Ultraviolet Irradiation Treatment Research Articles

Fabrication of continuous glass fiber-reinforced dual-cure epoxy composites via UV-assisted fused deposition modeling

This paper proposes an ultraviolet (UV)-assisted fused deposition modeling (FDM) method with a dual-curing process for fabricating continuous fiber-reinforced thermosetting polymer composites (CFRTPCs). The entire approach is based on the additive deposition of fused continuous glass fiber (CGF)/epoxy (EP) filaments, which are rapidly cooled upon exiting the printer nozzle to form a solid three-dimensional (3D) object. At the same time, UV irradiation is used to activate the photoinitiator and photosensitizer to pre-cure the extruded material. The final polymerization and crosslinking reactions are achieved using a post heat treatment. Herein, the UV absorption characteristics and post heating process of the dual-cure EP matrix were investigated to demonstrate the feasibility and generality of the proposed technique. Finally, 3D printed CGF/EP samples with a 43 ± 3 wt% fiber content exhibited a tensile strength and tensile modulus of 272.51 ± 5.12 MPa and 8.01 ± 0.45 GPa, respectively; flexural strength and flexural modulus of 299.36 ± 6.16 MPa and 8.35 ± 0.18 GPa, respectively; and interlaminar shear strength of 34.06 ± 0.83 MPa. The combination of UV irradiation and post heat treatment offers a rapid, feasible, and effective dual-cure solution for 3D printing of CFRTPCs, which could be a reliable fabrication method for the development of thermosetting composite systems used in various applications.

Effects of Different Stress Treatments on the Total Terpene Trilactone Content and Expression Levels of Key Genes in Ginkgo biloba Leaves

As unique secondary metabolites of Ginkgo biloba L. and relics of Ginkgoaceae, terpene trilactones (TTLs) possess great medicinal value. In this study, we investigated the effects of ultraviolet (UV) irradiation, cold stress (4 °C), and exogenous hormone treatment on TTLs and key genes expression in ginkgo leaves in annual potted ginkgo seedlings subjected to different stress treatments. The processing conditions were as follows: UV treatment (1500 μJ/m2) for 0, 8, 16, 24, and 48 h; cold stress at 4 °C, 400 µmol photons m−2 s−1; 100 μM abscisic acid (ABA); 100 μM methyl jasmonate (MeJA); 10 mM salicylic acid (SA); and 10 mM ethephon (ETH) treatments for 0, 2, 4, 6, and 8 days. Results of evaporative light-scattering detector–high-performance liquid chromatography showed that UV, cold stress, ABA, SA, MeJA, and ETH treatments increased the TTL content at various levels and up to 21.9%. The relationships among the expression levels of the key enzyme genes GbDXS, GbGGPPS, GbLPS, and GbMVD in the TTL biosynthesis pathway were also analyzed. Changes in the TTL content and expression levels of the key genes were significantly and positively correlated with TTL content. UV, cold stress, ABA, SA, MeJA, and ETH were found to increase the TTL content by upregulating the expression of the key genes. This study aimed to reveal the molecular mechanism through which TTLs are synthesized. The results can also provide theoretical guidance for the application of treatment methods to increase TTL content.

Costs and compensation in zooplankton pigmentation under countervailing threats of ultraviolet radiation and predation

Evolutionary responses to opposing directions of natural selection include trade-offs, where the phenotype balances selective forces, and compensation, where other traits reduce the impact of one selective force. Zooplankton pigmentation protects from ultraviolet radiation (UVR) but attracts visual predators. This trade-off is understudied in the ocean where planktonic larvae in surface waters face ubiquitous UVR and visual predation threats. We tested whether crab larvae can behaviorally reduce UVR risk through downward swimming or expansion of photoprotective chromatophores. Then we examined whether more pigmented larvae are more heavily predated by silverside fish under natural sunlight in the tropics in three UVR treatments (visible light, visible + UVA, visible + UVA + UVB). Lastly, we tested the behavioral chromatophore response of larvae to predation threats in two light treatments. Armases ricordi avoided surface waters after exposure to sunlight with UVR. Armases ricordi, Armases americanum, and Eurypanopeus sp. consistently expanded chromatophores in UVR or visible light, while Mithraculus sculptus and Mithraculus coryphe showed no response. Fish preferred pigmented larvae on sunnier days in visible light lacking UVR. Lastly, both M. coryphe and M. sculptus unexpectedly expanded chromatophores in fish cues, but responses were inconsistent over trials and across light treatments. The more consistent larval responses to UVR than to predator cues and the lack of predator preferences in natural light conditions suggest that UVR may have a stronger influence on pigmentation than predation. This study improves our understanding of planktonic adaptation to countervailing selection caused by visual predation and exposure to UVR.

