bluuebunny/crossref_metadata_2025 huggingface dataset:
Protective Effects of Cyanidin‐3‐O‐β‐glucopyranoside Against UVA‐induced Oxidative Stress in Human Keratinocytes¶
Authors: Tarozzi Andrea , Marchesl Alessandra , Hrelia Silvana , Angeloni Cristina , Andrisano Vincenza , Fiori Jessica , Cantelli‐Forti Giorglo , Hrella Patrizia
Published: July 2010

Ultraviolet‐A (UVA) radiation causes significant oxidative stress because it leads to the generation of reactive oxygen species (ROS), leading to extensive cellular damage and eventual cell death either by apoptosis or necrosis. We evaluated the protective effects of cyanidin‐3‐O‐β‐glucopyranoside (C‐3‐G) against UVA‐induced apoptosis and DNA fragmentation in a human keratinocyte cell line (HaCaT). Treatment of HaCaT cells with C‐3‐G before UVA irradiation inhibited the formation of apoptotic cells (61%) and DNA fragmentation (54%). We also investigated antioxidant properties of C‐3‐G in HaCaT cells against ROS formation at apoptotic doses of UVA; C‐3‐G inhibited hydrogen peroxide (H2O2) release (an indicator of cellular ROS formation) after UVA irradiation. Further confirmation of the potential of C‐3‐G to counteract UVA‐induced ROS formation comes from our demonstration of its ability to enhance the resistance of HaCaT cells to the apoptotic effects of both H2O2 and the superoxide anion (O2•−), two ROS involved in UVA‐oxidative stress. Furthermore, in terms of Trolox Equivalent Antioxidant Activity, C‐3‐G treatment led to a greater increase in antioxidant activity in the membrane‐enriched fraction than in the cytosol (55%vs 19%). The protective effects against UVA‐induced ROS formation can be attributed to the higher membrane levels of C‐3‐G incorporation. These encouraging in vitro results support further research into C‐3‐G (and other anthocyanins) as novel agents for skin photoprotection.
Photooxidative Treatment of Sulfurous Water for Its Potabilization¶
Authors: Hernández Fernando , Geissler Gunther
Published: July 2010

The feasibility of potabilization of sulfurous water was investigated by photochemical oxidation processes using a batch photoreactor and a continuous‐flow photoreactor, equipped with UV lamps of 1000 W and 1500 W, respectively. Additionally, two advanced processes of oxidation were applied i.e. with a use of a UV light/H2O2/air and UV light/H2O2/O3/air. These two processes were compared for their efficiency to the direct oxidation process where ozone is used in the absence of UV light. Results obtained for both advanced processes showed better oxidation than takes place by ozone in the absence of UV light. After the photooxidation processes, different processes for the absorption or precipitation of sulfates were investigated to comply with the World Health Organization (WHO) norm that demands a limit of ≤250 mgL−1 of SO42− in drinking water. Additionally, reverse osmosis was simulated using Osmonics Inc. software to predict the feasibility of lowering the salt concentration below WHO limits.
Synthesis, Photophysical, Photochemical and Biological Properties of Caged GABA, 4‐[[(2H‐1‐Benzopyran‐2‐one‐7‐amino‐4‐methoxy) carbonyl] amino] Butanoic Acid¶
Authors: Cürten Beate , Kullmann Paul H. M. , Bier Mark E. , Kandler Karl , Schmidt Brigitte F.
Published: July 2010

The photorelease of a caged neurotransmitter can be used to investigate the function of neuronal circuits in tissues. We have designed and synthesized a stable, caged γ‐aminobutyric acid (GABA) derivative, 4‐[[(2H‐1‐benzopyran‐2‐one‐7‐amino‐4‐methoxy)carbonyl]amino] butanoic acid (BC204), that releases the neurotransmitter in physiological medium when irradiated with UV light at 300–400 nm in PBS at pH 7.4. The release of GABA occurs with the formation of the major photoproduct, 7‐amino‐4‐(hydroxymethyl)‐2H‐1‐benzopyran‐2‐one, via a solvolytic photodegradation mechanism of the coumarin moiety and was confirmed by electrospray mass spectrometry/mass spectrometry (ESI MS/MS). BC204 is chemically stable and shows no intrinsic activity after many hours under physiological dark conditions. These properties suggest that BC204 is an excellent form of caged GABA that is well suited for long‐term biological studies.
Adaptation of the Human Skin by Chronic Solar‐simulating UV Irradiation Prevents Ultraviolet‐B Irradiation‐induced Rise in Serum C‐Reactive Protein Levels¶
Authors: Laihia Jarmo K. , Koskinen Janne O. , Waris Matti E. , Jansén Christer T.
Published: July 2010

