Exogenous 6-benzylaminopurine inhibits tip growth and cytokinesis via regulating actin dynamics in the moss Physcomitrium patens

Exogenous BAP but not 2iP disrupts actin structures and induces tip-growth retardation and cytokinesis failure in the moss Physcomitrium patens. Synthetic cytokinins have been widely used to address hormonal responses during plant development. However, exogenous cytokinins can cause a variety of cellular effects. A detailed characterization of such effects has not been well studied. Here, using Physcomitrium patens as a model, we show that the aromatic cytokinin 6-benzylaminopurine (BAP) inhibits tip growth at concentrations above 0.2 µM. At higher concentrations (0.6-1 µM), BAP can additionally block mitotic entry and induce cytokinesis defects and cell death. These effects are associated with altered actin dynamics and structures. By contrast, 2-isopentenyladenine (2iP) does not cause marked defects at various concentrations up to 10 µM, while t-zeatin (tZ) can moderately inhibit moss growth. Our results provide mechanistic insight into the inhibitory effects of BAP on cell growth and cell division and call for attention to the use of synthetic cytokinins for bioassays.

Cost-effectiveness and budget impact analysis of siponimod in the treatment of secondary progressive multiple sclerosis in Italy

BACKGROUND

Siponimod is an effective treatment for patients with secondary progressive multiple sclerosis (SPMS), with active disease evidenced by relapses or imaging features characteristic of multiple sclerosis inflammatory activity, however there is a need to evaluate its economic value and sustainability compared to other disease modifying-therapies (DMTs).

OBJECTIVE

To estimate the siponimod cost-effectiveness profile and its relative budget impact compared with other DMTs, by using the Italian National Healthcare System perspective.

METHODS

We performed: 1) a cost-effectiveness analysis (CEA) vs interferon beta-1b using an analytical Markov model and a life time-horizon, and 2) a budget impact analysis by using 3-years time-horizon. The results were reported as incremental cost-effectiveness ratio (ICER) and net-monetary benefit (NMB) for CEA, using a willingness to pay threshold of €40,000 per QALY gained, and as difference in the overall budget (Euro) between the scenario with and without siponimod for budget impact.

RESULTS

In the base case scenario siponimod resulted cost-effective compared with interferon beta-1b 28,891€ per QALY. Overall, the market access of siponimod was associated to an increased budget of about 3€ millions (+0.9%) in the next 3 years simulated.

CONCLUSION

Compared to interferon beta-1b, siponimod seems to be cost-effective in SPMS patients and sustainable, with less than 1% overall budget increased in the next 3 years. Future studies need to confirm our results in the real word setting and in other countries.

Stick or twist? Cost-effectiveness of siponimod compared with continuing existing disease-modifying therapies in the treatment of active secondary progressive multiple sclerosis in the UK

OBJECTIVE

Identification of the phenotypic transition from relapsing-remitting multiple sclerosis (RRMS) to secondary progressive multiple sclerosis (SPMS) is often delayed due to disease complexity and an unwillingness to withdraw RRMS disease-modifying therapies (DMTs), driven by limited SPMS treatment options. Despite the paucity of clinical evidence for efficacy in patients with SPMS, DMTs licensed for RRMS are frequently continued into the early stages of SPMS. The cost-effectiveness of oral siponimod, an active SPMS DMT, versus continued oral or infused RRMS DMTs for patients with active SPMS, was evaluated.

METHODS

A cohort Markov model based on disease progression through Expanded Disability Status Scale health states, with annual cycles and lifetime horizon, was employed to determine the cost-effectiveness of siponimod from a UK National Health Service (NHS) perspective for patients with active SPMS. Baseline characteristics, health state utility values, hazard ratios for time to 6-month confirmed disability progression, annualized relapse rate ratios and adverse events for siponimod were obtained from the phase 3 EXPAND clinical trial, supplemented by published literature. Published costs, resource use data and comparator efficacy data were obtained from the literature and, in the absence of data, reasonable assumptions were made.

RESULTS

Quality-adjusted life years (QALYs) were greater for siponimod versus all comparators (3.45 versus 2.69-2.83). Incremental cost-effectiveness ratios (ICERs), calculated as cost per QALY, for siponimod versus natalizumab (dominant), ocrelizumab (£4,760), fingolimod (£10,033) and dimethyl fumarate (£15,837) indicated that siponimod was cost-effective at the commonly accepted willingness-to-pay threshold of £30,000/QALY.

CONCLUSIONS

Recognition of active SPMS and treatment of this phenotype with siponimod offers a cost-effective and clinically beneficial treatment approach compared with the continuation of oral or infused RRMS DMTs.