Light Shock Stress after Outdoor Sunlight Exposure in Seedlings of Picea abies (L.) Karst. and Pinus sylvestris L. Pre-Cultivated under LEDs—Possible Mitigation Treatments and Their Energy Consumption

Year-round cultivation under light emitting diodes (LEDs) has gained interest in boreal forest regions like Fenno-Scandinavia. This concept offers forest nurseries an option to increase seedling production normally restricted by the short vegetation period and the climate conditions. In contrast to some horticultural crops which can be cultivated entirely under LEDs without sunlight, forest seedlings need to be transplanted outdoors in the nursery at a very young age before being outplanted in the field. Juvenile plants are less efficient using absorbed light and dissipating excess energy making them prone to photoinhibition at conditions that usually do not harm mature plants. The outdoor transfer can cause stress in the seedlings due to high sunlight intensity and exposure to ultraviolet (UV) radiation not typically present in the spectra of LED lamps. This study tested possible treatments for mitigating light shock stress in seedlings of Picea abies (L.) Karst. and Pinus sylvestris L. transplanted from indoor cultivation under LEDs to outdoor sunlight exposure. Three sowings were carried out in 2014 (May and June) and 2015 (May) cultivating the seedlings during five weeks under LED lights only. Afterwards, higher light intensity or UV radiation treatments were applied during one week in order to adapt the seedlings to natural outdoor conditions. After transplanting a transition phase was introduced using shading cloths for one or three weeks as outdoor treatments for light shock mitigation. Chlorophyll fluorescence (ChlF) levels and CO2 assimilation rates were measured before transplanting and followed outdoors during 5 weeks. The ChlF results revealed stress symptoms in the photoreceptors during the first days after transplanting. After five weeks outdoors the ChlF levels had recovered and the light saturation points had shifted, allowing higher CO2 assimilation rates. By the end of the vegetation period the morphological attributes showed no major differences between treatments.

Roles of phase transition and surface property evolution in nanotribological behaviors of H-DLC: Effects of thermal and UV irradiation treatments

Hydrogenated diamond-like carbon (H-DLC) films that behave super-low friction in vacuum are effective lubricants for aerospace moving parts; however, their tribological properties strongly depend on space environments. In this study, the transition of substrate phase and the evolution of outermost surface properties caused by simulated space conditions, involving thermal treatments and ultraviolet (UV) irradiation, were investigated; their effects on the tribological behaviors of H-DLC films were qualified at nanoscale by controlling the interface deformation and substrate wear at single-asperity contact using atomic force microscopy (AFM). Although thermal treatments in vacuum cannot change the outermost surface properties, they can induce the phase transition of H-DLC substrates above a critical temperature, which results in the degradation of tribological performance. UV irradiation in moist air varies the material phase of surfacial layer accompanied by surface oxidation, which not only increases the nanowear and wear-related friction but also enhances the wearless-related interfacial adhesion and friction interactions. Results of this study can provide new insight into the mechanism of space environments affecting the tribological reliability of H-DLC and help for developing a new coating for minimizing interfacial interaction and surface damage in space applications.