Exposure of the skin to UV radiation induces local inflammation. We hypothesized that inflammation induced by erythemal UV‐B irradiation could elevate levels of serum C‐reactive protein (CRP) and that suberythemal repeating doses of solar‐simulating UV radiation (SSR) would produce photoadaptation to such inflammation. Separation‐free high‐sensitivity assays of CRP show an increase by 42% (P= 0.046) in CRP concentrations in healthy human subjects 24 h after a 3 minimal erythemal dose (MED) dose of UV‐B delivered onto a 100 cm2 skin area. Preceding daily suberythemal doses of whole‐body SSR for 10 or 30 consecutive days completely prevented the CRP increase. UV‐B‐induced skin erythema was partially attenuated by 30 preceding days of SSR only (P= 0.00066). After 10 daily SSR doses, the mean baseline CRP concentrations (0.24 ± 0.21 mg/L) declined by 35% (P= 0.018). Using high‐sensitivity analysis of serum CRP as the endpoint marker for cutaneous inflammation, we show that acute exposure of even a relatively small skin area to erythemal UV‐B induces skin inflammation detectable also at the systemic level and that photoadaptation by preceding repeating suberythemal doses of SSR reduces signs of inflammation. Our data complement the view given by previous studies in that local photoadaptation also has systemic manifestations.
Determination of Stereochemistry of Bacteriochlorophyll gF and 81‐Hydroxy‐chlorophyll aF from Heliobacterium modesticaldum¶
Authors: Mizoguchi Tadashi , Oh‐oka Hirozo , Tamiaki Hitoshi
Published: July 2010

The reaction center complex of heliobacteria contains three kinds of chlorophyll pigments, bacteriochlorophyll gF (BChl gF), its 132‐epimer BChl g′F and 81‐hydroxy‐chlorophyll aF (81‐OH‐Chl aF). Because the full stereochemistry of these naturally occurring chlorophyllous pigments has remained unknown, we determined the stereochemistry of both BChl gF and 81‐OH‐Chl aF extracted from Heliobacterium modesticaldum. The configurations of the specific functional groups at ring‐B as well as those at ring‐D and ‐E were investigated by use of nuclear Overhauser effect correlations in their 1H‐NMR spectra and circular dichroism spectra, as well as by modified Mosher's method in their chemical modification: (1) E‐configuration was confirmed for the 8‐ethylidene group at ring‐B in BChl gF, (2) R‐configuration was identified for the 1‐hydroxyethyl group at ring‐B in 81‐OH‐Chl aF and (3) 132‐(R)‐, 17‐(S)‐ and 18‐(S)‐configurations at ring‐D and ‐E in both BChl gF and 81‐OH‐Chl aF were confirmed. These stereo‐chemistries enabled us to discuss their biosynthesis and to propose possible routes for preparation of ethylidene and 1‐hydroxyethyl groups at the 8‐position.
Photophysical Properties of Tyrosine and Its Simple Derivatives in Organic Solvents Studied by Time‐resolved Fluorescence Spectroscopy and Global Analysis¶
Authors: Guzow Katarzyna , Rzeska Alicja , Mrozek Justyna , Karolczak Jerzy , Majewski Radoslaw , Szabelski Mariusz , Ossowski Tadeusz , Wiczk Wieslaw
Published: July 2010

Photophysical properties of tyrosine and its derivatives with free and blocked functional groups were studied by steady state and time‐resolved fluorescence spectroscopy and global analysis in organic solvents, such as methanol, 2‐propanol, tetrahydrofuran (THF), and dimethylsulfoxide (DMSO). The mono‐exponential fluorescence intensity decays were observed for all tyrosine derivatives in THF and DMSO solutions, whereas in alcohols some derivatives have bi‐exponential decays. The rotamer population calculated from 1H nuclear magnetic resonance spectroscopy in DMSO does not correspond to the pre‐exponential factors obtained from fluorescence spectroscopy. Moreover in the case of DMSO, the strong interaction of this solvent with the hydroxyl group of the fluorophore's phenol ring causes substantial changes in the fluorescence and nonradiative rate constants of tyrosine derivatives compared with those of tyrosine with a blocked hydroxyl group, Tyr(Me). The steady state and time‐resolved fluorescence measurements in pure organic solvents and water‐organic solvent mixtures indicate that the fluorescence quenching of the phenol chromophore of tyrosine by an acetyl or amide group or both depends on the polarity of the solvent used as well as the ability of the solvent to form hydrogen bonds with functional groups of tyrosine.
Photophysical Properties of Crowned Porphyrins¶
Authors: Pelegrino Alessandra C. , Carolina M. M. , Gotardo A. F. , Simioni Andreza R. , Assis Marilda D. , Tedesco Antonio C.
Published: July 2010

