Induction Stage Research Articles

Time measurement in insect photoperiodism: The role of photophase duration and light intensity

The initial stages of diapause induction - as summer gives way to autumn - involve a process of time measurement in which the duration of daylength (or nightlength) is determined by a photoperiodic 'clock' based upon the circadian system. In many insects so far examined, a photophase of sufficient duration and illuminance resets a photoperiodic oscillator to a constant phase equivalent to the beginning of the 'subjective night' (Circadian time, CT 12 h) whereupon it proceeds to measure nightlength in a clock of the external coincidence type. A possible exception may be found in the linden bug, Pyrrhocoris apterus, which - in laboratory studies using relatively low light intensity - suggests that daylength is measured rather than the night. Earlier studies of photoperiodic responses (pupal diapause induction) in the flesh fly Sarcophaga argyrostoma, however, showed that 'weak' or short light pulses giving rise to Type 1 phase response curves could be converted by increasing light intensity to Type 0 responses that phase set the oscillation to the beginning of the subjective night (CT 12 h) whereupon it could begin to measure the night. Based upon these data it is therefore suggested that the photoperiodic clock in P. apterus might also measure nightlength if the bugs were exposed to photophases of higher irradiance simulating daytime exposure to the light intensity experienced by these diurnally active insects in their natural environment.

Influence of MgO on the Hydration and Shrinkage Behavior of Low Heat Portland Cement-Based Materials via Pore Structural and Fractal Analysis

Currently, low heat Portland (LHP) cement is widely used in mass concrete structures. The magnesia expansion agent (MgO) can be adopted to reduce the shrinkage of conventional Portland cement-based materials, but very few studies can be found that investigate the influence of MgO on the properties of LHP cement-based materials. In this study, the influences of two types of MgO on the hydration, as well as the shrinkage behavior of LHP cement-based materials, were studied via pore structural and fractal analysis. The results indicate: (1) The addition of reactive MgO (with a reactivity of 50 s and shortened as M50 thereafter) not only extends the induction stage of LHP cement by about 1–2 h, but also slightly increases the hydration heat. In contrast, the addition of weak reactive MgO (with a reactivity of 300 s and shortened as M300 thereafter) could not prolong the induction stage of LHP cement. (2) The addition of 4 wt.%–8 wt.% MgO (by weight of binder) lowers the mechanical property of LHP concrete. Higher dosages of MgO and stronger reactivity lead to a larger reduction in mechanical properties at all of the hydration times studied. M300 favors the strength improvement of LHP concrete at later ages. (3) M50 effectively compensates the shrinkage of LHP concrete at a much earlier time than M300, whereas M300 compensates the long-term shrinkage more effectively than M50. Thus, M300 with an optimal dosage of 8 wt.% is suggested to be applied in mass LHP concrete structures. (4) The addition of M50 obviously refines the pore structures of LHP concrete at 7 days, whereas M300 starts to refine the pore structure at around 60 days. At 360 days, the concretes containing M300 exhibits much finer pore structures than those containing M50. (5) Fractal dimension is closely correlated with the pore structure of LHP concrete. Both pore structure and fractal dimension exhibit weak (or no) correlations with shrinkage of LHP concrete.

Effect of antioxidants and growth regulators on shoot organogenesis in the apical meristem culture of <i>Fragaria × ananassa</i> (Duchesne ex Weston) Duchesne ex Rozier