An Ultraviolet‐Deposited MoO3 Film as Anode Interlayer for High‐Performance Polymer Solar Cells

AbstractAn ultraviolet‐deposited MoO3 film is developed as anode interlayer based on molybdenum(V) chloride as precursor. The ultraviolet‐deposited MoO3 film is prepared from the precursor film (spin coated from its solution) with ultraviolet irradiation treatment, and the preparation process of the MoO3 film is facile, low cost, and compatible with mass production and flexible substrate. The composition of the MoO3 film is analyzed by X‐ray photoelectron spectroscopy. The work function as well as the surface morphology and wettability of indium tin oxide (ITO) modified by the MoO3 film are investigated by ultraviolet photoelectron spectroscopy, atomic force microscopy, and contact angle tester, respectively, where the analyses show the ITO modified by the MoO3 anode interlayer can offer excellent energy level alignment and interface contact with active layer. The photovoltaic performance of nonfullerene polymer solar cells (PSCs) based on the MoO3 anode interlayer is researched with typical and relatively low‐cost PBDB‐T:ITIC as active layer, and the ITO/MoO3‐based device shows the highest power conversion efficiency of 9.27% compared with the bare ITO‐based device (3.69%) and the ITO/PEDOT:PSS‐based device (9.15%). The results demonstrate the great potential of the ultraviolet‐deposited MoO3 film as anode interlayer for high‐performance PSCs.

Improvement in Bias Stability of IGZO TFT With Etching Stop Structure by UV Irradiation Treatment of Active Layer Island

In this paper, the effect of ultraviolet (UV) irradiation treatment of active layer IGZO on the bias stability of amorphous IGZO thin film transistor with etch stop (ES) structure is studied. Along with the increase in UV irradiation time, the surface of the IGZO film becomes smoother. An appropriate UV irradiation treatment cannot only improve the bias stress stability but also suppress the lump behavior generated by light illumination. The devices with irradiation time of 1 min exhibits an excellent properties with the field effect mobility of 15.07 cm2/V·s, subthreshold swing of 0.2 V/dec, and all bias stress less than 0.2 V including NIBS and PIBS. However, a relative long UV treatment would result in deteriorating the bias stability of devices. The fact implies that the reasonable UV irradiation treatment on the active layer island before depositing the ES layer is advantageous for improving the stability of the a-IGZO TFT device.

Ultraviolet (UV) Activation Effect on Antibacterial Agents of Red Betel (Piper Crocatum) Extract to Streptococcus mutans

Ultraviolet (UV) radiation has caused negative effect on biological environment. As non–moving living things, plants have their own response to reduce the negative effect by increasing flavonoid accumulation, such as red betel (Piper crocatum), which help the plant’s protection from bacteria. In Indonesia, red betel has been used as a herb treatment, especially in oral treatment. This study aims to optimise the antibacterial effect of red betel extract on oral bacteria, Streptococcus mutans, by irradiating UV. Kirby-Bauer method of disk diffusion test was used on this study by showing the bacteria’s diameter of inhibition zone. The samples distribution was devided into two groups, group (L–R+), control group, only used red betel extract without UV irradiation and group (L+R+) treatment combination of UV irradiation and red betel extract. The results showed that group L+R+ had better antibacterial effect on Streptococcus mutans, proven by the bigger inhibition zone, than group L–R+. UV irradiation for 12 hours showed the best result on each treatment with diameter of inhibition zone (15.00 ± 0.05) mm for 10 watt and (15.96 ± 0.05) mm for 15 watt. So, it is proven that UV irradiation can increase the antibacterial effect of red betel extract.

Computational search for UV radiation resistance strategies in Deinococcus swuensis isolated from Paramo ecosystems.

Ultraviolet radiation (UVR) is widely known as deleterious for many organisms since it can cause damage to biomolecules either directly or indirectly via the formation of reactive oxygen species. The goal of this study was to analyze the capacity of high-mountain Espeletia hartwegiana plant phyllosphere microorganisms to survive UVR and to identify genes related to resistance strategies. A strain of Deinococcus swuensis showed a high survival rate of up to 60% after UVR treatment at 800J/m2 and was used for differential expression analysis using RNA-seq after exposing cells to 400J/m2 of UVR (with >95% survival rate). Differentially expressed genes were identified using the R-Bioconductor package NOISeq and compared with other reported resistance strategies reported for this genus. Genes identified as being overexpressed included transcriptional regulators and genes involved in protection against damage by UVR. Non-coding (nc)RNAs were also differentially expressed, some of which have not been previously implicated. This study characterized the immediate radiation response of D. swuensis and indicates the involvement of ncRNAs in the adaptation to extreme environmental conditions.