In this study, we evaluated the photophysical properties of 5, 10, 15, 20‐tetrakis[4‐(1, 4, 7, 10, 13‐pentaoxacyclopentadecane‐2‐aminomethyl) 2, 3, 5, 6‐(tetrafluoro)‐phenyl]‐porphyrin (H2C4P) and Zn(II)5, 10, 15, 20‐tetrakis [4‐(1, 4, 7, 10, 13‐pentaox‐acyclopenta‐decane‐2‐aminomethyl) 2, 3, 5, 6‐(tetrafluoro)‐phenyl]‐porphyrinate (ZnC4P). We observed that these porphyrins have unique properties when compared with classical porphyrins. The porphyrins H2C4P and ZnC4P showed efficient transfer energy S1 to T1 by intersystem crossing with high and reasonable yields of triplet excited state and singlet oxygen production. These amphiphilic structures of these porphyrins could improve its localization in the tumor cells due to the presence of the crown ether in its framework. We also believed that the crown ether could modulate the change in ion homeostase (Ca+2, K+, Na+) as already described by some new phthalocyanine dye. This fact makes us believe that it could be reasonably used as a photosensitizer for PDT purposes.
Protection by Food‐derived Antioxidants from UV‐A1‐Induced Photodamage, Measured Using Living Skin Equivalents¶
Authors: Dekker Pim , Parish William E. , Green Martin R.
Published: July 2010

In a study of biomarkers of ultraviolet‐A1 radiation (UV‐A1)‐induced skin damage, living skin equivalent cultures (LSE) were treated with the antioxidants hesperetin and quercetin‐3‐glucoside and irradiated with 25 or 50 J/cm2 UV‐A1. Changes in the following biomarkers were measured; Interleukin 1‐alpha (IL‐1α), Heme Oxygenase‐1 (HO‐1), TdT‐mediated dUTP nick end labeling (TUNEL) and 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG). IL‐1α and HO‐1 were analyzed by realtime PCR, Western blot, enzyme‐linked immunosorbent assay (ELISA) and immunohistochemistry. TUNEL and 8‐OHdG were determined by (immuno)histochemical techniques. Sections were stained with hematoxylin and eosin (H&E). UV‐A1 induced keratinocyte and fibroblast vacuolation and nuclear pyknosis, intense TUNEL staining of fibroblasts and increased staining of cells and nuclei for 8‐OHdG. Lesser or marginal increases in intensity followed staining for HO‐1 and IL‐1α. The IL‐1α increase was confirmed by ELISA assays of the medium supernatants. Hesperetin and quercetin‐3‐glucoside reduced changes in H&E, 8‐OHdG, TUNEL and IL‐1α. Quercetin‐3‐glucoside reduced the amount of IL‐1α in LSE media. These observations support the use of the selected biomarkers to monitor UV‐A1 damage and provide evidence that dietary ingredients could reduce ultraviolet‐A radiation‐induced damage.
A New Firefly Luciferase with Bimodal Spectrum: Identification of Structural Determinants of Spectral pH‐Sensitivity in Firefly Luciferases¶
Authors: Viviani Vadim R. , Oehlmeyer T. L. , Arnoldi F. G. C. , Brochetto‐Braga M. R.
Published: July 2010