The initiation of strawberries into in vitro culture is known to be complicated by the inhibition of organogenesis by phenolic oxidation products. An important role in this process is given to the selection of growth regulators that increase meristematic cell activity and shoot proliferation at the stage of organogenesis induction. The present study aims to obtain a viable apical meristem culture of garden strawberry and to study the effect of different antioxidants (reduced glutathione (RG); a new preparation, i.e., a mechanical composite (MC) on the basis of biogenic silicon and green tea catechins and plant growth regulators (6-benzylaminopurine; thidiazuron) on the initiation of axillary shoot formation in strawberry meristem culture. Terminal buds containing an apical meristem and two leaf primordia isolated from the stolons of two garden strawberry cultivars (Sunny Meadow and Festival Chamomile) were used as primary explants for the initiation of strawberries into in vitro culture. It was found for the first time that the MC exhibits higher antioxidant activity as compared to reduced glutathione, reduces darkening of initial explants, as well as enhancing regeneration up to 13.0% at p ≤ 0.05. Furthermore, the best effect on the formation of microshoots per explant is observed toward the end of material introduction into in vitro culture when combining the MC with growth regulators in the culture medium. Here, the effect of strawberry cultivar on explant regeneration and the number of microshoots per explant are insignificant. It is concluded that the procedure for using the MC as an effective antioxidant during material initiation into the culture can be applied to the large-scale in vitro propagation of garden strawberries. Moreover, the technology for obtaining the MC from plant waste is environmentally friendly, which is a significant advantage for its use in in vitro technologies.

The effect of 2,4-dichlorophenoxyacetic acid, benzyl amino purin and cupric sulphate on in vitro propagation system from shoot apices of shoot tiller of hybrid Napier grass (Pennisetum purpureum Schum)

An efficient micropropagation method of hybrid Napier grass (Pennisetum purpureumn Schum) for in vitro plant production and material breeding was established from multiple-shoot clumps (MCS) regeneration system. This system was important for forage breeding system. Shoot apices from shoot-tillers produced MSC on Murashige-Skoog (MS) induction medium containing several combinations of BAP and 2,4-D in induction stage. The addition of 5 μM (v/v) and 50 μM (v/v) CuSO4 were added in best medium for inoculation to proliferate the clump in proliferation/multiplication stage. Plant regeneration was achieved by culturing on solid MS with several combination of medium containing NAA and BAP in regeneration stage. The best results for induction were Murashige-Skoog (MS) induction medium containing 2 mgL−1 BAP and 0.1 mgL−1 2,4-D. The proliferation stage on MS medium containing 5 μM CuSÜ4 effective for proliferation (50% multiple shoot formation). The regeneration stage using 0.1 mgL−1 NAA and 2.0 mgL−1 BAP (51.6% number of shoot can regenerate). All plantlets were successfully grown up in an acclimatization stage. Based on the results, the hybrid Napier grass regeneration via MSC was a stable tissue culture system (no albino plats), which could be applied either for further genetic transformation assay or for alternative supply of nursery plant in the future.

Rho Kinase regulates neutrophil NET formation that is involved in UVB-induced skin inflammation.

Objective: Ultraviolet B (UVB) is an important trigger of skin inflammation and lupus with leukocyte recruitment to inflamed skin. We recently reported the involvement of neutrophil NETosis in UVB-induced skin inflammation, and that NETotic nuclear envelope rupture is driven by PKCα-mediated nuclear lamin B disassembly. To address the role of Actin cytoskeleton in NETosis, we investigated the effects of Rho kinase (ROCK) and its downstream actomyosin cytoskeletal networks on PKCα nuclear translocation and NET formation, as well as their involvement in UVB-induced skin inflammation.Methods: We studied the dynamic changes of ROCK and actomyosin cytoskeletal networks during NETosis induction and their involvement in PKCα nuclear translocation. Using mice with hematopoietic-specific ROCK1 deficiency, we investigated the effects of ROCK1 deficiency on NETosis, and its involvement in UVB-induced skin inflammation.Results: Our time course studies demonstrated the dynamic changes of actin polymerization and ROCK activation, support the role of actin cytoskeleton in nuclear translocation of cytosolic PKCα in early stage of NETosis induction. Inhibition of actin polymerization or key molecules of the ROCK/MLCK/myosin pathway decreased PKCα nuclear translocation and NET formation. Genetic deficiency of ROCK1, inhibited NETosis ex vivo and in vivo, decreased extracellular display of NET-associated IL-17A, TNFα, IFNγ, and IFNα in inflamed skin, which were correlated with the ameliorated skin inflammation in UVB-irradiated mice with hematopoietic-specific ROCK1 deficiency.Conclusions: ROCK regulated NETosis through modulation of PKCα nuclear translocation via actomyosin cytoskeletal networks in neutrophils. ROCK1 deficiency ameliorated UVB-induced skin inflammation by attenuation of NETosis and NET-associated cytokines.