In Vivo Bioengineering of Beta Cells with Immune Checkpoint Ligand as a Treatment for Early-Onset Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is an autoimmune disease caused by autoreactive T cells targeting the insulin-producing beta (β) cells. Despite advances in insulin therapy, T1DM still leads to high morbidity and mortality in patients. A key focus of T1DM research has been to identify strategies that re-establish self-tolerance and suppress ongoing autoimmunity. Here, we describe a strategy that utilizes pretargeting and glycochemistry to bioengineer β cells in situ to induce β-cell-specific tolerance. We hypothesized that β-cell-targeted Ac₄ManNAz-encapsulated nanoparticles deliver and establish β cells with high levels of surface reactive azide groups. We further theorized that administration of a dibenzylcyclooctyne (DBCO)-functionalized programmed death-ligand 1 immunoglobulin fusion protein (PD-L1-Ig) can be readily conjugated to the surface of native β cells. Using nonobese diabetic (NOD) mice, we demonstrated that our strategy effectively and selectively conjugates PD-L1 onto β cells through bioorthogonal stain-promoted azide-alkyne cycloaddition. We also showed that the in vivo functionalized β cells simultaneously present islet-specific antigen and PD-L1 to the engaged T cells, reversing early onset T1DM by reducing IFN-gamma expressing cytotoxic toxic T cells and inducing antigen-specific tolerance.

Siponimod for multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a chronic immune-mediated disease of the central nervous system, with an unpredictable course. Current MS therapies such as disease-modifying therapies focus on treating exacerbations, preventing new exacerbations and avoiding the progression of disability. Siponimod (BAF312) is an oral treatment, a selective sphingosine-1-phosphate (S1P) receptor modulator, for the treatment of adults with relapsing forms of MS including active, secondary progressive MS with relapses.

OBJECTIVES

To assess the benefits and adverse effects of siponimod as monotherapy or combination therapy versus placebo or any active comparator for people diagnosed with MS.

SEARCH METHODS

On 18 June 2020, we searched the Cochrane Multiple Sclerosis and Rare Diseases of the CNS Trials Register, which contains studies from CENTRAL, MEDLINE and Embase, and the trials registry databases ClinicalTrials.gov and WHO International Clinical Trials Registry Platform (ICTRP). We also handsearched relevant journals and screened the reference lists of published reviews and retrieved articles and searched reports (2004 to June 2020) from the MS societies in Europe and America.

SELECTION CRITERIA

We included randomised parallel controlled clinical trials (RCTs) that evaluated siponimod, as monotherapy or combination therapy, versus placebo or any active comparator in people with MS. There were no restrictions on dose or administration frequency.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We discussed disagreements and resolved them by consensus among the review authors. Our primary outcomes wereworsening  disability , relapse and adverse events, and secondary outcomes were annualised relapse rate, gadolinium-enhancing lesions, new lesions or enlarged pre-existing lesions and mean change of brain volume. We independently evaluated the certainty of evidence using the GRADE approach. We contacted principal investigators of included studies for additional data or confirmation of data.

MAIN RESULTS

Two studies (1948 participants) met our selection criteria, 608 controls and 1334 treated with siponimod. The included studies compared siponimod with placebo. Overall, all studies had a high risk of bias due to selective reporting and attrition bias.  Comparing siponimod administered at a dose of 2 mg to placebo, we found that siponimod may reduce the number of participants with disability progression at six months (56 fewer people per 1000; risk ratio (RR) 0.78, 95% confidence interval (CI) 0.65 to 0.94; 1 study, 1641 participants; low-certainty evidence) and annualised relapse rate (RR 0.43, 95% CI 0.34 to 0.56; 2 studies, 1739 participants; low-certainty evidence). But it might lead to little reduction in the number of participants with new relapse (166 fewer people per 1000; RR 0.38, 95% CI 0.15 to 1.00; 1 study, 94 participants; very low-certainty evidence). We observed no evidence of a difference   due to adverse events for siponimod at 2 mg compared to placebo (14 more people per 1000; RR 1.52, 95% CI 0.85 to 2.71; 2 studies, 1739 participants, low-certainty evidence). In addition, due to the high risk of inaccurate magnetic resonance imaging (MRI) data in the two included studies, we could not combine data for active lesions on MRI scans. Both studies had high attrition bias resulting from the unbalanced reasons for dropouts among groups and high risk of bias due to conflicts of interest. Siponimod may reduce the number of gadolinium-enhancing T1-weighted lesions at two years of follow-up (RR 0.14, 95% CI 0.10 to 0.19; P < 0.0001; 1 study, 1641 participants; very low-certainty evidence). There may be no evidence of a difference between groups in the number of participants with at least one serious adverse event excluding relapses (113 more people per 1000; RR 1.80, 95% CI 0.37 to 8.77; 2 studies, 1739 participants; low-certainty evidence) at six months. No data were available regarding cardiac adverse events. In terms of safety profile, the most common adverse events associated with siponimod were headache, back pain, bradycardia, dizziness, fatigue, influenza, urinary tract infection, lymphopenia, nausea, alanine amino transferase increase and upper respiratory tract infection. These adverse events have dose-related effects and rarely led to discontinuation of treatment.