Fireflies emit flashes in the green‐yellow region of the spectrum for the purpose of sexual attraction. The bioluminescence color is determined by the luciferases. It is well known that the in vitro bioluminescence color of firefly luciferases can be shifted toward the red by lower pH and higher temperature; for this reason they are classified as pH‐sensitive luciferases. However, the mechanism and structural origin of pH sensitivity in fireflies remains unknown. Here we report the cloning of a new luciferase from the Brazilian twilight active firefly Macrolampis sp2, which displays an unusual bimodal spectrum. The recombinant luciferase displays a sensitive spectrum with the peak at 569 nm and a shoulder in the red region. Comparison of the bioluminescence spectra of Macrolampis, Photinus and Cratomorphus firefly luciferases shows that the distinct colors are determined by the ratio between green and red emitters under luciferase influence. Comparison of Macrolampis luciferase with the highly similar North American Photinus pyralis luciferase (91%) showed few substitutions potentially involved with the higher spectral sensitivity in Macrolampis luciferase. Sitedirected mutagenesis showed that the natural substitution E354N determines the appearance of the shoulder in the red region of Macrolampis luciferase bioluminescence spectrum, helping to identify important interactions and residues involved in the pH‐sensing mechanism in firefly luciferases.
Reactions of Excited States of Phenoxazin‐3‐one Dyes with Amino Acids¶
Authors: Villegas M. L. , Bertolotti S. G. , Previtali C. M. , Encinas M. V.
Published: July 2010

The interaction with amino acids of the excited states of the N‐oxide resazurin and its deoxygenation product resorufin, has been studied in aqueous solution at pH 7.5. Steady‐state and time‐resolved studies show that the fluorescence is quenched by amino acids. Complexation of the dyes in the ground state with aromatic amino acids was also observed. The singlet quenching is attributed to electron transfer from the aminoacids to the excited dye based on the dependence of the bimolecular rate constants with the ionization potential of quenchers. Flash photolysis experiments allowed determination of the quenching rate constants for the triplet deactivation of dyes by several amino acids, as well as the characterization of the transients formed in the process. These data show that the triplet is also deactivated by an electron transfer process. However, the deactivation of the N‐oxide dye by tryptophan can be described by a hydrogen atom transfer. The protolytic dissociation constants of the dye radical ions are reported. The irradiation of rezasurin in the presence of amino acids leads to deoxygenation of the dye to give resorufin. This process involves the triplet excited state of resazurin and is efficient only in the presence of amino acids containing the ‐SH group.
Light Quality Influences Indigo Precursors Production and Seed Germination in Isatis tinctoria L. and Isatis indigotica Fort.¶
Authors: Tozzi Sabrina , Lercari Bartolomeo , Angelini Luciana G.
Published: July 2010

Isatis tinctoria L. and Isatis indigotica Fort. are biennial herbaceous plants belonging to the family of Cruciferae that are used as a source of natural indigo and show several morphological and genetic differences. Production of indigo (indigotin) precursors, indican (indoxyl β‐D glucoside) and isatan B (indoxyl ketogluconate), together with seed germination ability were compared in Isatis tinctoria and Isatis indigotica grown under six different light conditions (darkness, white, red, far red, blue, yellow light) at 25°C. Light quality influenced both germination and production of indigo precursors in the two Isatis species. Different responsiveness to far red and blue light was observed. Indeed, a detrimental effect on germination by blue and far red light was found in I. tinctoria only. Different amounts of isatan B were produced under red and far red light in the two Isatis species. In I. tinctoria, the level of main indigo precursor isatan B was maximal under red light and minimal under far red light. Whereas in I. indigotica far red light promoted a large accumulation of isatan B. The photon fluence rate dependency for white and yellow light responses showed that the accumulation of indigo precursors was differently influenced in the two Isatis species. In particular, both white and yellow light enhanced above 40 μmol m−2s−1 the production of isatan B in I. indigotica while only white light showed a photon fluence dependency in I. tinctoria. These results suggest a different role played by the labile and stable phytochrome species (phyA and phyB) in the isatan B production in I. tinctoria and I. indigotica. I. indigotica, whose germination percentage was not influenced by light quality, demonstrated higher germination capability compared with I. tinctoria. In fact, I. tinctoria showed high frequency of germination in darkness and under light sources that establish high phytochrome photoequilibrium (red, white and yellow light). Germination in I. tinctoria was negatively affected by far red and blue light. I. indigotica seeds appear to be indifferent to canopy‐like light (far red). Our results provide further insights on the distinct behaviour of I. tinctoria and I. indigotica that belong to two different genetic clusters and different original environments.
14‐Fluoro‐Bacteriorhodopsin Gelation Films for Dynamic Holography Recording¶
Authors: Korchemskaya Elena , Burykin Nikolai , de Lera Angel , Alvarez Rosana , Pirutin Sergey , Druzhko Anna
Published: July 2010