Anesthetic and sedative effects of plant-derived essential oils on red swamp crayfish (Procambarus clarkii) at different concentrations and temperatures

Limited studies have been conducted on the use of anesthetic agents during handling, cooking, and transportation of crayfish species. This study was carried out to evaluate the anesthetic effects of clove (Syzygium aromaticum), spearmint (Mentha spicata) and chamomile (Matricaria chamomilla) essential oils on red swamp crayfish (Procambarus clarkii (Girard, 1852)) at temperatures of 17 and 23 °C. The study was performed in 10 L plastic containers filled with 3 L of dechlorinated freshwater to determine induction and recovery times and stages under laboratory conditions. Five concentrations (200, 350, 500, 750, and 1000 µL/L) of essential oils were used. This study found that the induction time at 1000 µL/L was significantly lower than 200 and 350 µL/L at 17 °C (p < 0.05) and there was no statistical difference between the five concentrations at 23 °C (p < 0.05). Recovery at 1000 µL/L was markedly higher than 200, 350, and 500 µL/L at 23 °C (p < 0.05). Red swamp crayfish exposed to clove oil reached Stage 6, which is identified as a total loss of equilibrium, using 1000 µL/L at both temperatures. For spearmint oil, induction time at 1000 µL/L was significantly lower than 200, 350, and 500 µL/L at 17 °C, induction time at 200 µL/L was the highest at 23 °C (p < 0.05), and Stage 5 (partial loss of equilibrium) was recorded as the maximum stage reached. Recovery time at 1000 µL/L was the highest at 17 °C, and recovery at 200 and 300 µL/L were lower than 750 and 1000 µL/L at 23 °C (p < 0.05). No significant differences were recorded in the induction and recovery times of chamomile oil for all the concentrations at both 17 and 23 °C (p > 0.05) and the crayfish reached a maximum of Stage 3 (deep sedation) at 1000 µL/L at 23 °C. Overall, clove and spearmint essential oils were proven to be the most successful at providing effective anesthesia to the red swamp crayfish. However, the length of induction and recovery times may be a disadvantage for some procedures. In addition, it has been revealed that chamomile oil may have only a sedative effect and is therefore unsuitable to be used as an anesthetic.

Историко-философский (объективно-научный) метод юриспруденции С.А. Муромцева

The object of research is the methodological program of Sergey Muromtsev, on the basis of which a program for transforming legal science was developed. The aim of the article is to characterize the formation of Muromtsev's methodology, its sources and composite elements, the impact on the definition of the subject and objectives of legal science and its separation in the industry. Theoretical and methodological attitudes of Muromtsev were formed at the time when the need for reforms was certainly recognized in Russian jurisprudence. The historical and legal basis of the concept was made up of studies on the history and dogma of Roman law. Muromtsev's conception was built on the basis of a critical analysis of the main lines of development of German jurisprudence - Hegelianism, the historical school, taking into account the practical direction and active use of the works of R. Iering. The conception was formed on the basis of the German school of jurisprudence and later supplemented and improved based on the positivist philosophy itself. The transition from “historical-philosophical” to “objective-scientific” research reflected Muromtsev's greater attention to the Anglo-French positivism (in particular, the logic of J. St. Mill). From the point of view of positivist methodology, Muromtsev considered the addition and verification of the results of the historical-comparative study with a priori theses about the nature of man and society, the addition of induction by deduction from psychological and sociological laws. Muromtsev's psychologism was focused primarily on the explanation of the processes of legal education. Muromtsev can be considered a supporter of a multifactorial explanation of the origin of law. However, the immediate (final) source of law, according to his theory, is jurisprudence in the broadest sense of the word (legal thinking). The psychological characteristics of society and lawyers are a factor that determines the specifics of the law in a particular period of a particular society. This conclusion can serve as a guideline in sociological research of the legal education process even today. The distinction between science, politics, and dogma is based on a radical revision of the subject, tasks (goals), and methodology of jurisprudence from the standpoint of positivism and historicism. As a result, Muromtsev proposed to distinguish between dogma in the strict sense (study of current law in order to apply it in practice) and a new general dogmatic theory (“a systematic presentation of the principles of the current law of any country and any time”). It is not a study of laws in the scientific sense of the word, but it can be a preparatory stage for induction and deduction, which should be done by jurisprudence as a part of social science. The merit of Muromtsev is not the “invention” of new methodological techniques, but a consistent application of the positivist methodology to the study of legal material.