Emerging Nonsteroid-Based Procedural Therapies for Alopecia Areata: A Systematic Review.

Alopecia areata (AA) is a common form of patchy, nonscarring hair loss. Although intralesional steroid injections are currently the mainstay procedural therapy for AA, other nonsteroid-based procedural therapies, including platelet-rich plasma (PRP), ultraviolet radiation (UVR), and laser-based modalities, are emerging as practical options. To systematically review nonsteroid-based procedural therapies for AA and recapitulate the available clinical data. A systematic review of the literature was performed searching PubMed/MEDLINE databases identifying studies investigating PRP, UVR, and laser-based modalities for AA treatment. Literature search yielded 644 articles encompassing PRP, UVR, and laser treatment modalities for AA. Of the 644 articles, 46 met inclusion criteria. Although numerous reports demonstrate strong potential for PRP, UVR, and laser modalities in treating AA, high-quality evidence supporting their efficacy is still lacking. There is an abundance of evidence for nonsteroid-based procedural therapies in the treatment of AA. Randomized control trials comparing these treatment options head-to-head should be performed to better understand the true efficacy of these treatments.

Differential Responses of Human Dendritic Cells to Live or Inactivated Staphylococcus aureus: Impact on Cytokine Production and T Helper Expansion.

Understanding Staphylococcus aureus (S. aureus)–host immune system interaction is crucial to meet the tremendous medical need associated with this life-threatening bacterial infection. Given the crucial role of dendritic cells (DC) in dictating immune responses upon microbial challenge, we investigated how the bacterial viability and the conservation of structural integrity influence the response of human DC to S. aureus. To this end, human primary DC were stimulated with the methicillin-resistant S. aureus USA300 live strain, USA300 inactivated by heat (HI), ultraviolet irradiation (UVI), or paraformaldehyde treatment (PFAI) and subsequently analyzed for cell phenotype and immune-modulatory properties. Although no differences in terms of DC viability and maturation were observed when DC were stimulated with live or inactivated bacteria, the production of IL-12, IL-23, and other cytokines differed significantly. The Th1 and Th17 expansion was also more pronounced in response to live vs. inactivated S. aureus. Interestingly, cytokine production in DC treated with live and inactivated USA300 required phagocytosis, whereas blocking endosomal Toll-like receptor signaling mainly reduced the cytokine release by live and HI USA300. A further analysis of IFN-β signaling revealed the induction of a cyclic GMP-AMP synthase stimulator of interferon genes (cGAS-STING)-independent and IRF3-dependent signaling pathway(s) in UVI-stimulated DC. This study underscores the capacity of human DC to discriminate between live and inactivated S. aureus and, further, indicates that DC may represent a valuable experimental setting to test different inactivation methods with regard to the retention of S. aureus immunoregulatory properties. These and further insights may be useful for the development of novel therapeutic and prophylactic anti-S. aureus vaccine strategies.

Interactive Effects of Ultraviolet Radiation and Dissolved Organic Carbon on Phytoplankton Growth and Photosynthesis in Sanya Bay, Northern South China Sea

The effects of a simulated climate change scenario, i.e., increased ultraviolet radiation (UVR) and dissolved organic carbon (DOC), on the growth and photosynthesis of tropical coastal phytoplankton were evaluated in Sanya Bay, northern South China Sea, in summer. Microcosm experiments were conducted at two contrasting stations (Stns S1 and S2) with three different UVR treatments and two DOC addition treatments. Our results showed that natural sunlight UVR or increased UV-B did not affect phytoplankton biomass and primary production. However, increased UV-B significantly decreased the proportion of picophytoplankton and the efficiency of carbon fixation at Stn S2. DOC enhancement caused negative effects on primary production under natural sunlight UVR only at Stn S1. Interactive effects of UVR and DOC addition on phytoplankton biomass and primary production were detected at Stn S1, due to the negative effects of DOC being eliminated under the increased UV-B condition. The lack of interactive effects at Stn S2 were likely due to the differences with Stn S1 in terms of light acclimation and biological interaction. In summary, this future climate change scenario will probably not affect the photosynthetic CO2 fixation and biomass of natural phytoplankton in Sanya Bay.

