Providing inoculum for Didymella bryoniae studies: the effect of light spectrum and storing at low temperature

Abstract The in vitro sporulation of Didymella bryoniae is of great importance for studies that require pure inoculum and in large quantities. Thus, the objectives of this study were to identify the best condition for D. bryoniae sporulation combining different light spectra (UV-A or UV-B light, white light, and continuous dark), with distinct culture media (PDA, V8, ML, and PDAB) and, to evaluate fungus survivability stored at -20°C over time. The fungus samples were only able to sporulate when subjected to the UV-B light treatment, regardless of the culture medium. The highest appearance of spores conidium type was observed in the PDAB medium, and the lowest production occurred in the ML medium. Reproductive structures, such as perithecia and pycnidia, were observed in all culture media. However, there was considerable variation in the amount of each structure between the different culture media. The ML and V8 media showed a greater number of perithecia and the PDA and PDAB media presented a greater proportion of pycnidia compared to perithecia. The storage duration at -20°C did not affect mycelial growth or mycelial growth rate. In conclusion, the UV-B light is essential for D. bryoniae in vitro sporulation. Moreover, the culture medium composition influences the type of fungal structure produced, as well as spores size and quantity. Freezing at -20°C is an efficient technique that can be used to store D. bryoniae for at least five months without loss of viability.

Resumo A esporulação de Didymella bryoniae in vitro é de grande importância para estudos que requerem inóculo puro e em grandes quantidades. Assim, os objetivos deste estudo foram identificar a melhor condição para esporulação de D. bryoniae combinando diferentes espectros de luz (luz UV-A ou UV-B, luz branca e escuro contínuo) com distintos meios de cultura (PDA, V8, ML e PDAB) e, avaliar a sobrevivência do fungo armazenado a -20°C ao longo do tempo. As amostras de fungo só esporularam quando submetidas ao tratamento com luz UV-B, independentemente do meio de cultura. Maior aparecimento de esporos do tipo conídio foi observado no meio PDAB, e a menor produção ocorreu no meio ML. Estruturas reprodutivas, como peritécios e picnídeos, foram observadas em todos os meios de cultura. No entanto, houve uma variação considerável na quantidade de cada estrutura entre os diferentes meios de cultura. Os meios ML e V8 apresentaram maior número de peritécios e os meios PDA e PDAB apresentaram maior proporção de picnídeos em relação aos peritécios. A duração do armazenamento a -20°C não afetou o crescimento micelial ou a taxa de crescimento micelial. Em conclusão, a luz UV-B é essencial para a esporulação de D. bryoniae in vitro. Além disso, a composição do meio de cultura influencia o tipo de estrutura fúngica produzida, bem como o tamanho e a quantidade dos esporos. O congelamento a -20°C é uma técnica eficiente que pode ser usada para armazenar D. bryoniae por pelo menos cinco meses sem perda de viabilidade

Providing inoculum for Didymella bryoniae studies: the effect of light spectrum and storing at low temperature / Fornecendo inóculo para estudos de Didymella bryoniae: o efeito do espectro de luz e armazenamento em baixa temperatura

Abstract The in vitro sporulation of Didymella bryoniae is of great importance for studies that require pure inoculum and in large quantities. Thus, the objectives of this study were to identify the best condition for D. bryoniae sporulation combining different light spectra (UV-A or UV-B light, white light, and continuous dark), with distinct culture media (PDA, V8, ML, and PDAB) and, to evaluate fungus' survivability stored at -20°C over time. The fungus samples were only able to sporulate when subjected to the UV-B light treatment, regardless of the culture medium. The highest appearance of spores conidium type was observed in the PDAB medium, and the lowest production occurred in the ML medium. Reproductive structures, such as perithecia and pycnidia, were observed in all culture media. However, there was considerable variation in the amount of each structure between the different culture media. The ML and V8 media showed a greater number of perithecia and the PDA and PDAB media presented a greater proportion of pycnidia compared to perithecia. The storage duration at -20°C did not affect mycelial growth or mycelial growth rate. In conclusion, the UV-B light is essential for D. bryoniae in vitro sporulation. Moreover, the culture medium composition influences the type of fungal structure produced, as well as spores' size and quantity. Freezing at -20°C is an efficient technique that can be used to store D. bryoniae for at least five months without loss of viability.