AUTHORS' CONCLUSIONS

Based on the findings of the RCTs included in this review, we are uncertain whether siponimod interventions are beneficial for people with MS. There was low-certainty evidence to support that siponimod at a dose of 2 mg orally once daily as monotherapy compared with placebo may reduce the annualised relapse rate and the number of participants who experienced disability worsening, at 6 months. However, the certainty of the evidence to support the benefit in reducing the number of people with a relapse is very low.  The risk of withdrawals due to adverse events requires careful monitoring of participants over time. The duration of all studies was less than 24 months, so the efficacy and safety of siponimod over 24 months are still uncertain, and further exploration is needed in the future. There is no high-certainty data available to evaluate the benefit on MRI outcomes. We assessed the certainty of the body of evidence for all outcomes was low to very low, downgraded due to serious study limitations, imprecision and indirectness. We are uncertain whether siponimod is beneficial for people with MS. More new studies with robust methodology and longer follow-up are needed to evaluate the benefit of siponimod for the management of MS and to observe long-term adverse effects. Also, in addition to comparing with placebo, more new studies are needed to evaluate siponimod versus other therapeutic options.

Indirect comparisons of siponimod with fingolimod and ofatumumab in multiple sclerosis: assessing the feasibility of propensity score matching analyses

OBJECTIVE

Head-to-head trials comparing siponimod with fingolimod or ofatumumab in patients with multiple sclerosis (MS) are lacking. Instead, the comparative efficacy of siponimod can be derived from indirect treatment comparisons (ITCs). We assessed the suitability of ITCs leveraging individual patient data from relevant phase III trials across different MS phenotypes.

METHODS

One siponimod trial in patients with secondary progressive MS (SPMS), four fingolimod trials (three in relapsing-remitting MS [RRMS], and one in primary progressive MS [PPMS]), and two ofatumumab trials in relapsing MS (RMS) were considered. The suitability of ITCs was evaluated based on trial design, patient eligibility criteria, baseline patient characteristics, placebo response, and outcome definitions for each trial. Analyses deemed feasible were conducted using one-to-one propensity score matching (PSM).

RESULTS

An ITC between siponimod in SPMS and either fingolimod in RRMS or ofatumumab in RMS was not feasible because of insufficient overlap in key patient characteristics (e.g. disability level and relapse history) and differences in placebo response. However, a comparison between siponimod in SPMS and fingolimod in PPMS was feasible because of sufficient overlap in eligibility criteria and baseline characteristics. One-to-one PSM demonstrated siponimod was favored relative to fingolimod for time to 6- and 3-month confirmed disability progression though not significantly different (hazard ratio 0.76 [95% confidence interval 0.48-1.20; p-value = .240] and hazard ratio 0.80 [95% confidence interval 0.52-1.22; p-value = .300], respectively).

CONCLUSIONS

For trials in MS, clinical phenotype is an important determinant of ITC feasibility. An ITC between siponimod in SPMS and either fingolimod in RRMS or ofatumumab in RMS was not feasible. The only feasible comparison was between siponimod in SPMS and fingolimod in PPMS.

Melatonin mitigated circadian disruption and cardiovascular toxicity caused by 6-benzylaminopurine exposure in zebrafish

As a highly effective plant hormone, the overuse of 6-benzylaminopurine (6-BA) may pose potential threats to organisms and the environment. Melatonin is widely known for its regulation of sleep rhythm, and it also shows a beneficial effect in a variety of adverse situations. In order to investigate the harm of 6-BA to vertebrates and whether melatonin can reverse the toxicity induced by 6-BA, we analyzed the circadian rhythm and cardiovascular system of zebrafish, and further clarified the role of the thyroid endocrine system. The exposure of well-developed embryos started at 2 hpf, then 6-BA and/or melatonin were carried out. The results indicated that 6-BA disturbed the rhythmic activities of the larvae, increased wakefulness, correspondingly reduced their rest, and induced disrupted clock gene expression. Video analysis and qRT-PCR data found that zebrafish under 6-BA exposure showed obvious cardiovascular morphological abnormalities and dysfunction, and the mRNA levels of cardiovascular-related genes (nkx2.5, gata4, myl7, vegfaa and vegfab) were significantly down-regulated. In addition, altered thyroid hormone content and hypothalamus-pituitary-thyroid (HPT) axis-related gene expression were also clearly observed. 1umol/L of melatonin had little effect on zebrafish, but its addition could significantly alleviate the circadian disturbance and cardiovascular toxicity caused by 6-BA, and simultaneously played a regulatory role in thyroid system. Our research revealed the adverse effects of 6-BA on zebrafish larvae and the protective role of melatonin in circadian rhythm, cardiovascular and thyroid systems.

Exploring nordihydroguaretic acid (NDGA) as a plausible neurotherapeutic in the experimental paradigm of autism spectrum disorders targeting nitric oxide pathway

