Prolyl oligopeptidase participates in cell cycle progression in a human neuroblastoma cell line

Prolyl oligopeptidase (POP) is a post-proline cleaving enzyme, which is widely distributed in various organs, with high levels in the brain. In this study, we investigated the effects of a selective POP inhibitor, 3-({4-[2-(E)-styrylphenoxy]butanoyl}-l-4-hydroxyprolyl)-thiazolidine (SUAM-14746), on the growth of NB-1 human neuroblastoma cells. SUAM-14746 treatment for 24–72 h suppresses the growth of NB-1 cells without cell death in a dose-dependent manner (10–60 μM). Similar suppressive effects were observed with another POP inhibitor benzyloxycarbonyl-thioprolyl-thioprolinal. The SUAM-14746-induced growth inhibition in NB-1 cells was associated with pronounced G₀/G₁ arrest and reduced levels of phosphorylated retinoblastoma protein (pRb), cyclin E, and cyclin dependent kinase (CDK) 2, and increased levels of the CDK inhibitor p27^kip1 and the tumor suppressor p53. SUAM-14746 also induced transient inhibition of S and G₂/M phase progression, which was correlated with retardation of the decrease in the levels of cyclins A and B. Moreover, RNAi-mediated knockdown of POP also led to inhibition of NB-1 cell growth and the effect was accompanied by G₀/G₁ arrest. These results indicate that POP is a part of the machinery that controls the cell cycle.     

In vitro organogenesis and plant formation in cucumber

In vitro organogenesis was achieved from callus derived from hypocotyl explants of Cucumis sativus L. cv. Poinsett 76. Calli were induced from hypocotyl explants excised from 7-d-old seedlings grown on Murashige and Skoog (MS) medium containing 87.64 μM sucrose, 0.8 % agar, 3.62 μM 2,4-dichlorophenoxy acetic acid and 2.22 μM 6-benzyladenine (BA). Regeneration of adventitious buds from callus (25 shoots explant⁻¹) was achieved on MS medium supplemented with 8.88 μM BA, 2.5 μM zeatin and 10 % coconut water after two subcultures in the same medium at 30-d interval. Gibberellic acid (1.75 μM) favoured shoot elongation and indole 3-butyric acid (7.36 μM) induced rooting. Rooted plants were hardened and successfully established in soil.     

Intact rat superior mesenteric artery endothelium is an electrical syncytium and expresses strong inward rectifier K+ conductance

Background and purpose

Vascular endothelial and smooth muscle cell phenotypes may change dramatically after isolation and in cell cultures. This study was designed to investigate gap junctions coupling in an integrated intact preparation and to test if K_IR channels modulate resting membrane conductance in “in situ” endothelial cells (EC), and acetylcholine (ACh)-evoked relaxation of the rat superior mesenteric artery.

Experimental approach

Whole cell blind patch recordings of ionic currents from in situ EC, dye-coupling experiments, and functional studies were performed in rat superior mesenteric artery.

Key results

EC were dye-coupled through gap junctions. 18β-glycyrretinic acid (25 μM) decreased outward and inward currents, the 80% decay of time and time constant of the capacitative transients, capacitance, and increased input resistance. Barium chloride (30 μM) decreased resting and ACh-evoked inward currents, the sensitivity of ACh-evoked relaxation, and decreased both the sensitivity and the maximal relaxation to S-nitroso-N-acetyl penicillamine in arteries with, but not in arteries without endothelium.

Conclusions

The present results suggest that the EC layer of this large artery is electrically coupled, and that K_IR channels regulate resting inward conductance, hence suggesting that they are of importance for resting membrane potential in in situ EC. Moreover, EC K_IR channels are involved in ACh-evoked relaxation.     