Resumo A esporulação de Didymella bryoniae in vitro é de grande importância para estudos que requerem inóculo puro e em grandes quantidades. Assim, os objetivos deste estudo foram identificar a melhor condição para esporulação de D. bryoniae combinando diferentes espectros de luz (luz UV-A ou UV-B, luz branca e escuro contínuo) com distintos meios de cultura (PDA, V8, ML e PDAB) e, avaliar a sobrevivência do fungo armazenado a -20°C ao longo do tempo. As amostras de fungo só esporularam quando submetidas ao tratamento com luz UV-B, independentemente do meio de cultura. Maior aparecimento de esporos do tipo conídio foi observado no meio PDAB, e a menor produção ocorreu no meio ML. Estruturas reprodutivas, como peritécios e picnídeos, foram observadas em todos os meios de cultura. No entanto, houve uma variação considerável na quantidade de cada estrutura entre os diferentes meios de cultura. Os meios ML e V8 apresentaram maior número de peritécios e os meios PDA e PDAB apresentaram maior proporção de picnídeos em relação aos peritécios. A duração do armazenamento a -20°C não afetou o crescimento micelial ou a taxa de crescimento micelial. Em conclusão, a luz UV-B é essencial para a esporulação de D. bryoniae in vitro. Além disso, a composição do meio de cultura influencia o tipo de estrutura fúngica produzida, bem como o tamanho e a quantidade dos esporos. O congelamento a -20°C é uma técnica eficiente que pode ser usada para armazenar D. bryoniae por pelo menos cinco meses sem perda de viabilidade

Actin filaments altered distribution in wheat (Triticum aestivum) "Bending Root" to respond to enhanced Ultraviolet-B radiation / Distribuição alterada dos filamentos de actina no trigo (Triticum aestivum) "Raiz dobrada" para responder à radiação ultravioleta B aprimorada

Abstract Plants adjust their shoot growth to acclimate to changing environmental factors, such as to enhanced Ultraviolet-B (UV-B) radiation. However, people have ignored that plant roots can also respond to UV-B light. Here, we find the morphology curled wheat roots under UV-B radiation, that we call, "bending roots." The curly region is the transition zone of the root after observed at the cellular level. After exposed to enhanced UV-B radiation for 2 d (10.08 KJ/m2/d), cell size decreased and actin filaments gathered in wheat roots. We also find that H2O2 production increased and that content of the indole-3-acetic acid (IAA) increased remarkably. The pharmacological experiment revealed that actin filaments gathered and polymerized into bundles in the wheat root cells after irrigated H2O2 and IAA. These results indicated that actin filaments changed their distribution and formed the "bending root," which was related to H2O2 production and increase in IAA. Overall, actin filaments in wheat root cells could be a subcellular target of UV-B radiation, and its disruption determines root morphology.

Resumo As plantas ajustam o crescimento da parte aérea para se adaptarem a fatores ambientais variáveis, como o aumento da radiação ultravioleta B (UVB). No entanto, as pessoas ignoram que as raízes das plantas também podem responder à luz UVB. Neste estudo, verificamos a morfologia das raízes enroladas de trigo sob radiação UVB, o que chamamos de "raízes dobradas". A região encaracolada é a zona de transição da raiz no nível celular. Depois de exposição à radiação UVB aprimorada por 2 dias (10,08 KJ/m2/d), o tamanho das células diminuiu, e os filamentos de actina se reuniram. Também constatamos que a produção de H2O2 aumentou e que o conteúdo do ácido indol-3-acético (IAA) aumentou notavelmente. O experimento farmacológico revelou que os filamentos de actina se reuniram e polimerizaram em feixes nas células da raiz de trigo após irrigação com H2O2 e IAA. Esses resultados indicam que os filamentos de actina alteraram sua distribuição e formaram a "raiz dobrada", relacionada à produção de H2O2 e ao aumento do IAA. No geral, os filamentos de actina nas células da raiz de trigo podem ser um alvo subcelular da radiação UVB, e sua interrupção determina a morfologia da raiz.