ERIC-PCR technique applied to monitoring and quantification of DNA damage during water disinfection process

In this work, we propose a novel application of ERIC-PCR technique to study DNA damage after ultraviolet radiation (UV) and peracetic acid (PAA) treatment for water disinfection purpose. The efficacy of both treatments on E. coli suspension was evaluated by two approaches: through monitoring of inactivation by conventional culture technique, and by analyzing DNA damage with ERIC-PCR. All the experiments were carried out in a batch reactor, using three intensities of UV-C radiation (10.5, 4.2 and 2.1 mW/cm2) and different PAA concentrations (4 to 16 ppm). Both treatments produced bacterial inactivation in a dose-response fashion. Based on the results of bacterial count we obtained an index of inactivation (INACI). For each sample, DNA extraction was performed and evaluated by ERIC-PCR. Qualitative modifications were observed in ERIC-PCR band patterns for all the UV-C radiation intensities used, but no changes were detected at any of the PAA concentrations. The banding pattern modifications observed are consequence of the interruption of Taq polymerase enzyme amplification-activity, caused by the presence of alterations on the DNA structure (dimer and hydrates formation). Furthermore, an index was proposed to measure DNA damage (DNADI) regarding the changes in the relative optical density values of the amplification products. A linear correlation was obtained with a high correspondence between the inactivation index (INACI) and the DNA damage index (DNADI), that was expressed as DNADI = 0.05881×INACI. This approach proves that ERIC-PCR is a feasible and valuable tool for detecting and quantifying DNA damage and it may provide a useful strategy for bacterial identification, tracking changes in DNA and providing reliable and reproducible data.

Evaluation of Continuous UVC Treatments and its Combination with UHPH on Spores of Bacillus subtilis in Whole and Skim Milk.

The aim of this study was to evaluate the effectiveness of different UVC treatments, alone or in combination with ultra-high pressure homogenization (UHPH) on Bacillus subtilis spores in milk. Spores of B. subtilis (CECT4002) were inoculated in whole and skim milk to an initial concentration about 6 log CFU/mL. Milk was subjected to different ultraviolet radiation treatments at 254 nm (UVC) using a concentric tubular reactor in a dose ranging from 10 to 160 J/mL. Different number of passes were used to adjust the final dose received by the matrix. In general, increasing the number of passes (defined as number of entries to the tunnel-NET) increased the inactivation of spores of B. subtilis. The best lethality results (above 4 Log CFU/mL) were obtained by applying doses from 100 J/mL with several NET. When the same doses were achieved with a single pass lethality in most cases did not exceed 1 log CFU/mL. Increasing the NET also increased the likelihood for the spores to remain longer in the effective distance from the UVC source, estimated as 0.02 mm for whole milk and 0.06 mm for skim milk. Combination of UHPH and UVC did not clearly increase the efficiency of a single UVC treatment, and a lower lethality was even observed in some cases. UHPH treatments increased the turbidity and absorption coefficient (254 nm) of both whole and skim milk.

Interaction of Photoprotective and Acclimation Mechanisms in Ulva rigida (Chlorophyta) in Response to Diurnal Changes in Solar Radiation in Southern Chile.