Induction and characterization of in vitro corms of diploid-taro

When in vitro plantlets were cultured in Murashige and Skoog liquid medium supplemented with 8–10% sucrose and 22–44 μM 6-benzylaminopurine, all of the stem explants formed corms. 170–850 μM paclobutrazol increased corm formation, whereas 1700 μM paclobutrazol inhibited corm development. Inclusion of 66 μM 6-benzylaminopurine in 170 μM paclobutrazol treatment resulted in smaller corms, and bigger corms formed in the combination of 1700 μM paclobutrazol and 66 μM 6-benzylaminopurine. No corms formed in 63–630 μM cycocel treatments. In vitro corm growth was also affected by the culture methods. Deep-layer agitated culture yielded corms of up to 2.03 g, with an average fresh weight of 0.7 g, 40 days after induction. In thin layer cultures, corms were up to 1.87 g, with an average fresh weight of 0.5 g. SDS-PAGE analysis of water-soluble proteins revealed changes of polypeptides with corm growth. Compared to smaller ones, corms over 0.2 g had higher dry matter, carbohydrate and anthocyanin content. These corms had a 99–100% survival rate upon transplanting directly to soil after storage at 4 °C for 10 months. This study indicates that the most economic production method of diploid taro seed corm is by thin-layer liquid culture in Murashige and Skoog medium supplemented with 22–44 μM benzylaminopurine and 8–10% sucrose for 6 weeks. The formed corms can be stored at 4 °C up to 10 months and transplanted directly into soil without acclimatization. This revised version was published online in June 2006 with corrections to the Cover Date.     

Antifungal action of human cathelicidin fragment (LL13-37) on Candida albicans

Human cathelicidin LL37 and its fragments LL13–37 and LL17–32 exhibited similar potencies in inhibiting growth of the yeast Candida albicans. After treatment with 0.5 μM and 5 μM LL13–37, the hyphae changed from a uniformly thick to an increasingly slender appearance, with budding becoming less normal in appearance and cell death could be detected. Only the yeast form and no hyphal form could be observed following exposure to 50 μM LL13–37. LL13–37 at a concentration of 5 μM was able to permeabilize the membrane of yeast form as well as hyphal form of C. albicans since the nuclear stain SYTOX Green was localized in both forms. Mycelia treated with LL13–37 stained with SYTOX Green, but did not stain with MitoTracker deep red, indicating that the mitochondria were adversely affected by LL13–37. Bimane-labeled LL13–37 was able to enter some of the hyphae, but not all hyphae were affected, suggesting that LL37impaired membrane permeability characteristics in some of the hyphae. Reactive oxygen species was detectable in the yeast form of C. albicans cells after treatment with LL13–37 but not in the untreated cells. The results suggest that the increased membrane permeability caused by LL13–37 might not be the sole cause of cell death. It might lead to the uptake of the peptide, which might have some intracellular targets.     

Influence of purinergic modulators on eEPSCs in rat CA3 hippocampal neurons: Contribution of ionotropic ATP receptors

ATP is considered to impact on fast synaptic transmission in several regions of the CNS, including the CA1 and CA3 areas of the hippocampus. The existing paradigm suggests that ATP induces synaptic responses in CA3 pyramidal cells, and a fast ATP-mediated component is observed in cultured hippocampal slices mainly under conditions of a synchronous discharge from multiple presynaptic inputs. We confirmed the existence of a fast ATP-mediated component within electrically evoked EPSCs (eEPSCs) in CA3 neurons of acute slices of the rat hippocampus using a whole-cell patch-clamp recording mode. In approximately 50% of the examined cells, eEPSCs were not completely inhibited by co-applied glutamate receptor antagonists, NBQX (50 μM) and D-APV (25 μM). The residual current was sensitive to ionotropic P2X receptor antagonists, such as suramin (25 μM) and NF023 (2 μM). Known purinergic receptor modulators, ivermectin (10 μM) and PPADS (10 μM), practically did not affect EPSCs, whereas a nonhydrolyzable ATP analog, ATPγS (100 μM), slightly decreased the EPSC amplitude. Moreover, ATPγS (100 μM) at a holding potential of −70 mV generated a slow inward current in most recorded neurons, which was insensitive to glutamate receptor antagonists. This fact is indicative of the ionotropic P2X receptor activation. Neirofiziologiya/Neurophysiology, Vol. 40, No. 1, pp. 21–29, January–February, 2008.     

<Emphasis Type="Italic">In vitro</Emphasis> propagation of an endangered plant species, <Emphasis Type="Italic">Thermopsis turcica</Emphasis> (Fabaceae)