Modulated UV-B radiation invoking cytomorphological and biochemical aspects of a medicinal plant, Bhringraj (Eclipta alba (L.) Hassk.)

Aim: The current experimental work has been designed to study the effect of UV-B exposure on the seedling growth and meiotic consequences of Eclipta alba (L.) Hassk.Methodology: The seedlings were exposed to UV-B radiation for different time durations, i.e., 40, 80, 120 min along with control sets. UV-B irradiated seedlings along with respective controls were sown in the field and young floral buds were fixed in Carnoy’s fixative for 24 hrs and preserved in 90% ethanol for meiotic study. Results: Exposure of UV-B exposure resulted in various chromosomal aberrations like stickiness, laggards, bridges, unorientation, precocious, multivalents etc. Chromosomal stickiness was profound abnormality encountered at shorter duration (40 min) to UV-B exposure. The results revealed that UV-B exposure for shorter duration is quite beneficial to plant as it induces significant cytomorphological and biochemical variations. Interpretation: Shorter exposure to UV-B radiation induced certain beneficial traits in Eclipta alba. Since, Eclipta alba is a medicinally significant plant, hence, it is essential to improve their quantitative and qualitative traits through induced mutagenesis using UV-B radiation to impel the novel characteristics of plant

Studies on hill stream fish photosensitivity with psoralene and retene photosensitizers

Aim: A study was designed to measure the solar UV- B in Uttarakhand, Garhwal region and to observe the effect of retene and psoralene photosensitizers on hill stream fishes, Tor tor and Garra gotyla in the presence of natural solar ultraviolet and equal intensity of artificial UV-B radiation.Methodology: Solar UV-B was measured with the help of Kipps and Zonen radiometer having UV-B sensors. Experimental sites selected were Dehradun and Tehri located in Garhwal region of Uttarakhand. The artificial radiation was provided with Philips UV-B Lamps. Mortality, biochemical and enzymological parameters, which included glutathione, glucose-6-phosphatase, catalase and lipid peroxidation were analyzed. Results: The data of monitoring of UV-B showed that the maximum UV-B intensity was observed during the month of May to August and the minimum was in the month of December to February. Mortality rate of fish exposed to solar radiation, artificial UV-B, psoralene and retene indicated highest with 26% in Tor tor, exposed with psoralene+ artificial UV-B. Reduced glutathione, glucose- 6- phosphatase and catalase level decreased in all the groups compared to control. The maximum reduction in GSH level was observed after treatment of artificial UV-B + psoralene in Tor tor, while maximum reduction in catalase and glucose-6- phosphatase was observed after retene and artificial UV-B. Interpretation: Tor tor and Garra gotyla are important hill stream fishes. Retene and psoralene are natural photosensitizers present in the aquatic ecosystem and become phototoxic by generating oxidative radicals. Artificial UV-B was more toxic than natural solar radiation and Tor tor was found more sensitive than Garra gotyla. Enhanced UV-B with retene and psoralene photosensitizers affect hill stream fishes and aquatic biodiversity.

Actin filaments mediated root growth inhibition by changing their distribution under UV-B and hydrogen peroxide exposure in Arabidopsis