MBD protein recognizes flower control genes regulated by DNA methylation in &lt;i&gt;Chrysanthemum lavandulifolium&lt;/i&gt;

Dynamic changes in DNA methylation regulate the expression of genes and play important roles especially in the flowering processes of higher plants. Methyl-CpG-binding domain protein could specifically recognize hypermethylated regions in the genome, thus MBD sequencing technology and CpG islands analysis of the sequences were used to identify candidate genes that were regulated by DNA methylation, in particular the flowering induction stage of <em>Chrysanthemum lavandulifolium</em>. MBD-seq identified 89 candidate genes which included 49 genes exhibiting changes in DNA methylation status during floral induction. Based on CpG islands analysis of the sequences, 27 candidate genes were selected that may be regulated by DNA methylation. The expression levels of 30 candidate genes and nine key genes were determined by RT-PCR and qRT-PCR during floral induction (7D), four genes (<em>ClFT</em>, <em>ClMET</em>, <em>DFL</em> and <em>ClWRKY21</em>) were similarly up-regulated. Methylation-specific PCR analysis also indicated that there were changes in the DNA methylation status in the <em>DFL</em> and <em>ClWRKY21</em>. The changes in the DNA methylation status during the induction phase of flowering may lead to changes in gene expression. In this study, a set of genes were identified that are proposed to be involved in floral induction and two key genes were identified (<em>DFL, ClWRKY21</em>) that were regulated by DNA methylation during the flowering process of <em>C. lavandulifolium</em>.

Fundamentals of the catalytic conversion of methanol to hydrocarbons

For more than four decades, the methanol-to-hydrocarbons (MTH) reaction has been a successful route to producing valuable fuels and chemicals from non-petroleum feedstocks. This review provides the most comprehensive summary to date of recent research concerning the mechanistic fundamentals of this important reaction, covering different reaction stages. Mechanisms that have been proposed to explain the initial C-C bond formation during the induction stage of the MTH reaction are introduced, including the methoxymethyl cation, Koch carbonylation, carbene and methane-formaldehyde processes. At present, there is no consensus regarding these hypothetical mechanisms as a consequence of the limited amount of conclusive experimental evidence. The steady state of the MTH reaction is also examined with a focus on the widely accepted indirect hydrocarbon pool mechanism and the dual cycle concept that provides a mechanistic basis for the effects of zeolite structures and reaction conditions on product distribution. In the following section, advanced characterization techniques capable of providing new insights into the formation of coke species during the MTH reaction and innovative approaches effectively inhibiting coke formation are introduced. Finally, a summary is provided and perspectives on current challenges and the future development of this area are presented.

Efficacy and safety of adding gemtuzumab ozogamicin to conventional chemotherapy for adult acute myeloid leukemia: a systematic review and meta-analysis

ABSTRACT Introduction: Compared with the 3 + 7 regimen, the addition of gemtuzumab ozogamicin (GO) has improved survival in patients with acute myeloid leukemia (AML). We conducted a systematic review and meta-analysis to examine the overall efficacy and safety of GO in combination with conventional chemotherapy regimens in patients with AML. Methods: We searched several databases (MEDLINE, Embase, Web of Science and Cochrane Library). Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated for overall survival (OS) and relapse-free survival (RFS); odds ratios (ORs) with 95% CIs were calculated for the other outcomes. Results: Ten records involving 11 randomized controlled trials (RCTs) met the inclusion criteria. GO plus induction chemotherapy significantly increased RFS (HR: 0.84, 95% CI: 0.73–0.98), decreased the incidence of relapse (OR: 0.78, 95% CI: 0.68–0.91) and resistant disease (OR: 0.72, 95% CI: 0.61–0.84), and had no significant effect on the rate of complete remission (CR) with or without incomplete platelet recovery (OR: 1.21, 95% CI: 0.94–1.55), 30-day mortality (OR: 1.25, 95% CI: 0.99–1.57). Subgroup analysis showed significant OS benefits for patients with favorable cytogenetic (HR: 0.50, 95% CI: 0.28–0.89) or given GO at induction stage (HR: 0.91, 95% CI: 0.84–1.00). Compared with other dosing schedule groups, 3 mg/m2 fractionated schedule had a greater RFS benefit (HR: 0.52, 95% CI: 0.36–0.76) and lower relapse risk (OR: 0.48, 95% CI: 0.28–0.84). Conclusions: Adding low-dose GO to induction or both induction and post-remission chemotherapy has considerable efficacy and unequivocal safety for newly diagnosed adult AML.