The present study investigates the neuro-protective ability of nordihydroguaretic acid (NDGA) in the experimental paradigm of autism spectrum disorders (ASD) and further decipher the nitric oxide pathway's role in its proposed action. An intracerebroventricular infusion of 4 μl of 1 M PPA was given in the lateral ventricle's anterior region to induce autism-like phenotype in male rats. Oral administration of NDGA (5, 10 & 15 mg/kg) was initiated from the 3^rd day lasting till the 28th day. L-NAME (50 mg/kg) and L-Arginine (800 mg/kg) were also given individually and combined to explore NDGA's ability to act via the nitric oxide pathway. Behavior tests for sociability, stereotypy, anxiety, depression, novelty, repetitive and perseverative behavior were carried out between the 14th and 28th day. On the 29th day, animals were sacrificed, and mitochondrial complexes and oxidative stress parameters were evaluated. We also estimated the levels of neuroinflammatory and apoptotic markers such as TNF-α, IL-6, NF-κB, IFN-γ, HSP-70, and caspase-3. To assess the involvement of the nitric oxide pathway, levels of iNOS and homocysteine were estimated. Treatment with NDGA significantly restored behavioral, biochemical, neurological, and molecular deficits. Hence, NDGA can be used as a neurotherapeutic agent in ASD. Targeting nitric oxide pathway mediated oxidative & nitrosative stress responsible for behavioral, biochemical, and molecular alterations via modulating nitric oxide pathway. The evaluation of iNOS and homocysteine levels conclusively establishes the nitric oxide pathway's role in causing behavioral, biochemical & molecular deficits and NDGA's beneficial effect in restoring these alterations.

DNA Adductomics by mass tag prelabeling

RATIONALE

As a new approach to DNA adductomics, we directly reacted intact, double-stranded (ds)-DNA under warm conditions with an alkylating mass tag followed by analysis by liquid chromatography/mass spectrometry. This method is based on the tendency of adducted nucleobases to locally disrupt the DNA structure (forming a "DNA bubble") potentially increasing exposure of their nucleophilic (including active hydrogen) sites for preferential alkylation. Also encouraging this strategy is that the scope of nucleotide excision repair is very broad, and this system primarily recognizes DNA bubbles.

METHODS

A cationic xylyl (CAX) mass tag with limited nonpolarity was selected to increase the retention of polar adducts in reversed-phase high-performance liquid chromatography (HPLC) for more detectability while maintaining resolution. We thereby detected a diversity of DNA adducts (mostly polar) by the following sequence of steps: (1) react DNA at 45°C for 2 h under aqueous conditions with CAX-B (has a benzyl bromide functional group to label active hydrogen sites) in the presence of triethylamine; (2) remove residual reagents by precipitating and washing the DNA (a convenient step); (3) digest the DNA enzymatically to nucleotides and remove unlabeled nucleotides by nonpolar solid-phase extraction (also a convenient step); and (4) detect CAX-labeled, adducted nucleotides by LC/MS2 or a matrix-assisted laser desorption/ionization (MALDI)-MS technique.

RESULTS

Examples of the 42 DNA or RNA adducts detected, or tentatively so based on accurate mass and fragmentation data, are as follows: 8-oxo-dGMP, ethyl-dGMP, hydroxyethyl-dGMP (four isomers, all HPLC-resolved), uracil-glycol, apurinic/apyrimidinic sites, benzo[a]pyrene-dGMP, and, for the first time, benzoquinone-hydroxymethyl-dCMP. Importantly, these adducts are detected in a single procedure under a single set of conditions. Sensitivity, however, is only defined in a preliminary way, namely the latter adduct seems to be detected at a level of about 4 adducts in 109 nucleotides (S/N ~30).

CONCLUSIONS

CAX-Prelabeling is an emerging new technique for DNA adductomics, providing polar DNA adductomics in a practical way for the first time. Further study of the method is encouraged to better characterize and extend its performance, especially in scope and sensitivity.

The Synthesis of Benzyl Acetate as a Fragrance and Flavoring Agent with Green Solvents

Benzyl acetate, which has a crucial role in the industry as a flavor and fragrance component, is important for human health to be obtained with a green and clean process. For this purpose, the esterification reaction of acetic acid (AA) and benzyl alcohol (BA) was investigated using five different ionic liquids (ILs) as catalysts. 1-Ethyl-3-methylimidazolium hydrogen sulfate, [EMIM] [HSO₄], 1-Ethyl-3-methylimidazolium tetrafluoroborate [EMIM] [BF₄], 1-methyl-3-octylimidazolium tetrafluoroborate [OMIM] [BF₄], 1-ethyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl] imide [EMIM] [NTf₂], and 1,3-diethylimidazolium bis [(trifluoromethyl)sulfonyl] imide [DEIM] [NTf₂] were used as catalysts. The best catalytic performance was obtained with 1-Ethyl-3-methylimidazolium hydrogen sulfate, [EMIM] [HSO₄]. The influence of different anions and cations in the IL's structure, the reaction conditions such as initial acid/alcohol ratio, the catalyst amount, the reaction temperature, and the time on conversion were observed. The Box-Behnken experimental design of response surface methodology was applied to estimate the relationship between acid conversion (%) and reaction parameters. According to the model, in all esterification experiments carried out at 110°C, the optimum conditions for maximum conversion were AA:BA molar ratio of 1:1, IL molar ratio of 0.66, and reaction time 4 hours. Under these conditions, 90.34% acid conversion was achieved. [EMIM] [HSO₄] can be used for up to three cycles with minimal loss in activity.