BACKGROUND: UV-B signaling in plants is mediated by UVR8, which interacts with transcriptional factors to induce root morphogenesis. However, research on the downstream molecules of UVR8 signaling in roots is still scarce. As a wide range of functional cytoskeletons, how actin filaments respond to UV-B-induced root morphogenesis has not been reported. The aim of this study was to investigate the effect of actin filaments on root morphogenesis under UV-B and hydrogen peroxide exposure in Arabidopsis. RESULTS: A Lifeact-Venus fusion protein was used to stain actin filaments in Arabidopsis. The results showed that UV-B inhibited hypocotyl and root elongation and caused an increase in H2O2 content only in the root but not in the hypocotyl. Additionally, the actin filaments in hypocotyls diffused under UV-B exposure but were gathered in a bundle under the control conditions in either Lifeact-Venus or uvr8 plants. Exogenous H2O2 inhibited root elongation in a dose-dependent manner. The actin filaments changed their distribution from filamentous to punctate in the root tips and mature regions at a lower concentration of H2O2 but aggregated into thick bundles with an abnormal orientation at H2O2 concentrations up to 2 mM. In the root elongation zone, the actin filament arrangement changed from lateral to longitudinal after exposure to H2O2. Actin filaments in the root tip and elongation zone were depolymerized into puncta under UV-B exposure, which showed the same tendency as the low-concentration treatments. The actin filaments were hardly filamentous in the maturation zone. The dynamics of actin filaments in the uvr8 group under UV-B exposure were close to those of the control group. CONCLUSIONS: The results indicate that UV-B inhibited Arabidopsis hypocotyl elongation by reorganizing actin filaments from bundles to a loose arrangement, which was not related to H2O2. UV-B disrupted the dynamics of actin filaments by changing the H2O2 level in Arabidopsis roots. All these results provide an experimental basis for investigating the interaction of UV-B signaling with the cytoskeleton.

Changes in Morpho-physiological and Yield Parameters of Rice (Oryza sativa L.) in Response to Ultraviolet-B (UV-B) Radiation

A rice variety Jyothi (PTB 39) is a red kernelled with bold grain, popular in the region of Kerala, India used in the study. Plants were grown in pots under three different conditions, natural solar UV-B conditions, UV-B excluded condition using UV-B filters and supplemental UV-B using UV-B lamps along with ambient solar radiation. During the study period, UV-B radiation was in the range of 1.30 to 3.58 Wm2 which affected the productivity of the crop under open solar condition. A decrease in morphological traits like plant height, number of tillers, flag leaf angle and increase in leaf thickness were observed. Physiological parameters, leaf gas exchange parameters and biochemical constituents such as chlorophyll content also recorded less value under high UV-B condition along with the high content of protective compounds such as flavonoid content, catalase and PAL activity. The phenophases of the crop were also delayed by 4-5 days under UV-B radiation exposed conditions. All these negative impacts of UV-B radiation on crop leads to restricted filling of grain, lesser harvest index and grain development leading to a decrease in yield and yield attributing characters.

Induced genetic variations in Cuminum cyminum through supplemental UV-B radiation

Aim: The present study was conducted to investigate the genotoxic effect of UV-B radiation on morphological, biochemical and cytological parameters of Cuminum cyminum. Methodology: The germinated roots of cumin were exposed to UV-B radiation at different intervals viz., 20 min 40 min and 60 min, respectively, and some treated seeds were sown on pots for morphological and biochemical observation. Results: Chromosomal studies divulged that UV-B radiation has substantial impact on Active Mitotic Index (AMI %). On increasing UV-B radiation dose, the chromosomal aberration rate elevated, thus AMI % moderately decreased and Total Abnormality percentage (TAB %) gradually increased. Different types of chromosomal abnormalities were ascertained, among which scattering was more prominent. The morphological observation showed that survival percentage and plant height decreased at elevated dose of UV-B. Biochemical results indicated that chlorophyll a, chlorophyll b and carotenoid contents decreased as compared to control, but proline content showed significant increment at higher doses of UV-B.Interpretation: The observation elucidates that UV-B causes chromosomal aberrations during cell division and acts as a potent genotoxic agents for roots. Thus, it can be concluded from the above experiment that UV-B rays promote plant growth at low doses but at the higher doses, it subsequently hinders plant growth by damaging important constituents of plant cell.