This report deals with micropropagation of the critically endangered and endemic Turkish shrub, Thermopsis turcica using callus, root and cotyledonary explants. Callus cultures were initiated from root and cotyledon explants on MS medium supplemented with 0.5–20 μM NAA or 2,4-D. The root explants were found to be better in terms of quick responding and callusing percentages as compared to the cotyledons. Organogenic callus production with adventitious roots and shoots were obtained on MS medium with only NAA. The calli obtained with NAA, root and cotyledonary explants were cultured with BA and kinetin (2–8 μM) alone or in combination with a low level (0.5 μM) of 2,4-D or NAA. The best regeneration of shoots from root explants was observed on hormone-free MS medium. NAA with BA or kinetin in the medium improved shoot induction from the calli obtained with NAA. Maximum percentage of shoots (93.3%), maximum number of shoots (6.2) and maximun length of shoots (8.22 cm) were achieved from cotyledonary explants at 4 μM BA and 0.5 μM NAA. The presence of 0.5 μM or higher levels of 2,4-D in shoot induction medium inhibited the regeneration in T. turcica explants. 83% of in vitro rooting was attained on pulsed-IBA treated shoots. The regenerated plants with well developed shoots and roots were successfully acclimatized. Application of this study’s results has the potential to conserve T. turcica from extinction.     

Short-and long-term effects of cadmium on transmembrane electric potential (E m) in maize roots

In this study, the effects of Cd on root growth, respiration, and transmembrane electric potential (E _m) of the outer cortical cells in maize roots treated with various Cd concentrations (from 1 μM to 1 mM) for several hours to one week were studied. The E _m values of root cells ranged between −120 and −140 mV and after addition of Cd they were depolarized immediately. The depolarization was concentration-dependent reaching the value of diffusion potential (E _D) when the Cd concentration exceeded 100 μM. The values of E _D ranged between −65 to −68 mV (−66 ± 1.42 mV). The maximum depolarization of E _m was registered approx. 2.5 h after addition of Cd to the perfusion solution and in some cases, partial (Cd > 100 μM) or complete repolarization (Cd < 100 μM) was observed within 8–10 h of Cd treatment. In the time-dependent experiments (0 to 168 h) shortly after the maximum repolarization of E _m a continuous concentration-dependent decrease of E _m followed at all Cd concentrations. Depolarization of E _m was accompanied by both increased electrolyte leakage and inhibition of respiration, especially in the range of 50 μM to 1 mM Cd, with the exception of root cells treated with 1 and 10 μM Cd for 24 and 48 h. Time course analysis of Cd impact on root respiration revealed that at higher Cd concentrations (> 50 μM) the respiration gradually declined (∼ 6 h) and then remained at this lowest level for up to 24 h. All the Cd concentrations used in this experiment induced significant inhibition of root elongation and concentrations higher than 100 μM stopped the root growth within the first day of Cd treatment. Our results suggest that Cd does not cause irreversible changes in the electrogenic plasma membrane H⁺ ATPase because fusicoccin, an H⁺ ATPase activator diminished the depolarizing effect of Cd on the E _m. The depolarization of E _m in the outer cortical cells of maize roots was the result of a cumulative effect of Cd on ATP supply, plasmalemma permeability, and activity of H⁺ ATPase.     

Substrate kinetics of the Acanthamoeba castellanii alternative oxidase and the effects of GMP

In Acanthamoeba castellanii mitochondria, the apparent affinity values of alternative oxidase for oxygen were much lower than those for cytochrome c oxidase. For unstimulated alternative oxidase, the K_Mox values were around 4-5 μM both in mitochondria oxidizing 1 mM external NADH or 10 mM succinate. For alternative oxidase fully stimulated by 1 mM GMP, the KK_Mox values were markedly different when compared to those in the absence of GMP and they varied when different respiratory substrates were oxidized (K_Mox was around 1.2 μM for succinate and around 11 μM for NADH). Thus, with succinate as a reducing substrate, the activation of alternative oxidase (with GMP) resulted in the oxidation of the ubiquinone pool, and a corresponding decrease in K_Mox. However, when external NADH was oxidized, the ubiquinone pool was further reduced (albeit slightly) with alternative oxidase activation, and the K_Mox increased dramatically. Thus, the apparent affinity of alternative oxidase for oxygen decreased when the ubiquinone reduction level increased either by changing the activator or the respiratory substrate availability.     