Species of the genus Ulva (Chlorophyta) are regarded as opportunistic organisms, which efficiently adjust their metabolism to the prevailing environmental conditions. In this study, changes in chlorophyll-a fluorescence-based photoinhibition of photosynthesis, electron transport rates, photosynthetic pigments, lipid peroxidation, total phenolic compounds, and antioxidant metabolism were investigated during a diurnal cycle of natural solar radiation in summer (for 12h) under two treatments: photosynthetically active radiation (PAR: 400-700nm) and PAR+ ultraviolet (UV) radiation (280-700nm). In the presence of PAR alone, Ulva rigida showed dynamic photoinhibition, and photosynthetic parameters and pigment concentrations decreased with the intensification of the radiation. On the other hand, under PAR+UV conditions a substantial decline up to 43% was detected and an incomplete fluorescence recovery, also, P-I curve values remained low in relation to the initial condition. The phenolic compounds increased their concentration only in UV radiation treatments without showing a correlation with the antioxidant activity. The enzimatic activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX) increased over 2-fold respect at initial values during the onset of light intensity. In contrast, catalase (CAT) increased its activity rapidly in response to the radiation stress to reach maxima at 10a.m. and decreasing during solar. The present study suggests that U.rigida is capable of acclimating to natural radiation stress relies on a concerted action of various physiological mechanisms that act at different times of the day and under different levels of environmental stress.

Delivery of long chain C16 and C24 ceramide in HeLa cells using oxidized graphene nanoribbons.

The bioactive sphingolipid ceramide has many important roles in cell signaling processes, particularly in signaling programmed cell death in cancer. However, ceramide levels are often impaired in multi-drug resistant and radiation resistant cancers due to the dysregulation of ceramide metabolism. Restoration of ceramide levels through external delivery therefore represents a potential therapeutic target for the treatment of resistant cancers. However, as a lipid, ceramide is extremely hydrophobic and requires a delivery system to enter cells. Here we report the development of a method to load significant amounts of the long chain C16 and C24 ceramides onto oxidized graphene nanoribbons (O-GNRs) derived from carbon nanotubes. Using O-GNRs as a delivery system for these ceramides, we were able to induce significant biological effects in HeLa cells in conjunction with C6 ceramide and ultraviolet radiation treatment. However, we found that O-GNRs themselves exert significant biological effects and can interfere with the actions of these ceramides and ultraviolet treatment. Loading of ceramides onto O-GNRs did not have a significant effect on the entry of the nanoparticles into cells. Despite the need for further improvement, these data represent an important first step in the development of O-GNRs as a delivery system for long chain ceramides.

Transcriptome sequencing of a toxic dinoflagellate, Karenia mikimotoi subjected to stress from solar ultraviolet radiation

Solar ultraviolet radiation (UVR) is a stress factor in aquatic environments and may act directly or indirectly on orgnisms in the upper layers of the water column. However, UVR effects are usually species-specific and difficult to extrapolate. Here we use the HAB-forming, toxic dinoflagellate Karenia mikimotoi (which was found to be relatively resistant in previous studies) to investigate its transcriptional responses to a one-week UVR exposure. For this, batch cultures of K. mikimotoi were grown with and without UVR, and their transcriptomes (generated via RNAseq technology) were compared. RNA-seq generated 45.31 million reads, which were further assembled to 202600 unigenes (>300bp). Among these, ca. 61% were annotated with NCBI, NR, GO, KOG, PFAM, Swiss-Prot, and KEGG database. Transcriptomic analysis revealed 722 differentially expressed unigenes (DEGs, defined as being within a |log2 fold change| ≥ 2 and padj < 0.05) responding to solar UVR, which were only 0.36% of all unigenes. 716 unigenes were down-regulated, and only 6 unigenes were up-regulated in the UVR compared to non-UVR treatment. KEGG pathway further analysis revealed DEGs were involved in the different pathway; genes involved in the ribosome, endocytosis and steroid biosynthesis pathways were highly down-regulated, but this was not the case for those involved in the energy metabolisms (including photosynthesis, oxidative phosphorylation) which may contribute to the sustainable growth observed in UVR treatment. The up-regulated expression of both zinc-finger proteins (ZFPs) and ribosomal protein L11 (RPL11) may be one of the acclimated mechanisms against UVR. In addition, this work identified down-regulated genes involved in fatty acid degradation and the hydrophobic branched chain amino acids (e.g., Valine, leucine, and isoleucine), which act as structural components of cell membranes modulating lipid homeostasis or turnover. In conclusion, the present study suggests that the toxic dinoflagellate K. mikimotoi has limited transcriptomic regulation but confirms that it appears as a tolerant species in response to solar UVR. These findings expand current knowledge of gene expression in HAB-forming species in response to natural environment factors such as solar radiation.