The first dynamic holography recording using 14‐fluoro‐(14‐F) bacteriorhodopsin (BR) gelatin films has been achieved. 14‐F BR is an artifical BR pigment made by reconstitution of bacterioopsin (native BR without chromophore) with synthetic 14‐F ratinal. Low‐intensity red light from a cw HE‐Ne laser was used for dynamic holography recording on the 14‐F wild type (WT) BR and 14‐F D96N mutant BR in gelatin films. There is not true comparing the diffraction efficiency for 14‐F D96N BR and 14‐F WT gelatin film, unlike the increase diffraction efficiency for D96N BR gelation film with native chromphore relative to the WT BR gelatin film with native chromophore. Pre‐illumination with blue light of the 14‐F BR gelatin films significantly increases the differaction effciency of both the the 14‐F WT and the 14‐F D96N BR pigments. The sequential application of blue and red laser beams indicates that 14‐F WT and the 14‐F D96N BR pigments. The sequential application of blue and red laser beams indicates taht 14‐F BR gelation films can be useful for optical memory.
Sun‐reactive Skin Type in 4912 French Adults Participating in the SU.VI.MAX Study¶
Authors: Guinot Christiane , Malvy Denis J.‐M. , Latreille Julie , Ezzedine Khaled , Galan Pilar , Tenenhaus Michel , Ambroisine Laurence , Hercberg Serge , Tschachler Erwin
Published: July 2010

Phototype classifications were initially developed in an attempt to predict the skin reactions of patients to phototherapy and are now widely used to advise individuals with regard to sun protection. A transversal study was conducted on the SU.VI.MAX cohort to estimate the frequency of sunreactive skin features in a large, general adult population‐based sample, and to describe the associations between these features. The data were collected 3 years after the beginning of the SU.VI.MAX nutritional intervention study on 4912 volunteers (2868 women aged 35–60 years and 2044 men aged 45–60 years). A multiple correspondence analysis was performed to study the associations between the features. The results showed that these features correspond to a one‐dimensional phenomenon, which allowed us to establish a score to summarize skin sensitivity to sun exposure. Furthermore, we found a link between gender and phototype using the Césarini classification (phototype IV: 37% of women, 47% of men). The analysis of the relationship with sun‐reactive skin features and the score revealed the same trend. Phenotypic evaluation appears to be a good estimator of skin sensitivity to sun exposure for clinical screening or for use in research, and is easy to collect at a lower cost. Moreover, the sun sensitivity difference between gender should be considered in education about photoprotection.
Protein Kinase C Epsilon Signals Ultraviolet Light‐induced Cutaneous Damage and Development of Squamous Cell Carcinoma Possibly Through Induction of Specific Cytokines in a Paracrine Mechanism¶
Authors: Wheeler D. L. , Li Y. , Verma Ajit K.
Published: July 2010

Protein kinase C (PKC), a family of phospholipid‐dependent serine/threonine kinases, is not only the major intracellular receptor for the mouse skin tumor promoter 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) but also is activated by a variety of stress factors including ultraviolet radiation (UVR). PKCɛ is among six isoforms (α, δ, ɛ, η, μ and ζ) expressed in the mouse skin. To determine the in vivo functional specificity of PKCɛ in mouse skin carcinogenesis, we generated PKCɛ transgenic mouse (FVB/N) lines 224 and 215 that overexpress PKCɛ protein approximately 8‐ and 18‐fold, respectively, over endogenous levels in the basal epidermal cells and cells of the hair follicle. PKCɛ transgenic mice were observed to be highly sensitive to the development of papilloma‐independent metastatic squamous cell carcinoma (mSCC) elicited either by repeated exposure to UVR or by the 7,12‐Dimethylbenzanthracene–TPA tumor promotion protocol. The development of squamous cell carcinoma (SCC) appears to be linked to the PKCɛ‐mediated induction of cytokine tumor necrosis factor–α(TNFα). Immunohistochemical analysis for the expression of PKCɛ in the SCC of PKCɛ transgenic mice revealed that PKCɛ was not expressed in the tumor itself; however, the uninvolved tissue surrounding the SCC exhibited intense PKCɛ expression. Also, human SCC, similar to mouse SCC, did not express PKCɛ in the tumor, whereas the surrounding uninvolved epidermis revealed strong PKCɛ expression. These findings in both the PKCɛ mouse model and human SCC indicate that overexpression of PKCɛ in epidermis may lead to a microenvironment, which is suitable for enhancing the development of mSCC by a paracrine mechanism involving specific cytokines including TNFα.
Reconstruction of DNA Repair–deficient Xeroderma Pigmentosum Skin In Vitro: A Model to Study Hypersensitivity to UV Light¶
Authors: Bernerd Françoise , Asselineau Daniel , Frechet Mathilde , Sarasin Alain , Magnaldo Thierry
Published: July 2010