Efficient mineralization of gaseous benzyl chloride by VUV/UV photodegradation in humid air

VUV/UV photodegradation technology, which is free of catalysts or oxidants, has been regarded as an efficient method to decompose gaseous VOCs. However, the mineralization of gaseous VOCs by VUV/UV photodegradation has seldom been discussed systematically. In this work, the mineralization of benzyl chloride in humid air is comprehensively investigated and the potential contributors in the system (i.e., light wavelength, O₂ and H₂O) are discussed. As a result, more than 95.0% benzyl chloride is mineralized at 40 min in humid air with 80% relative humidity (RH) despite its initial concentrations (i.e., ranging from 4 to 20 ppm). It is found that both 185-nm VUV light and H₂O significant contribute to the efficient mineralization of benzyl chloride in humid air, while O₂ only has a limited effect to the efficient mineralization of benzyl chloride in humid air. The introduction of H₂O into the VUV/UV photodegradation can reduce the emission of ozone obviously. These findings are significant inspiration to application of the VUV/UV photodegradation technology on the treatment of gaseous VOCs in the actual air atmosphere.

Cost Effectiveness and Budget Impact of Siponimod Compared to Interferon Beta-1a in the Treatment of Adult Patients with Secondary Progressive Multiple Sclerosis with Active Disease in Switzerland

OBJECTIVE

The study aim was to evaluate the cost effectiveness and budget impact of siponimod compared to interferon beta-1a for adult patients with secondary progressive multiple sclerosis (SPMS) with active disease, from a Swiss health insurance perspective.

METHODS

We conducted an analysis using a Markov cohort model with a cycle length of 1 year, life-long time horizon, and discount rate of 3% for cost and health outcomes. We used a matching-adjusted indirect comparison to estimate clinical outcomes using data from the EXPAND randomised controlled trial of siponimod vs placebo and the Nordic SPMS randomised controlled trial of interferon beta-1a vs placebo as the basis for estimates of disability progression and relapse outcomes. We used 6-month confirmed disability progression results to estimate disability progression in the base-case analysis. We calculated quality-adjusted life-years (QALYs) based on an external study that administered the EQ-5D-3L questionnaire to European patients with multiple sclerosis. We included costs (Swiss Franc (CHF), year 2020) of drug acquisition/administration, adverse events and disease management. We also performed a budget impact analysis to estimate the cost over the first 3 years of introducing siponimod.

RESULTS

For the base case, siponimod resulted in mean incremental costs of CHF 84,901 (siponimod: CHF 567,838, interferon beta-1a: CHF 482,937) and mean incremental QALYs of 1.591 (siponimod: 7.495, interferon beta-1a: 5.905), leading to an incremental cost-effectiveness ratio of CHF 53,364 per QALY gained. In the probabilistic sensitivity analysis, the probability of the cost effectiveness of siponimod assuming a willingness-to-pay threshold of CHF 100,000 per QALY gained was 90%. Siponimod was projected to result in drug administration costs for siponimod of CHF 23,817,856 in the first 3 years after introduction, accompanied by large cost offsets in drug acquisition of other multiple sclerosis drugs. Considering drug administration, monitoring and adverse event management costs, it was estimated to result in additional healthcare costs in Switzerland of CHF 2,177,021.

CONCLUSIONS

In the base-case analysis, we found that siponimod may be cost effective for treating Swiss adult patients with SPMS with active disease. The results of the cost-effectiveness analyses are valid under the assumption that the efficacy of siponimod and the comparators on disability progression for the overall SPMS population would be the same in the active SPMS population.

CLINICAL TRIAL IDENTIFIER

NCT01665144. This economic evaluation was based on the EXPAND trial.

Application of abscisic acid and 6-benzylaminopurine modulated morpho-physiological and antioxidative defense responses of tomato (Solanum lycopersicum L.) by minimizing cobalt uptake

A hydroponic study was conducted to determine the effects of single and/or combined application of different doses (0, 5 and 10 μM L^-1) of abscisic acid (ABA) and 6-benzylaminopurine (BAP) on cobalt (Co) accumulation, morpho-physiological and antioxidative defense attributes of tomato (Solanum lycopersicum L.) exposed to severe Co stress (400 μM L^-1). The single Co treatment (T1), prominently decreased tomato growth, relative water contents, photosynthetic pigments (chlorophyll a and chlorophyll b), whereas enhanced oxidative stress and Co accumulation in shoot and root tissues. Nonetheless, the supplementation of ABA and 6-BAP via nutrient media significantly (P < 0.05) enhanced plant biomass, root morphology and chlorophyll contents of tomato, compared to only Co treatment (T1). Moreover, the oxidative stress indicators such as malondialdehyde, proline and H₂O₂ contents were ameliorated through activation of enzymatic antioxidant activities i.e. ascorbate peroxidase, superoxide dismutase, catalase, and peroxidase, in growth modulator treatments in comparison to T1. The Co uptake, translocation (TF) and bioaccumulation factor (BAF) by shoot and root tissues of tomato were significantly reduced under all the treatments than that of T1. The supply of 6-BAP alone or in combination with ABA at 10 μM L^-1 application (T7) rate was found the most effective to reduce Co accumulation in the roots and shoots by 48.4% and 70.2% respectively than T1 treatment. It can be concluded that two plant growth modulators could improve the stress tolerance by inhibition of Co uptake in tomato plants.