The effects of mutation and temperature variation on monacolin K production by monascus sp. and relative statistical parameter analysis of monacolin K production

Monacolin K is a secondary metabolite of the Monascus species that restrains cholesterol synthesis. Temperature control is an effective method of improving the rate of monacolin K synthesis. Ultraviolet (UV) irradiation and ethylmethane sulfonate (EMS) were employed to mutate the Monascus strain so that it could be studied. After mutation by UV and EMS, the best monacolin K production strain was scanned after the 2 -h UV irradiation treatment. Monascus U-2 is defined as Monascus after UV irradiation for 2 h and generates the maximum production of monacolin K production. In the primary incubation period, monacolin K production of this strain was exceptionally low. Afterwards, cell growth reached the maximum value of 1.1 g/L after incubation for seven days. During the incubation process, the maximum production of monacolin K reached 8437.6 mg/kg by Monascus U-2, and the red pigment was 11.52. In summary, this study shows that the mutated strain U-2 can produce more monacolin K than the mutated strain U-10 and U-EMS.

Reaumuria trigyna transcription factor RtWRKY23 enhances salt stress tolerance and delays flowering in plants

Reaumuria trigyna (Reaumuria Linn genus, family Tamaricaceae), an endangered dicotyledonous shrub with the features of a recretohalophyte, is endemic to the Eastern Alxa–Western Ordos area of China. Based on R. trigyna transcriptome data and expression pattern analysis of RtWRKYs, RtWRKY23, a Group II WRKY transcription factor, was isolated from R. trigyna cDNA. RtWRKY23 was mainly expressed in the stem and was induced by salt, drought, cold, ultraviolet radiation, and ABA treatments, but suppressed by heat treatment. Overexpression of RtWRKY23 in Arabidopsis increased chlorophyll content, root length, and fresh weight of the transgenic lines under salt stress. Real-time quantitative PCR (qPCR) analysis and yeast one-hybrid analysis demonstrated that RtWRKY23 protein directly or indirectly modulated the expression levels of downstream genes, including stress-related genes AtPOD, AtPOD22, AtPOD23, AtP5CS1, AtP5CS2, and AtPRODH2, and reproductive development-related genes AtMAF5, AtHAT1, and AtANT. RtWRKY23 transgenic Arabidopsis had higher proline content, peroxidase activity, and superoxide anion clearance rate, and lower H2O2 and malondialdehyde content than WT plants under salt stress conditions. Moreover, RtWRKY23 transgenic Arabidopsis exhibited later flowering and shorter pods, but little change in seed yield, compared with WT plants under salt stress. Our study demonstrated that RtWRKY23 not only enhanced salt stress tolerance through maintaining the ROS and osmotic balances in plants, but also participated in the regulation of flowering under salt stress.

Effect of decontamination treatment on the quality of dehydrated thyme, coriander, and mustard.

The objective of this work was to evaluate the effects of different decontamination treatments on the quality of dehydrated thyme, coriander, and mustard. Treatments applied were: (i) ultraviolet radiation treatment irradiation; (ii) steam, (iii) steam-ultraviolet radiation treatment; (iv) humidification-ultraviolet radiation treatment, and (v) steam-humidification-ultraviolet radiation treatment. Their effectiveness to control indigenous aerobic mesophiles and yeasts and molds population was assessed by plate count. The effect of proposed treatments on total polyphenol contents and antioxidant activity was also evaluated. Furthermore, the effect of treatments on spices performance to prevent canola oil oxidation was also analyzed. The use of steam-ultraviolet radiation treatment in aqueous medium was the most effective for decontamination, reducing the aerobic mesophiles and yeasts and molds counts between 1.0 and 2.2 log CFU/g dry spice. This treatment decreased significantly the polyphenol content and the antioxidant capacity of the three spices analyzed. However, in the case of mustard, the residual antioxidant compounds were able to control canola oil oxidation more efficiently than butylated hydroxytoluene. Results suggest that the use of steam-ultraviolet radiation treatment in aqueous medium can be useful in food preservation processes.