Analysis of the PEBP gene family and identification of a novel FLOWERING LOCUS T orthologue in sugarcane.

Sugarcane (Saccharum spp.) is an important economic crop for both sugar and biomass, the yields of which are negatively affected by flowering. The molecular mechanisms controlling flowering in sugarcane are nevertheless poorly understood. RNA-seq data analysis and database searches have enabled a comprehensive description of the PEBP gene family in sugarcane. It is shown to consist of at least 13 FLOWERING LOCUS T (FT)-like genes, two MOTHER OF FT AND TFL (MFT)-like genes, and four TERMINAL FLOWER (TFL)-like genes. As expected, these genes all show very high homology to their corresponding genes in Sorghum, and also to FT-like, MFT-like, and TFL-like genes in maize, rice, and Arabidopsis. Functional analysis in Arabidopsis showed that the sugarcane ScFT3 gene can rescue the late flowering phenotype of the Arabidopsis ft-10 mutant, whereas ScFT5 cannot. High expression levels of ScFT3 in leaves of short day-induced sugarcane plants coincided with initial stages of floral induction in the shoot apical meristem as shown by histological analysis of meristem dissections. This suggests that ScFT3 is likely to play a role in floral induction in sugarcane; however, other sugarcane FT-like genes may also be involved in the flowering process.

Intranasal oxytocin may improve odds of abstinence in cocaine-dependent patients: results from a preliminary study

BackgroundOxytocin (OT) treatment in drug addiction studies have suggested potential therapeutic benefits. There is a paucity of clinical trial studies of oxytocin in cocaine use disorders. MethodThis was a 6-week randomized, double-blind, outpatient clinical trial study investigating the effect of daily Intranasal Oxytocin (24 IU) on cocaine use by cocaine use disorder patients. After a 7-day inpatient abstinence induction stage, patients were randomized to intranasal oxytocin or intranasal placebo. During the outpatient phase, cocaine use disorder patients were required to present themselves to the research staff 3 times a week for witnessed randomized medication administration, to provide a urine sample for qualitative toxicology, and complete mandatory assessments, including the Time-Line-Follow Back. For the interim days, patients were given an “at-home” bottle that was weighed at each clinic visit to monitor compliance. ResultsNeither administration of Intranasal placebo (n = 11) or Oxytocin (n = 15) induced at least 3 weeks of continuous abstinence. However, from week 3, the odds of weekly abstinence increased from 4.61 (95% CI = 1.05, 20.3) to 15.0 (CI = 1.18, 190.2) by week 6 for the Intranasal Oxytocin group (t = 2.12, p = 0.037), though there was no significant group difference overall in the odds of abstinence over time (F1,69 = 1.73, p = 0.19). More patients on Intranasal Oxytocin dropped out (p = 0.0005). ConclusionsIntranasal Oxytocin increased the odds of weekly abstinence in Cocaine patients after 2 weeks compared to PBO, but was associated with a higher dropout rate. (ClinicalTrials.gov 02,255,357, 10/2014)

Nefritis lúpica Experiencia con dosis reducidas de glucocorticoides en una unidad de enfermedades autoinmunes sistémicas