Gravistimulation effects on Oryza sativa amino acid profile, growth pattern and expression of OsPIN genes

Gravity is an important ecological factor regulating plant growth and developmental processes. Here we used various molecular and biochemical approaches to investigate artificial and normal gravistimulation's effect on the early growth stages of rice (Oryza sativa L.) by changing the orientations of Petri dishes. Rate of amino acid formation, root and shoot growth, and OsPIN expression was significantly higher under gravistimulation compared with the control. Clinostat rotation positively affected plant growth and amino acid profile. However, under normal gravity, vertical-oriented seedlings showed high amino acid levels compared with clinostat, 90°-rotated, and control seedlings. Similarly, seedling growth significantly increased with 90°-rotated and vertical orientations. Artificial gravity and exogenous indole-3-acetic acid induced OsPIN1 expression in the roots, root shoot junction, and shoots of clinorotated seedlings. Phenyl acetic acid induced OsPIN1 expression in the roots and root shoot junction of clinorotated seedlings but not in the shoot. The current study suggests that OsPIN1 is differentially regulated and that it might be involved in the regulation of plant growth. Conversely, OsPIN2 and OsPIN3a are gravity sensors and highly induced in the roots and root shoot junctions of vertical and 90°-rotated seedlings and play an important role in stress conditions. Thus, on exposure to gravity, hormones, and UV-C radiation, these genes are highly regulated by jasmonic acid, 6-benzylaminopurine and gibberellic acid.

Antimicrobial Chrysophaentin Analogs Identified from Laboratory Cultures of the Marine Microalga Chrysophaeum taylorii

A laboratory culture of the colonial marine alga Chrysophaeum taylorii NIES-1699 yielded a set of new bioactive chrysophaentin analogs, and their structures were determined by HRESIMS and NMR spectroscopy. Differences in the metabolites identified between cultured C. taylorii NIES-1699 and field-collected strains from the U.S. Virgin Islands revealed additional structure-activity relationships for the Gram-positive antibiotic activity of the chrysophaentins. The presence of new hemichrysophaentins and a C-C linked biphenyl analog suggest novel features of their biosynthetic pathway. Bayesian analysis of the alignment of the 18S rRNA gene places the microalga C. taylorii in the pelagophyte clade.

Nanocomposite Porous Microcarriers Based on Strontium-Substituted HA- g-Poly(γ-benzyl-l-glutamate) for Bone Tissue Engineering

Porous microcarriers have aroused increasing attention recently, which can create a protected environment for sufficient cell seeding density, facilitate oxygen and nutrient transfer, and well support the cell attachment and growth. In this study, porous microcarriers fabricated from the strontium-substituted hydroxyapatite- graft-poly(γ-benzyl-l-glutamate) (Sr10-HA- g-PBLG) hybrid nanocomposite were developed. The surface grating of PBLG, the micromorphology and element distribution, mechanical strength, in vitro degradation, and Sr²⁺ ion release of the obtained Sr10-HA- g-PBLG porous microcarriers were investigated, respectively. The grafting ratio and the molecular weight of the grafted PBLG of Sr10-HA- g-PBLG could be effectively controlled by varying the initial ratio of BLG-NCA to Sr10-HA-NH₂. The microcarriers exhibited a highly porous and interconnected microstructure with the porosity of about 90% and overall density of 1.03-1.06 g/cm³. Also, the degradation rate of Sr10-HA-PBLG microcarriers could be effectively controlled and long-term Sr²⁺ release was obtained. The Sr10-HA-PBLG microcarriers allowed cells adhesion, infiltration, and proliferation and promoted the osteogenic differentiation of rabbit adipose-derived stem cells (ADSCs). Successful healing of femoral bone defect was proved by injection of the ADSCs-seeded Sr10-HA-PBLG microcarriers in a rabbit model.

[Effect of Organic Carbon Source on Start-up and Operation of the CANON Granular Sludge Process]

The effect of organic carbon on the start-up and operation of the CANON granular sludge process was investigated in two SBR reactors with different strategies:gradually increased organic carbon concentration (R1) and without organic carbon (R2). The results showed that adding 50 mg·L^-1 organic carbon accelerated the start-up of the CANON granular sludge process. R1 and R2 were started up in 23 d and 32 d, respectively. Moreover, the appropriate organic carbon enhanced the activity of AOB, AnAOB, and denitrification, increasing the ammonia removal rates and total nitrogen (TN) removal rates. The maximum ammonia removal rates and total nitrogen removal rates of R1 were 92% and 88%, respectively. The maximum ammonia removal rates and total nitrogen removal rates of R2 were 89% and 80%, respectively. Further tests showed that excessive organic carbon concentration decreased the activity of AOB and AnAOB and reduced the removal efficiency of ammonia and total nitrogen. Adding organic carbon promoted denitrification activity and increased nitrogen removal efficiency.