Photoprotection enhanced by red cell wall pigments in three East Antarctic mosses

BACKGROUND: Antarctic bryophytes (mosses and liverworts) are resilient to physiologically extreme environmental conditions including elevated levels of ultraviolet (UV) radiation due to depletion of stratospheric ozone. Many Antarctic bryophytes synthesise UV-B-absorbing compounds (UVAC) that are localised in their cells and cell walls, a location that is rarely investigated for UVAC in plants. This study compares the concentrations and localisation of intracellular and cell wall UVAC in Antarctic Ceratodon purpureus, Bryum pseudotriquetrum and Schistidium antarctici from the Windmill Islands, East Antarctica. RESULTS: Multiple stresses, including desiccation and naturally high UV and visible light, seemed to enhance the incorporation of total UVAC including red pigments in the cell walls of all three Antarctic species analysed. The red growth form of C. purpureus had significantly higher levels of cell wall bound and lower intracellular UVAC concentrations than its nearby green form. Microscopic and spectroscopic analyses showed that the red colouration in this species was associated with the cell wall and that these red cell walls contained less pectin and phenolic esters than the green form. All three moss species showed a natural increase in cell wall UVAC content during the growing season and a decline in these compounds in new tissue grown under less stressful conditions in the laboratory. CONCLUSIONS: UVAC and red pigments are tightly bound to the cell wall and likely have a long-term protective role in Antarctic bryophytes. Although the identity of these red pigments remains unknown, our study demonstrates the importance of investigating cell wall UVAC in plants and contributes to our current understanding of UV-protective strategies employed by particular Antarctic bryophytes. Studies such as these provide clues to how these plants survive in such extreme habitats and are helpful in predicting future survival of the species studied.

A case of disseminated granuloma annulare successfully treated with acitretin and narrowband UV-B phototherapy

Introduction@#Granuloma annulare(GA) is a benign, inflammatory skin condition characterized by asymptomatic, flesh colored or erythematous papules. The disseminated variant of granuloma annulare is uncommon, usually affecting women older than 40 years.@*Case Summary@#We report a case of a 52-year-old female, who presented with a 4-year history of skin colored to erythematous papules and annular plaques covering the entire skin surface. Correlation of the clinical presentation, histopathology and dermoscopy findings established the diagnosis of disseminated granuloma annulare. The patient was treated with 25 sessions of narrowband ultraviolet-B (NB-UVB) phototherapy and acitretin 20mg/day for 5 months.@*Conclusion@#Both histopathology and dermoscopy were noted to be valuable tools in the diagnosis of disseminated GA, as well as in monitoring response to the combined therapy.

Actin filaments altered distribution in wheat (Triticum aestivum) Bending Root to respond to enhanced Ultraviolet-B radiation

Abstract Plants adjust their shoot growth to acclimate to changing environmental factors, such as to enhanced Ultraviolet-B (UV-B) radiation. However, people have ignored that plant roots can also respond to UV-B light. Here, we find the morphology curled wheat roots under UV-B radiation, that we call, bending roots. The curly region is the transition zone of the root after observed at the cellular level. After exposed to enhanced UV-B radiation for 2 d (10.08 KJ/m2/d), cell size decreased and actin filaments gathered in wheat roots. We also find that H2O2 production increased and that content of the indole-3-acetic acid (IAA) increased remarkably. The pharmacological experiment revealed that actin filaments gathered and polymerized into bundles in the wheat root cells after irrigated H2O2 and IAA. These results indicated that actin filaments changed their distribution and formed the bending root, which was related to H2O2 production and increase in IAA. Overall, actin filaments in wheat root cells could be a subcellular target of UV-B radiation, and its disruption determines root morphology.