Introduction: current recommendations for the treatment of lupus nephritis (LN) point to glucocorticoid doses lower to achieve disease control and prevent accumulated damage.Objective: to know and compare the response to treatment of patients with proliferative LN in its induction stage with two Prednisone treatment regimens (PDN): reduced initial doses &lt;30 mg / d and standard initial doses&gt; 30 mg / d.Method: clinical, analytical and therapeutic variables of patients with proliferative LN categorized in two were compared groups according to standard or reduced prednisone starting dose (PDNi).Results: 21 patients with proliferative LN were studied (n = 12 reduced PDNi vs. n = 9 standard PDNi). There were no significant differences in the clinical and analytical variables. A statistically significant difference was observed in the number of methylprednisolone pulses (5 ± 2.95 PDNi &lt;30 mg / d vs 2.33 ± 2.91 PDNi&gt; 30 mg / d, p = 0.041) and in the dose of prednisone accumulated at 6 months (12.8 mg ± 4.9 PDNi &lt;30 mg / d vs 30.0 ± 13.1 mg PDNi&gt; 30 mg / d, p = 0.008). There were no differences significant in the proportion of patients who achieved the complete response, in the time to reach it or in the adverse effects between both groups.Conclusions: the therapeutic scheme of the PDNi group &lt;30 mg / d was associated with a lower accumulated dose of prednisone and a response to comparable treatment, which suggests less accumulated damage related to the use of glucocorticoids.

Experiment on hydration exothermic characteristics and hydration mechanism of sand-based cemented paste backfill materials

Cemented paste backfill technology can effectively control overburden movement, protect surface buildings and ecological environment. In this study, the early hydration exothermal characteristics, compressive strength evolution and hydration mechanism of sand-based cemented paste backfill materials (SCPB) were studied by hydration heat tests, uniaxial compressive strength tests, x-ray diffraction, scanning electron microscope and energy dispersive spectrometer tests; the hydration model of SCPB and fly ash were also constructed. The results show that: (1) the early hydration exothermic process of the SCPB can be divided into five stages: Dissolution stage, Induction stage, Acceleration stage, Deceleration stage and Slow deceleration stage. The heat release rates in the five stages are 5.64, 2.09, 3.63, 3.16 and 1.07 J·(g·h)-1, respectively; (2) the mechanical strength and elastic modulus of the SCPB increase with the increase of curing age; when the curing age of 7 d, the elastic modulus of the SCPB reaches 67.92% of the final value; (3) the primary hydration products of the SCPB are calcium silicate hydrate, ettringite, calcium hydroxide, Calcium carbonate and Calcium aluminate hydrate; (4) the hydration process of the SCPB can be divided into Dissolution stage, Hydration stage and Hardening stage, and the hydration process of fly ash experienced Adsorption stage and Hydration stage.

Lack of plastid-encoded Ycf10, a homolog of the nuclear-encoded DLDG1 and the cyanobacterial PxcA, enhances the induction of non-photochemical quenching in tobacco.

pH homeostasis in the chloroplast is crucial for the control of photosynthesis and other metabolic processes in plants. Recently, nuclear‐encoded Day‐Length‐dependent Delayed Greening1 (DLDG1) and Fluctuating‐Light Acclimation Protein1 (FLAP1) that are required for the light‐inducible optimization of plastidial pH in Arabidopsis thaliana were identified. DLDG1 and FLAP1 homologs are specifically conserved in oxygenic phototrophs, and a DLDG1 homolog, Ycf10, is encoded in the chloroplast genome in plant cells. However, the function of Ycf10 and its physiological significance are unknown. To address this, we constructed ycf10 tobacco Nicotiana tabacum mutants and characterized their phenotypes. The ycf10 tobacco mutants grown under continuous‐light conditions showed a pale‐green phenotype only in developing leaves, and it was suppressed in short‐day conditions. The ycf10 mutants also induced excessive non‐photochemical quenching (NPQ) compared with those in the wild‐type at the induction stage of photosynthesis. These phenotypes resemble those of Arabidopsis dldg1 mutants, suggesting that they have similar functions. However, there are distinct differences between the two mutant phenotypes: The highly induced NPQ in tobacco ycf10 and the Arabidopsis dldg1 mutants are diminished and enhanced, respectively, with increasing duration of the fluctuating actinic‐light illumination. Ycf10 and DLDG1 were previously shown to localize in chloroplast envelope‐membranes, suggesting that Ycf10 and DLDG1 differentially control H+ exchange across these membranes in a light‐dependent manner to control photosynthesis.