Persimmon Fruit Powder May Substitute Indolbi, a Synthetic Growth Regulator, in Soybean Sprout Cultivation

Soybean sprouts are a major food item in Korea. Various studies have been carried out to enhance their yield and nutritional values. The objective of the present study was to examine the influence of persimmon fruit powder and Indolbi, a synthetic plant growth regulator, on the yield and nutritional value of soybean sprouts. Seeds were soaked in tap water containing 0.5%, 1.0%, 2.5% and 5.0% (w/v) persimmon fruit powder and the samples were named as PT-1, PT-2, PT-3, and PT-4, respectively. The yield increment was almost doubled in PT-3 and PT-4 than in the Indolbi treated sprouts on basis of the control. Vitamin C, isoflavones, and total phenolic contents as well as antioxidant potentials (determined by 1,1-diphenyl-2-picrylhydrazyl and superoxide anion radical scavenging assays) were also significantly (p < 0.05) higher in PT-3 compared to the Indolbi treatment and the control. However, total free amino acid and magnesium contents of Indolbi- applied sprouts were higher than in the fruit powder treatments. The overall results of the present study showed that persimmon fruit powder can be an option to enhance the yield and nutritional value of soybean sprouts since, due to potential health hazards, the use of synthetic chemicals like Indolbi is less preferred than the natural products.

mRNA imaging in the chloroplast of Chlamydomonas reinhardtii using the light-up aptamer Spinach

Light-up aptamers are practical tools to image RNA localization in vivo. A now classical light-up aptamer system is the combination of the 3,5-difluoro-4-hydroxybenzylidene (DFHBI) fluorogen and the RNA aptamer Spinach, which has been successfully used in bacterial and mammalian cells. However, light-up aptamers have not been used in algae. Here, we show that a simple vector, carrying Spinach, transcriptionally fused to the aphA-6 gene, can be effectively used to generate a functional light-up aptamer in the chloroplast of Chlamydomonas reinhardtii. After incubation with DFHBI, lines expressing the aphA-6/Spinach mRNA were observed with laser confocal microscopy to evaluate the functionality of the light-up aptamer in the chloroplast of C. reinhardtii. Clear and strong fluorescence was localized to the chloroplast, in the form of discrete spots. There was no background fluorescence in the strain lacking Spinach. Light-up aptamers could be further engineered to image RNA or to develop genetically encoded biosensors in algae.

[Determination of 6 kinds of plant growth regulator in bean sprout by ultra high performance liquid chromatography-tandem mass spectrometry]

OBJECTIVE

A method for the simultaneous determination of 6 plant growth regulator (PGR) residues in bean sprout was developed by ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). 6-Benzylaminopurine, isopentennyladenine, 4-chlorophenoxyacetic acid, 4-fluorophenoxyacetic acid, indole-3- acetic acid and indole-3-butyric acid were concerned.

METHODS

Bean sprout samples were extracted by acetonitrile and QuEChERS extraction kit, purified by C18 powers. After centrifugation, the sample liquids was diluted 10 times by ultrapure water. The chromatographic analysis was carried out on an waters acquity UPLC BEH C18 column( 100 mm x 2.1 mm, 1.7 microm). The analyzer confirmed and quantified by mass spectrum of triple quadrupole in the multiple reaction monitoring (MRM) mode and quantified by matrix-matched external standard method.

RESULTS

The calibration curves showed good linearity in each range with correlation coefficients greater than 0.998. 3 levels spiked recoveries were carried out using blank bean sprout extraction as substrate, the recoveries ranged from 84.2% to 107.5%, the relative standard deviations (RSDs) ranged from 3.08% to 12.71%. The qualitative limits of detections (S/N = 3) were 0.03-3.0 microg/kg and the quantitative limits(S/N = 10) were 0.1-10.0 microg/kg for the 6 PGRs.

CONSLUSION

The method is simple and easy to operate, with less organic reagent, high sensitivity and good stability. It is suitable for the detection of 6 kinds of plant growth regulators in bean sprouts.

[Effect of Chemical Constituents from Glycyrrhiza uralensis Induced by Exogenous 6-Benzylaminopurine in Different Growth Periods]

OBJECTIVE

To study the effect of chemical constituents from Glycyrrhiza uralensis induced by exogenous 6-benzylaminopurine( 6-BA) in different growth periods, aim to explore the regulatory network of Glycyrrhiza uralensis.

METHODS

The transplants of two-year-old Glycyrrhiza uralensis were subjected to four concentrations of 6-BA( 15,20,50,100 mg / L) at June and July. The content of seven kinds of chemical constituents including glycyrrhizic acid, liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin, liquiritin apioside,isoliquiritin apioside were determined by HPLC. Then long-term dynamic changes of the content of seven chemical compositions were analyzed.

RESULTS

In June, the content of seven compositions increased remarkably after 6-BA stimulating than that in July. Seven kinds of chemical constituents increased remarkably after 100 mg / L 6-BA stimulating for 3 months, and the increase rates were59. 34%,71. 14%,57. 31%,16. 36%,30. 17%,80. 26%,91. 90%,respectively. The greatest impact was glycyrrhizic acid with different concentration stimulating. 6-BA stress had a protection ability against the decrease of flavonoids in licorice under natural growth condition. The treatment of 6-BA had effect to the content of Glycyrrhiza uralensis,but hardly altered the ratio of their chemical composition.