Resumo As plantas ajustam o crescimento da parte aérea para se adaptarem a fatores ambientais variáveis, como o aumento da radiação ultravioleta B (UVB). No entanto, as pessoas ignoram que as raízes das plantas também podem responder à luz UVB. Neste estudo, verificamos a morfologia das raízes enroladas de trigo sob radiação UVB, o que chamamos de raízes dobradas. A região encaracolada é a zona de transição da raiz no nível celular. Depois de exposição à radiação UVB aprimorada por 2 dias (10,08 KJ/m2/d), o tamanho das células diminuiu, e os filamentos de actina se reuniram. Também constatamos que a produção de H2O2 aumentou e que o conteúdo do ácido indol-3-acético (IAA) aumentou notavelmente. O experimento farmacológico revelou que os filamentos de actina se reuniram e polimerizaram em feixes nas células da raiz de trigo após irrigação com H2O2 e IAA. Esses resultados indicam que os filamentos de actina alteraram sua distribuição e formaram a raiz dobrada, relacionada à produção de H2O2 e ao aumento do IAA. No geral, os filamentos de actina nas células da raiz de trigo podem ser um alvo subcelular da radiação UVB, e sua interrupção determina a morfologia da raiz.

Ellagic acid plays a protective role against UV-B-induced oxidative stress by up-regulating antioxidant components in human dermal fibroblasts

Ellagic acid (EA), an antioxidant polyphenolic constituent of plant origin, has been reported to possess diverse pharmacological properties, including anti-inflammatory, anti-tumor and immunomodulatory activities. This work aimed to clarify the skin anti-photoaging properties of EA in human dermal fibroblasts. The skin anti-photoaging activity was evaluated by analyzing the reactive oxygen species (ROS), matrix metalloproteinase-2 (MMP-2), total glutathione (GSH) and superoxide dismutase (SOD) activity levels as well as cell viability in dermal fibroblasts under UV-B irradiation. When fibroblasts were exposed to EA prior to UV-B irradiation, EA suppressed UV-B-induced ROS and proMMP-2 elevation. However, EA restored total GSH and SOD activity levels diminished in fibroblasts under UV-B irradiation. EA had an up-regulating activity on the UV-B-reduced Nrf2 levels in fibroblasts. EA, at the concentrations used, was unable to interfere with cell viabilities in both non-irradiated and irradiated fibroblasts. In human dermal fibroblasts, EA plays a defensive role against UV-B-induced oxidative stress possibly through an Nrf2-dependent pathway, indicating that this compound has potential skin antiphotoaging properties.

Changes of secondary metabolites and differential proteomics in mulberry leaves under UV-B induction / 中国药学杂志

OBJECTIVE: To investigate the influence of ultraviolet B (UV-B) induction on the content of two kinds of secondary metabolites in mulberry leaves and differential proteomics under UV-B induction. METHODS: The HPLC chromatograms of secondary metabolites in leaves before and after UV-B induction were established and quantitative analysis of two kinds of secondary metabolites was performed. The subcellular structure of mulberry leaves under UV-B induction was observed using transmission electron microscopy. Proteomic analysis of mulberry leaves was performed using two-dimensonal electrophoresis (2-DE). RESULTS: The subcellular structure of mulberry leaves was destroyed under UV-B induction. The contents of moracin N and chalcomoracin in mulberry leaves were increased with the dark incubation time and they maximized at 36 and 40 h, respectively. The result of proteomics showed that the abundance of chalcone synthase (CHS) which is the key enzyme of flavonoid biosynthesis pathway was increased significantly. CONCLUSION: The secondary metabolism especially for flavonoids biosynthesis in mulberry leaves is changed under UV-B induction and dark incubation, which result in the increased moracin N and chalcomarcin.

Physiological responses of Catla catla larvae fed with Achyranthes aspera seed enriched diet and exposed to UV-B radiation.