Cryptochrome 2 from Lilium × formolongi Regulates Photoperiodic Flowering in Transgenic Arabidopsis thaliana

The photoperiodic flowering pathway is essential for plant reproduction. As blue and ultraviolet-A light receptors, cryptochromes play an important role in the photoperiodic regulation of flowering. Lilium × formolongi is an important cut flower that flowers within a year after seed propagation. Floral induction is highly sensitive to photoperiod. In this study, we isolated the CRYPTOCHROME2 gene (LfCRY2) from L. × formolongi. The predicted LfCRY2 protein was highly homologous to other CRY2 proteins. The transcription of LfCRY2 was induced by blue light. LfCRY2 exhibits its highest diurnal expression during the floral induction stage under both long-day and short-day photoperiods. Overexpression of LfCRY2 in Arabidopsis thaliana promoted flowering under long days but not short days, and inhibited hypocotyl elongation under blue light. Furthermore, LfCRY2 was located in the nucleus and could interact with L. × formolongi CONSTANS-like 9 (LfCOL9) and A. thaliana CRY-interacting basic-helix-loop-helix 1 (AtCIB1) in both yeast and onion cells, which supports the hypothesis that LfCRY2 hastens the floral transition via the CIB1-CO pathway in a manner similar to AtCRY2. These results provide evidence that LfCRY2 plays a vital role in promoting flowering under long days in L. × formolongi.

Abstract 13848: Establishing an Optogenetic in vitro Model to Study Atrial Fibrillation Based on Human Engineered Heart Tissue

Introduction: Atrial fibrillation (AF) is a type of sustained cardiac tachyarrhythmia in which the atrial rate can reach up to 300-600 beats per minute (BPM). The elucidation of the mechanisms of AF and the search for new therapeutic methods is hampered by a lack of suitable in vitro models. In previous studies, chronic optical tachypacing induced arrhythmia vulnerability in ventricular-like human engineered heart tissue (EHT). Here, we aimed to optimize an AF in vitro model based on optogenetics, EHT and a novel optogenetic pacing platform. Methods: Human induced pluripotent stem cells (hiPSC) stably expressing Volvox-Channelrhodopsin-1 (VChR1) were differentiated into atrial-like cardiomyocytes (CM) by treatment with 1 μM retinoic acid (RA) at the cardiac induction stage. CMs were used to cast fibrin-based 24-well format EHTs. The expression of atrial/ventricular markers was validated by qPCR, and action potential (AP) recordings with atrial-specific channel inhibitors were performed on at least one-month-old EHTs. A novel custom-designed circuit board with a programmable microcontroller and 24 RGB addressable light-emitting diodes (LED) was used for optical tachypacing. 25-30 days old EHTs were stimulated by 90 s bursts of blue light pulses (5 Hz), separated by 10 s breaks for 35-40 days. Non-paced and paced EHTs were characterized regarding contractility and gene expression. Results: EHTs had a high expression of atrial mRNA markers and displayed atrial-like AP. A flexible and straightforward optogenetic tool was built to make chronic tachypacing feasible. Using this novel platform, EHTs were successfully paced at 5 Hz for up to 40 days. Compared with non-paced EHTs, paced EHTs showed a different spontaneous contractility profile, higher expression of stress genes, and released more troponin I into the medium. Conclusions: We have successfully generated an in vitro model to mimic the status of atria with a high frequency (300 BPM) during AF. Paced EHTs displayed stress signs, partially resembling the changes of atria in AF. In the future, we could utilize this model to study the underlying mechanisms and assess proarrhythmic and antiarrhythmic drug effects.