Biomass production and fatty acid profile of a Scenedesmus rubescens-like microalga

This investigation examined the effects of nitrogen–phosphate combined deficiency on the biomass yield, fatty acid methyl esters (FAME) production and composition from Scenedesmus rubescens-like microalga. A 15-day indoor culture was performed as a 3 × 3 factorial design (NaNO₃ levels: 3, 10 and 20 mM; KH₂PO₄ levels: 20, 50 and 150 μM). The algae grown under medium nitrogen concentration (10 mM) and high phosphate concentration (150 μM) reached the highest biomass (1223.5 ± 152.5 mg/L). Both nitrogen and phosphate had a significant influence on the FAME yield (P < 0.05 and P < 0.0001, respectively). The FAME yield from algae grown under low nitrogen (3 mM) and phosphate concentration (20 μM) increased throughout the experiment and the highest FAME yield (42.2 ± 2.5% of AFDW) as well as C16 and C18 content (95.8 ± 1.6% of AFDW) was achieved under these conditions. Algae grown under medium nitrogen concentration (10 mM) and low phosphate concentration (20 μM) had the highest FAME productivity (426.0 mg/L ± 135.0 mg/L). Thus, the lower nitrogen concentration (3 mM–10 mM) and low phosphate concentration (20 μM) would be an optimal combination tested to produce the most FAME from S. rubescens-like algae.     

Optimisation of procedures for microprojectile bombardment of microspore-derived embryos in wheat

Using the PDS-1000/He Biolistic® Particle Delivery System, the microprojectile travel distance, rupture disk pressure and DNA/gold particle concentrations were assessed in order to optimise short and longer-term β-glucuronidase reporter gene expression in microspore-derived embryos of wheat. The effects were also evaluated of using sterile filter paper to support explants and treatment with a high osmoticum medium (0.2 M mannitol/0.2 M sorbitol or 0.4 M maltose). In the optimised procedure, wheat microspore-derived embryos (MDEs), were placed on filter paper and incubated on medium containing 0.4 M maltose, for 4 h pre- and 45 h post-bombardment. Five μl pAHC25 (0.75 mg ml^-1 in TE buffer) was precipitated onto 25 μl gold particles (60 mg ml^-1 in sterile water), using 20 μl spermidine (0.1 M) and 50 μl CaCl₂ (2.5 M). The particles were centrifuged and resuspended in 75 μl absolute ethanol prior to the preparation of 6 macrocarriers. A microprojectile travel distance of 70 mm, a rupture pressure of 1300 p.s.i., and a vacuum of 29′′ Hg were employed. Maltose at 0.4 M in the support medium was the most important factor influencing GUS activity in bombarded tissues. GUS activity, 1 day post-bombardment, reached 52 ± 17 GUS-positive foci/MDE (mean ± s.e.m, n=3), with 17 ± 4 foci/MDE at 15 days, giving a 3.0-fold increase (p<0.05) compared to expression in MDEs bombarded on medium without a high osmoticum treatment.     

Salivary hydrogen peroxide produced by holding or chewing green tea in the oral cavity

Tea (Camellia sinensis) catechins have been studied for disease prevention. These compounds undergo oxidation and produce H₂O₂. We have previously shown that holding tea solution or chewing tea leaves generates high salivary catechin levels. Herein, we examined the generation of H₂O₂ in the oral cavity by green tea solution or leaves. Human volunteers holding green tea solution (0.1–0.6%) developed salivary H₂O₂ with C_max = 2.9–9.6 μM and AUC_{0 → ∞} = 8.5–285.3 μM min. Chewing 2 g green tea leaves produced higher levels of H₂O₂ (C_max = 31.2 μM, AUC_{0 → ∞} = 1290.9 μM min). Salivary H₂O₂ correlated with catechin levels and with predicted levels of H₂O₂ (C_{max(expected)} = 36 μM vs C_{max(determined)} = 31.2 μM). Salivary H₂O₂ and catechin concentrations were similar to those that are biologically active in vitro. Catechin-generated H₂O₂ may, therefore, have a role in disease prevention by green tea.     

Interactive effects of cadmium and aluminum on growth and antioxidative enzymes in soybean

The effects of Al, Cd and pH on growth, photosynthesis, malondialdehyde (MDA) content, and some antioxidant enzyme activities of the two soybean cultivars with different Al tolerance were determined using a hydroponic culture. There were six treatments as follows: pH 6.5; pH 4.0; pH 6.5 + 1.0 μM Cd; pH 4.0 + 1.0 μM Cd; pH 4.0 + 150 μM Al; pH 4.0 + 1.0 μM Cd + 150 μM Al. The results showed that the low pH (4.0) and Al treatments caused marked reduction in the growth (root and shoot length and dry mass), chlorophyll content (SPAD value) and net photosynthetic rate. Higher malondialdehyde content, superoxide dismutase (SOD) and peroxidase (POD) activities were detected in the plants exposed to both Al and Cd than in those exposed to Al treatment alone. An expressive enhancement of SOD and POD was observed in the plants exposed to 150 μM Al in the comparison with the control plants, especially in Al-sensitive cv. Zhechun 2 which had also significantly higher Al and Cd content than Al tolerant cv. Liao-1. Cd addition increased Al content in the plants exposed to Al + Cd stress, and cv. Zhechun 2 had relatively lower Al content. The present research indicated that Al and Cd are synergistic in their effects on plant growth and some physiological traits.     