The antioxidant and growth stimulating properties of seeds of Achyranthes aspera were evaluated on UV-B irradiated Catla catla (catla) larvae. Catla larvae (initial weight: 1.2 ± 0.01 mg) were fed with four different diets — D1, D2 and D3 containing 0.1, 0.25 and 0.5% seeds of A. aspera and D4, control diet for 35 days. The larvae were then exposed to UV-B radiation (80 µW/cm2) on every alternate day for 20 days. Survival, growth, tissue glutamic oxaloacetic transminase (GOT), tissue glutamate pyruvate transminase (GPT), thiobarbituric acid reactive substances (TBARS) and nitric oxide synthase (NOS) were studied in larvae on day-21 of irradiation. Significantly (P < 0.05) higher survival and average weight were found in D3 diet fed fish compared to the other groups. Survival rate was 8-16% higher in seed enriched diet fed groups, compared to the control one. Higher levels of GOT and GPT found in control diet fed larvae showed the degree of tissue damage due to UV-B exposure. Significantly (P < 0.05) lower level of GPT in D3 indicated the UV-B protective effect of the seed of A. Aspera (earlier, the presence of ecdysterone, essential fatty acids and amino acids, polyphenolic compounds, steroids, etc. has been reported from seed). TBARS which indicated the level of tissue lipid peroxidation were significantly (P < 0.05) higher in control group, compared to the other feeding schemes. NOS level was significantly (P < 0.05) higher in D2 and D3, compared to the D1 and control groups. In conclusion, supplementation of A. aspera seed (0.5%) improved the physiological condition (in terms of reduce lipid oxidation and better immune system) and gave bioprotection to catla larvae challenged with UV-B stress.

Enhanced biosynthesis of quercetin occurs as A photoprotective measure in Lycopersicon esculentum mill. under Acute UV-B exposure

Lycopersicon esculentum respond to UV-B by enhanced synthesis of flavonoid quercetin, a strong antioxidant that helps the plants to well acclimatize to UV-B stress. Three weeks old plants of L. esculentum were subjected to acute UV-B irradiation for 20, 40 and 60 minutes daily until 28 days and analyzed for the morphological and biochemical changes. UV-B exposure for 40 and 60 minutes considerably affected the growth and biomass of L. esculentum. The leaves were deformed, developed chlorosis and abscised early as compared to the unexposed plants. Biomass declined by 35% and total chlorophyll decreased by 24.7% due to disintegration of chloroplasts. Enhancement was seen in the content of carotenoids, anthocyanins and total flavonoids by 15, 33.3 and 22.8%, respectively, which was attributed to the photoprotective role of these compounds as potential quenchers of excess excitation energy. Quercetin content decreased on UV-B exposure to 20 and 40 min, and thereafter increased significantly by 5.19% on 60 min of exposure. This pattern probably indicated that the over-expression of genes involved in its biosynthesis such as phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), flavanone 3-hydroxylase (F3H) and dihydroflavonol 4-reductase (DFR) occurred only after certain threshold exposure (60 min), which could be the strategy for developing tolerance against UV-B stress in L. esculentum.

Anti-psoriatic activity of flavonoids from Cassia tora leaves using the rat ultraviolet B ray photodermatitis model

The plant Cassia tora L., Fabaceae, traditionally, is claimed to be useful in the treatment of psoriasis and other skin diseases. In order to evaluate this information, antipsoriatic activity of three flavonoids, namely luteolin-7-O-β-glucopyranoside (1), quercetin-3-O-β-D-glucuronide (2) and formononetin-7-O-β-D-glucoside (3), isolated from the ethanol extract of C. tora leaves were investigated using UV-B induced photodermatitis model. Further, the flavonoids present in the ethanol extract were identified using HPLC by comparing their retention time with known standard luteolin, quercetin and formononetin. In the UV induced photodermatitis model, histopathological analysis of the section revealed the absence of Munro's microabscess, elongation of rete ridges, and capillary loop dilation in ethanol extract (400 mg/kg), isolated compound 2, 3 and standard group. The ethanolic extract (400 mg/kg) and isolated compounds 1, 2 and 3 exhibited a significant (p < 0.01) percentage reduction of relative epidermal thickness when compared with a positive control. In the HPLC analysis, three flavonoids were identified by comparison of the retention times of standard marker, namely luteolin, quercetin and formononetin. We concluded, using animal model, that the flavonoids from Cassia tora leaves have significant antipsoriatic activity. .