Xeroderma pigmentosum (XP) is a rare, recessive, photosensitive and cancer‐prone syndrome, the biochemical hallmark of which is a defect in nucleotide excision repair of ultraviolet (UV)–induced mutagenic lesions. After isolation and amplification of several strains of XP‐C keratinocytes and fibroblasts, a three‐dimensional skin model in vitro comprising both epidermis and a dermal equivalent could be obtained. XP dermal tissues and XP epidermis displayed specific morphological and biochemical characteristics compared with tissues obtained with normal cells. One of the major features was the formation of epidermal invaginations into the dermal equivalent. After UV‐B exposure, and contrary to repair of DNA lesions in normal cells, the XP model displayed repair deficiency with long‐lasting persistence of UV‐induced DNA damage and p53 positive nuclei. Recent data obtained after genetic correction leading to functional XPC gene in keratinocytes and fibroblasts revealed that several abnormal features could be normalized. In conclusion, reconstruction of XP skin in vitro provides a very promising system to study genetic hyperphotosensitivity and opens a rational perspective to XP tissue therapy.
Assessment of Cutaneous Photosensitivity of TOOKAD (WST09) in Preclinical Animal Models and in Patients¶
Authors: Weersink Robert A. , Forbes Jason , Bisland Stuart , Trachtenberg John , Elhilali Mostafa , Brún Pierre H. , Wilson Brian C.
Published: July 2010

TOOKAD (WST09) is a new, long‐wavelength palladium bacteriopheophorbide photosensitizer that targets tissue vasculature. The cutaneous phototoxicity of TOOKAD was assessed in normal rat and pig animal models and in patients in a Phase‐I trial of TOOKAD‐mediated photodynamic therapy (PDT) for recurrent prostate cancer. Controlled skin exposures were administered using solar‐simulated light at various times after drug administration. Two different spectral ranges were used. In the first, the UV portion of the spectrum was removed (UV−) because UV irradiation in nondrugged control animals produced an erythema response at incident energy densities (J/cm2) lower than those required to induce a PDT response. In the second, the full solar spectrum (UV+) was used, and the potentiation by the photosensitizer of the UV‐mediated minimum erythema dose was assessed. Results showed that the PDT skin response was negligible at clinical drug doses of 2 mg/kg for any period after administration at light doses of 128 J/cm2 in the animal models. In patients, there was no observed UV− skin response at doses of up to 2 mg/kg, drug–light intervals of 1–3 h or greater and light exposures up to 128 J/cm2. At higher drug doses in the rat and pig models, the duration of skin phototoxicity was found to be ∼3 h and less than 1 h, respectively. Using the full spectrum of solar‐simulated light, the presence of TOOKAD did not measurably enhance the UV+‐induced erythema in the rats, pigs or patients.
Multiplex Polymerase Chain Reaction Analysis of UV‐A– and UV‐B–induced Delayed and Early Mutations in V79 Chinese Hamster Cells¶
Authors: Dahle Jostein , Noordhuis Paul , Stokke Trond , Svendsrud Debbie Hege , Kvam Egil
Published: July 2010