CONCLUSION

A regulatory network is existed among medicinal ingredients of Glycyrrhiza uralensis. Glycyrrhizic acid and flavonoids accumulation of Glycyrrhiza uralensis can be affected by exogenous 6-BA stimulation in certain case.

DNA METHYLATION ANALYSIS DURING THE OPTIMIZATION OF Agrobacterium-MEDIATED TRANSFORMATION OF SOYBEAN

Soybean is recognized as one of the plants which are very difficult to be transformed. Considering the low transformation efficiency of soybean, we aimed to determine the effect of 6-benzylaminopurine (6-BA), shoot induction time, and infection time of Agrobacterium on the clonal propagation of Glycine max. Results showed that 1.6 mg/L 6-BA could be optimal to promote the induction of adventitious shoots. An induction time of 15 d was considered optimal for the actual experiment involving soybean shoot induction. Agrobacterium was cultured until an OD600 = 0.8 was reached for an infection time of 30 min; this infection time may be optimal to promote soybean transformation. Whole genome DNA methylation was analyzed by high-performance liquid chromatography (HPLC)-assisted quantification, and DNA methylation result is consistent with the phenotypic data of shoot development. In addition, two methylation-related genes (Decrease in DNA methylation 1 and DNA methyltransferases chromomethylase 2) were analyzed to determine expression differences by qRT-PCR in the shoots that were developed under different experimental conditions. In general, the expression values of these genes were normally downregulated under the recommended experimental conditions of soybean regeneration. This study showed the overall methylation changes in the in vitro culture of soybean, as affected by several variable parameters, which is useful to promote the transformation efficiency of soybean.

Changes in the Metabolome of Picea balfouriana Embryogenic Tissues That Were Linked to Different Levels of 6-BAP by Gas Chromatography-Mass Spectrometry Approach

Embryogenic cultures of Picea balfouriana, which is an important commercial species for reforestation in Southern China, easily lose their embryogenic ability during long-term culture. Embryogenic tissue that proliferated at lower concentrations (3.6 μM and 2.5 μM) of 6-benzylaminopurine (6-BAP) were more productive, and generated 113 ± 6 and 89 ± 3 mature embryos per 100 mg embryogenic tissue, respectively. A metabolomic approach was used to study the changes in metabolites linked to embryogenic competence related to three different 6-BAP concentrations (2.5 μM, 3.6 μM, and 5 μM). A total of 309 compounds were obtained, among which 123 metabolites mapped to Kyoto Encyclopedia of Genes and genomes (KEGG) pathways. The levels of 35 metabolites were significantly differentially regulated among the three 6-BAP treatments, and 32 metabolites differed between the 2.5 μM and 5 μM treatments. A total of 17 metabolites appeared only once among the three comparisons. The combination of a score plot and a loading plot showed that in the samples with higher embryogenic ability (3.6 μM and 2.5 μM), up-regulated metabolites were mostly amino acids and down-regulated metabolites were mostly primary carbohydrates (especially sugars). These results suggested that 6-BAP may influence embryogenic competence by nitrogen metabolism, which could cause an increase in amino acid levels and higher amounts of aspartate, isoleucine, and leucine in tissues with higher embryogenic ability. Furthermore, we speculated that 6-BAP may affect the amount of tryptophan in tissues, which would change the indole-3-acetic acid levels and influence the embryogenic ability.

The interaction between nitrogen availability and auxin, cytokinin, and strigolactone in the control of shoot branching in rice (Oryza sativa L.)

Nitrogen availability and cytokinin could promote shoot branching in rice, whereas auxin and strigolactone inhibited it. The interaction between nitrogen availability and the three hormones is discussed. Rice shoot branching is strongly affected by nitrogen availability and the plant hormones auxin, cytokinin, and strigolactone; however, the interaction of them in the regulation of rice shoot branching remains a subject of debate. In the present study, nitrogen and the three hormones were used to regulate rice tiller bud growth in the indica rice variety Yangdao 6. Both nitrogen and CK promoted shoot branching in rice, whereas auxin and SL inhibited it. We used HPLC to determine the amounts of endogenous IAA and CK, and we used quantitative real-time PCR analysis to quantify the expression levels of several genes. Nitrogen enhanced the amount of CK by promoting the expression levels of OsIPTs in nodes. In addition, both nitrogen and CK downregulated the expression of genes related to SL synthesis in root and nodes, implying that the inhibition of SL synthesis by nitrogen may occur at least partially through the CK pathway. SL did not significantly reduce the amount of CK or the expression levels of OsIPT genes, but it did significantly reduce the amount of auxin and the auxin transport capacity in nodes. Auxin itself inhibited CK synthesis and promoted SL synthesis in nodes rather than in roots. Furthermore, we found that CK and SL quickly reduced and increased the expression of FC1 in buds, respectively, implying that FC1 might be a common target for the CK and SL pathways. Nitrogen and auxin delayed expression change patterns of FC1, potentially by changing the downstream signals for CK and SL.