Production of phenolic metabolites by Deschampsia antarctica shoots using UV-B treatments during cultivation in a photobioreactor

Deschampsia antarctica (DA), the only species in the Gramineae family endemic to the Antarctic territory, is characterized by a combination of high levels of free endogenous phenylpropanoid compounds under normal in situ and in vitro growth conditions. In this article, we describe the design and use of a specific temporary immersion photobioreactor to produce both increased DA biomass and secondary metabolite accumulation by UV-B elicitation during cultivation. Three min-long immersions in an induction medium applied every 4 hrs at 14ºC +/- 1 and 20/4 hrs light/darkness photoperiod increased DA biomass production over previous in vitro reports. Biomass duplication was obtained at day 10.7 of culturing, and maximum total phenolics and antioxidant activity were observed after 14 day of culturing. The addition of UV-B radiation pulses for 0.5 hrs at 6 hrs intervals increased total phenolics and antioxidant activity more than 3- and 1.5- fold, respectively, compared to controls with no UV-B. Significant accumulation of scopoletin, chlorogenic acid, gallic acid and rutin was found in these plantlets. This is the first bioreactor designed to optimize biomass and phenylpropanoid production in DA.

Study on influence of UV-B induction on accumulation of secondary metabolites in postharvest leaves of Mahonia bealei (Fort.) Carr / 中国药学杂志

OBJECTIVE: To investigate the influence of UV-B induction on the content of secondary metabolites, three kinds of alkaloid especially, in post-harvest leaves of Mahonia bealei (Fort.) Carr.. METHODS: The HPLC chromatograms of secondary metabolites in leaves before and after UV-B induction were established, and the content changes of secondary metabolites were obtained by means of comparison and analysis. RESULTS: In comparison with the control group, the contents of the secondary metabolites after UV-B induction changed dramatically. The contents of jatrorrhizine and palmatine increased obviously and reached a plateau after UVB induction for six hours. The amplification of jatrorrhizine was 410.84% and that of palmatine reached 118.76%, but the content of berberine decreased obviously after induction. CONCLUSION: UV-B induction has remarkable effects on accumulation of secondary metabolites in postharvest leaves of Mahonia bealei (Fort.) Carr.

Differential gene expression in pepper (Capsicum annuum) exposed to UV-B.

In the present paper, complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) was used to examine and identify differentially expressed genes in Capsicum annuum exposed to UV-B irradiation. Around 4000 transcript derived fragments (TDFs) were visualized and in total 183 TDFs were isolated, sequenced and analyzed by Blast 2 go. Among these TDFs, 84 of them showed homology to known genes. There were 43 TDFs showing up-regulated expression, 24 TDFs showing down-regulated expression and 27 TDFs showing both up-regulated and down-regulated expression, respectively. Some of these TDFs were found to be in response/related to UV-B stress, including carbonic anhydrase, calcium-dependent protein, thionin-like protein, bzip protein and so on. In particular, chlorophyll a/b binding protein (Capcab) responding to UV-B stress was cloned. It was concluded that Capcab could play a protective role in plant anti-UV-B and maintaining photosynthetic rate under UV-B stress.

Supplemental UV-B radiation induced changes in growth, pigments and antioxidant pool of bean (Dolichos lablab) under field conditions.

Present study is conducted to evaluate the response of bean (Dolichos lablab cv . pusa early prolific) plants to supplemental UV-B (sUV-B: 280-315 nm: 7.2 kJ m-2 d-1) radiation. UV-B caused alteration in biomass translocation pattern with more retention of biomass in below ground parts leading to an increment in root shoot ratio. Specific leaf area (SLA) which is the measure of leaf thinness, increased in plants under sUV-B exposure by 95.7 and 82.3% after 15 and 30 days after germination. Photosynthetic machinery of bean plants was the potential target of UV-B as photosynthetic rate was decreased by 88.6 % at 30 days after germination. sUV-B lead to the formation of reactive oxygen species thus generating oxidative stress. Stimulation of antioxidant defense system (enzymatic and non-enzymatic) was observed due to sUV-B radiation. Phenolic content decreased (34.7 and 18.6%) but protein showed varied response, increased initially (34%) thereafter declined (10.2%) under sUV-B radiation.