes and cells differentiated before the treatment was started. Thus, the localised decrease in level of GA1 in shoot tips under short days precedes the morphological and anatomical changes connected with the short day-induced cessation of elongation growth. This supports the hypothesised role for GA1 in photoperiodic control of shoot elongation in S. pentandra.

Notes: Short photoperiod induces growth cessation in seedlings of Norway spruce (Picea abies (L.] Karst.). Application of different gibberellins (GAS) to seedlings growing under a short photoperiod show that GA9 and GA20 can not induce growth. In contrast application of GA, and GA4 induced shoot elongation. The results indicate that 3β-hydroxylation of GA9 to GA4 and of GA20 to GA1 is under photoperiodic control. To confirm that conclusion, both qualitative and quantitative analyses of endogenous GAs were performed. GA1, GA3, GA4, GA7, GA9, GA12, GA15, GA15, GA20, GA29, GA34 and GA51 were identified by combined gas chromatography-mass spectrometry in shoots of Norway spruce seedlings. The effect of photoperiod on GA levels was determined by using deuterated and 14C-labelled GAs as intermal standards. In short days, the amounts of GA9, GA4 and GA1 are less than in plants grown in continuous light. There is no significant difference in the amounts of GA3, GA12, and GA20 between the different photoperiods. The lack of accumulation of GA9 and GA20 under short days is discussed.