We previously reported that approximately 10% of V79 Chinese hamster fibroblast populations clonally derived from single cells immediately after irradiation with either ultraviolet B (UV‐B, 290–320 nm, mainly 311 nm) or ultraviolet A (UV‐A, 320–400 nm, mainly 350–390 nm) radiation exhibit genomic instability. The instability is revealed by relatively high mutation frequencies in the hypoxanthine phosphoribosyl transferase (hprt) gene up to 23 cell generations after irradiation. These delayed mutant clones exhibited higher levels of oxidative stress than normal cells. Therefore, persistently increased oxidative stress has been proposed as a mechanism for UV‐induced genomic instability. This study investigates whether this mechanism is reflected in the deletion spectrum of delayed mutant clones. Eighty‐eight percent of the delayed mutant clones derived from UV‐A–irradiated populations were found to have total deletion of the hprt gene. Correspondingly, 81% of UV‐A–induced early mutations (i.e. detected shortly after irradiation) also had total deletions. Among delayed UV‐B–induced mutant clones, 23% had total deletions and 8% had deletion of one exon, whereas all early UV‐B events were either point mutations or small deletions or insertions. In conclusion, the multiplex polymerase chain reaction deletion screen showed that there were explicit differences in the occurrence of large gene alterations between early and delayed mutations induced by UV‐B radiation. For UV‐A radiation the deletion spectra were similar for delayed and early mutations. UV‐A radiation is, in contrast to UV‐B radiation, only weakly absorbed by DNA and probably induces mutation almost solely via production of reactive oxygen species. Therefore, the present results support the hypothesis that persistent increase in oxidative stress is involved in the mechanism of UV‐induced genomic instability.
Photochemistry of Phytoalexins Containing Phenalenone‐like Chromophores: Photophysics and Singlet Oxygen Photosensitizing Properties of the Plant Oxoaporphine Alkaloid Oxoglaucine¶
Authors: Flors Cristina , Prat Chantal , Suau Rafael , Nájera Francisco , Nonell Santi
Published: July 2010

Oxoglaucine (OG) is an oxoaporphine alkaloid, which has been linked to plant defense mechanisms. It contains a phenalenone (PN)–like chromophore, which suggests a role as singlet oxygen (1O2) photosensitizer. Indeed, OG is able to photosensitize 1O2 with 100% efficiency in nonpolar environments, similar to PN. However, this efficiency decreases in polar and protic media, although 1O2 is formed in all environments ranging from benzene to water. OG is a rather inefficient 1O2 quencher (kq= 8 × 105M−1 s−1) unlike the related alkaloids boldine and glaucine, for which an antioxidant role has been suggested. The results of this study contribute to the view that plant defense mediated by PN‐like secondary metabolites may have a photochemical component.
PhotochemCAD 2: A Refined Program with Accompanying Spectral Databases for Photochemical Calculations¶
Authors: Dixon James M. , Taniguchi Masahiko , Lindsey Jonathan S.
Published: July 2010

The PhotochemCAD program has been revised extensively. Calculations can be performed using eight modules (oscillator strength, transition dipole moment and natural radiative lifetime, Förster energy transfer, multicomponent analysis, blackbody radiator, artificial spectrum creation, transmission calculation, and analysis of energy transfer among linear multichromophore arrays). The user interface has been streamlined to facilitate visual display, operation of the various modules, input of user data via a wizard and output of spectra and calculations. The database of absorption and fluorescence spectra has been expanded to 150 photochemically relevant compounds. A database of solar spectra has been added. The program runs under Windows and is equipped with extensive literature references and help features, including a tutorial section with video files.
Photobleaching of Melanosomes from Retinal Pigment Epithelium: II. Effects on the Response of Living Cells to Photic Stress
Authors: Zareba Mariusz , Sarna Tadeusz , Szewczyk Grzegorz , Burke Janice M.
Published: July 2010

Melanosomes of the retinal pigment epithelium (RPE) are long lived organelles that may undergo photobleaching with aging, which can diminish the antioxidant efficiency of melanin. Here, isolated porcine RPE melanosomes were experimentally photobleached with visible light to simulate aging and compared with untreated granules or control particles (black latex beads) for their effects on the survival of photically stressed ARPE‐19 cultures. Particles were delivered to cultures for uptake by phagocytosis then cells were exposed to violet light and analyzed by a new live cell imaging method to identify the time of apoptotic blebbing as a dynamic measure of reduced cell survival. Results indicated that untreated melanosomes did not decrease photic injury to ARPE‐19 cells when compared with cells lacking particles or with cells containing control particles, as might be expected if melanin performed an antioxidant function. Instead cells with untreated melanosomes showed reduced survival indicated by an earlier onset of blebbing and a lower fraction of surviving cells after photic stress. Cell survival was reduced even further in stressed cells containing melanosomes that were photobleached, and survival decreased with increasing photobleaching time. Photobleaching of RPE melanosomes therefore makes cells containing them more sensitive to light‐induced cytotoxicity. This observation raises the possibility that aged melanosomes increase RPE cell photic stress in situ, perhaps contributing to reduced tissue function and to degeneration of the adjacent retina that the RPE supports. How melanosomes (photobleached or not) interact with their local subcellular environment to modify RPE cell survival is poorly understood and is likely determined by the physicochemical state of the granule and its constituent melanin. The live cell imaging method introduced here, which permitted detection of a graded effect of photobleaching, provides a sensitive bioassay for probing the effects of melanosome modifications.
Determination of Wavelength‐Specific UV Protection Factors of Sunscreens in Intact Skin by EPR Measurement of UV‐Induced Reactive Melanin Radical
Authors: Lund Leslie , Ley Ronald D. , Felton Linda A. , Timmins Graham S.
Published: July 2010