Influence of cis-[Re2GABA2Cl4]Cl2 on the antioxidant defense system parameters of normal human blood

The effect of the rhenium complex cis-[Re₂GABA₂Cl₄]Cl₂ on the antioxidant parameters of normal human blood in vitro have been studied. The results suggest that the complex influences various enzymes in the cascade of reactions utilizing active oxygen metabolites. However, the manifestation of this activity varies over the studied concentration range of the complex in the preincubation medium (10^–12-10^–4 M), so the effects appear to be concentration-dependent. The largest differences in antioxidant parameters in comparison with control were observed for the concentrations 10^–8, 10^–5, and 10^–4 M. Thus, correlations between the peroxidation level, superoxide dismutase (SOD) activity, antioxidant factor (F), and indexes of resistance of erythrocytes for hemolysis (TR) were found.     

The Effect of Different Plant Growth Regulators on Adventitious Shoot Formation from Virginia Pine (Pinus virginiana) Zygotic Embryo Explants

The effects of different plant growth regulators on in vitro adventitious shoot formation in Virginia pine (Pinus virginiana Mill.) zygotic embryo explants were quantitatively evaluated. Using Tang and Ouyang (1999) (TE) basal medium supplemented with 11.4 μM indole-3-acetic acid (IAA) and 2.2 μM N⁶-benzyladenine (BA), callus was observed after 3–6 weeks of culture. Calluses were transferred to TE basal medium supplemented with 0.49 μM indole-3-butyric acid (IBA) and 8.8 μM BA for 6–9 weeks, where they produced numerous small shoot primordia. They were then transferred to TE basal medium supplemented with 0.49 μM IBA and 4.4 μM BA to promote growth and elongation of adventitious shoots. After elongated shoots were transferred to TE medium containing 0.05 μM α-naphthaleneacetic acid (NAA) for 6 weeks, adventitious roots were formed. Regenerated plantlets were established in soil in greenhouse.     

Regeneration of garlic plants (allium sativum L., CV. “Chonan”) via cell culture in liquid medium

Summary Aiming at the genetic improvement of garlic cultivars, a cell suspension protocol was established which includes the induction of friable callus, establishment of cells in liquid medium, plating, regeneration, and bulb formation. Calluses of various textures from compact to friable and from green to yellowish were obtained by culturing explants excised from inner leaves of garlic bulbs on Marashig-Shoog (MS) medium with 2,4 dichlorophenoxy acetic acid (2,4-D), (1.1 mg/liter [5.0 μM]), picloram (1.2 mg/liter [5.0 μM]), and kinetin (2.1 mg/liter [10 μM]). Friable callus occurred on MS-A contained 2,4-D alone (1.0 mg/liter [4.52 μM]) and this callus was used to develop cell suspension cultures, which were maintained in liquid MS-B medium with a 2,4-D/benzyl adenine (BA) (0.5 mg/liter [2.25 μM]: 0.5 mg/liter [2.22 μM]) ratio. High plating efficiency was obtained on MS-C medium with different naphthalene acetic acid/BA combinations. Regeneration occurred after transfer of the caulogenic mass to MS-C medium containing 10 mg/liter (74.02 μM) and 20 mg/liter (148.04 μM) adenine for 60 days, followed by transfer to adenine-free medium. Plantlets transplanted to soil showed normal phenology. Shoots grown on modified MS medium supplemented with indolylbutryic acid (3.0 mg/liter [14.7 μM]) stimulated bulb formation by 30 days in culture.     