Results of comprehensive treatment of locally advanced oral cancer using regional intra-arterial chemotherapy

Introduction. Head and neck cancers are a significant healthcare and social problem worldwide with an estimated 377,713 new cases and 177,757 deaths registered annually. The incidence of head and neck cancer in Russia is 4.12 per 100,000. Despite all the achievements of current oncology, approximately 50–60 % of patients with locally advanced head and neck cancer develop relapses within the first 2 years after treatment completion.The study objective is to analyze the effectiveness of regional intra-arterial polychemotherapy in the combined and comprehensive treatment of locally advanced oral cancer.Materials and methods. This prospective study included 29 patients with oral squamous cell carcinoma treated and followed-up at N.N. Blokhin National Cancer Research Center between 2017 and 2020. The majority of patients (82.8 %) had stage III–IV disease. We evaluated clinical response to neoadjuvant regional intra-arterial chemotherapy, pathomorphosis of the primary tumor after surgery, treatment toxicity, overall survival, and relapse-free survival.Results. The objective response rate assessed for the primary oral tumor after regional intra-arterial chemotherapy was 100 %; complete regression of the primary tumor was achieved in 82.8 % of patients. More than one-third of participants (35.5 %) had complete regression of metastases in regional lymph nodes. In 73.5 % of patients who had under gone neoadjuvant regional intra-arterial chemotherapy followed by surgery, we observed grade IV therapeutic pathomorphosis of the primary tumor. The 2-year relapse-free survival rate was 100 % in individuals with stage II–III disease and 92.9 ± 6.9 % in patients with stage IV disease.Conclusion. The administration of regional intra-arterial chemotherapy as an induction stage ensures high treatment efficacy and high rate of complete pathomorphological responses. This suggests the opportunity of conservative treatment for patients with locally advanced oral cancer, which is currently considered impossible for such patients. Moreover, this method demonstrated moderate systemic toxicity, which expands the indications for its use and increase treatment compliance.

THE EFFECT OF CULTURE MEDIA TYPE AND PLANT GROWTH REGULATORS ON CALLUS INDUCTION OF OIL PALM (Elaeis guineensis Jacq) PISIFERA TYPE

Oil palm has a high economic value since it is one of the highest vegetable oil-producing plants compared to other oil-producing plants. The provision of good planting material for oil palm plantations is one of the determining factors to increase productivity. The parent Pisifera type of oil palm is important to develop the high-yielding oil palm Tenera varieties. The provision of oil palm material could be done through generative system with seeds and also could be done through vegetative approaches using tissue culture techniques. It aims to get plants that are genetically the same as their parents (true to type). The purpose of this study was to see the effect of different type of tissue culture media and plant growth regulators (PGR’s) on the callus induction stage of Pisifera type oil palm. The results show that the treatment using Murasige and Skoog (MS) culture media is able to give a better effect when compared to the use of Eeuwens and Blake (Y3) basic media. While the use of PGR treatment (H6 = NAA 6 mg/l + 2.4-D 0.5 mg/l) showed a callus growth percentage of 76%, which was better than (H1 = Kin 0.1 mg/l + 2.4-D 100 mg/l) by 42%.

Auto/paracrine factors and early Wnt inhibition promote cardiomyocyte differentiation from human induced pluripotent stem cells at initial low cell density

Cardiomyocytes derived from human induced pluripotent stem cells (hiPSCs) have received increasing attention for their clinical use. Many protocols induce cardiomyocytes at an initial high cell density (confluence) to utilize cell density effects as hidden factors for cardiomyocyte differentiation. Previously, we established a protocol to induce hiPSC differentiation into cardiomyocytes using a defined culture medium and an initial low cell density (1% confluence) to minimize the hidden factors. Here, we investigated the key factors promoting cardiomyocyte differentiation at an initial low cell density to clarify the effects of cell density. Co-culture of hiPSCs at an initial low cell density with those at an initial high cell density showed that signals secreted from cells (auto/paracrine factors) and not cell–cell contact signals, played an important role in cardiomyocyte differentiation. Moreover, although cultures with initial low cell density showed higher expression of anti-cardiac mesoderm genes, earlier treatment with a Wnt production inhibitor efficiently suppressed the anti-cardiac mesoderm gene expression and promoted cardiomyocyte differentiation by up to 80% at an initial low cell density. These results suggest that the main effect of cell density on cardiomyocyte differentiation is inhibition of Wnt signaling at the early stage of induction, through auto/paracrine factors.