Multi-target novel neuroprotective compound ITH33/IQM9.21 inhibits calcium entry, calcium signals and exocytosis

Compound ITH33/IQM9.21 (ITH/IQM) belongs to a new family of l-glutamic acid derivatives with antioxidant and neuroprotective properties on in vitro and in vivo models of stroke. Because neuronal damage after brain ischemia is tightly linked to excess Ca²⁺ entry and neuronal Ca²⁺ overload, we have investigated whether compound ITH/IQM antagonises the elevations of the cytosolic Ca²⁺ concentrations ([Ca²⁺]_c) and the ensuing exocytotic responses triggered by depolarisation of bovine chromaffin cells. In fluo-4-loaded cell populations, ITH/IQM reduced the K⁺-evoked [Ca²⁺]_c transients with an IC₅₀ of 5.31 μM. At 10 μM, the compound decreased the amplitude and area of the Ca²⁺ transient elicited by challenging single fura-2-loaded cells with high K⁺, by 40% and 80%, respectively. This concentration also caused a blockade of K⁺-induced catecholamine release at the single-cell level (78%) and cell populations (55%). These effects are likely due to blockade of the whole-cell inward Ca²⁺ currents (IC₅₀ = 6.52 μM). At 10 μM, ITH/IQM also inhibited the Ca²⁺-dependent outward K⁺ current, leaving untouched the voltage-dependent component of I_K. The inward Na⁺ current was unaffected. Inhibition of depolarisation-elicited Ca²⁺ entry, [Ca²⁺]_c elevation and exocytosis could contribute to the neuroprotective effects of ITH/IQM in vulnerable neurons undergoing depolarisation during brain ischemia.     

Tillage effect on seasonal nitrogen availability in corn supplied with legume green manures

Colonization of sorghum by Macrophomina phaseolina in field plots was determined at nitrogen fertilization rates of 0, 56, 112, and 168 kg ha^-1 in 1988 and 0, 84, 168, and 256 kg ha^-1 in 1989. Above ground plant tissue and roots were sampled monthly to determine total nitrogen and percent colonization of root segments by natural inoculum. Root infection was not affected by nitrogen treatment, but was affected by growth stage and environment. High root infection occurred before reproductive development (growth stage 3) in 1988 and was associated with hot, dry weather early in the growing season. In 1989, when the weather was cool and wet, root infection began after reproductive development (growth stage 4). The effect of nitrogen treatments on lesion length was determined in sorghum stalks artificially inoculated with M. phaseolina. Lesion lengths were significantly affected by both nitrogen treatments and growth stage. Lesions were significantly longer with all nitrogen treatments at growth stage 9 than with the no-nitrogen treatment, and lesions tended to increase with increased levels of nitrogen fertilization. Significant increases in lesion length occurred between growth stages 5, 7, and 9 in 1988 and between 7 and 9 in 1989. This study demonstrates that nitrogen fertilization affects colonization of sorghum stalks but not root infection by M. phaseolina.     

Callus proliferation from leaf protoplasts using phenylurea type cytokinin, 4-PU,inBetula platyphylla VAR.Japonica

Summary Protoplasts were isolated from leaves ofBetula platyphylla var.japonica using a 0.6M mannitol solution containing 1% Cellulase Onozuka R-10 and 1% Driselase. The cell division and colony formation were largely enhanced using Murashige and Skoog (1962) liquid medium at half strength (1/2 MS), containing 0.6M mannitol, 0.09M sucrose, and factorial combinations of 0.1–30 μM N-(2-chloro-4-pyridyl)-N′-phenylurea (4-pu) and 0.1–10 μM 1-naphthaleneacetic acid (NAA) or 0.1–30 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The optimal protoplast density was 5–7 × 10⁴/ml. Continuous callus proliferation from protoplasts was achieved by transferring colonies to fresh 1/2 MS agar medium containing 1 μM NAA and 1 μM 4-pu with no mannitol. It appeared that supplementation of the medium with phenylurea type cytokinin, 4-pu gave the successful callus proliferation from the protoplasts ofB. platyphylla.     

In vitro Propagation of Cloudberry (Rubus chamaemorus)

The purpose of this study was to establish conditions for micropropagation of cloudberry (Rubus chamaemorus L.). Cultures were initiated from meristem cultures. When cultures were subcultured from clusters of 3–5 shoots, approximately 70 and 50 shoots were produced per cluster within 6 weeks at 8.9 μM BAP for the female cv. Fjellgull and the male cv. Apollen, respectively. Addition of 5.5 μM GA₃ reduced the number of shoots. Auxins (IBA, NAA) promoted root development in vitro, but inhibited formation of new shoots. However, as much as 85% of shoots rooted without auxin treatment when planted in a peat:sand (80:20 v/v) mixture. Some of the male plants regenerated from shoot tip cultures flowered in the greenhouse within a year after transfer to soil.