There remains an unmet need for skin tissue‐based assays for the measurement of the UVA protection and efficacy of sunscreens. Here we describe development of a novel electron paramagnetic resonance assay that uses the photogeneration of reactive melanin radical as a measure of UV light penetration to melanocytes in situ in skin. We have used areas of focal melanocytic hyperplasia in the skin of Monodelphis domestica to model the human nevus. We show that we are able to use this assay to determine the monochromatic protection factors (mPF) of research and commercial sunscreens at specific narrow wavebands of UVB, UVA and blue visible light. Both commercial sunscreens, a sun protection factor (SPF) 4 and an SPF 30 product, had mPFs in the UVB range that correlated well with their claimed SPF. However, their mPF in the UVA ranges were only about one‐third of claimed SPF. This technique can be used to design and assay sunscreens with optimally balanced UVA and UVB protection.
Motility of Daphnia spinulata as Affected by Solar Radiation Throughout an Annual Cycle in Mid‐latitudes of Patagonia†
Authors: Gonçalves Rodrigo J. , Barbieri Elena S. , Villafañe Virginia E. , Helbling E. Walter
Published: July 2010

During an annual cycle, Daphnia spinulata collected from a plankton community of Patagonia was exposed outdoors to assess the impact of recently received solar radiation on motility (i.e. swimming speed and gravitaxis). Individual values of these parameters were obtained by video recordings and image analysis at different time intervals during the day. Initial swimming speed varied throughout the year, and changes in speed during exposure were not significantly affected by any waveband used in our experimental design (i.e. PAB, 280–700 nm; PA, 320–700 nm; and P, 400–700 nm). Overall, most of the individuals swam downwards, regardless of the radiation treatment imposed to the samples. We found that multifactor interactions (i.e. not a single parameter explained more than 40% of the observed variability) explained most of our observations on motility parameters. These factors include not only solar radiation, but other physical (underwater radiation field and wind intensity) and biological parameters (food availability, presence of predators and congeners). Our findings indicate that the plankton dynamics in the study site is likely to be governed by a sum of factors which must be taken into account when considering solar radiation effects on aquatic ecosystems.
PAR and UV Effects on Vertical Migration and Photosynthesis in Euglena gracilis†
Authors: Richter Peter , Helbling Walter , Streb Christine , Häder Donat‐P.
Published: July 2010

Recently it was shown that the unicellular flagellate Euglena gracilis changes the sign of gravitaxis from negative to positive upon excessive radiation. This sign change persists in a cell culture for hours even if subsequently transferred to dim light. To test the ecological relevance of this behavior, a vertical column experiment was performed (max. depth 65 cm) to test distribution, photosynthetic efficiency and motility in different horizons of the column (surface, 20, 40 and 65 cm). One column was covered with a UV cut‐off filter, which transmits photosynthetically active radiation (PAR) only, the other with a filter which transmits PAR and UV. The columns were irradiated with a solar simulator (PAR 162 W m−2, UV‐A 32.6 W m−2, UV‐B 1.9 W m−2). The experiment was conducted for 10 days, normally with a light/dim light cycle of 12 h:12 h, but in some cases the light regime was changed (dim light instead of full radiation). Under irradiation the largest fraction of cells was found at the bottom of the column. The cell density decreased toward the surface. Photosynthetic efficiency, determined with a pulse amplitude modulated fluorometer, was negligible at the surface and increased toward the bottom. While the cell suspension showed a positive gravitaxis at the bottom, the cells in the 40 cm horizon were bimodally oriented (about the same percentage of cells swimming upward and downward, respectively). At 20 cm and at the surface the cells showed negative gravitaxis. Positive gravitaxis was more pronounced in the UV + PAR samples. At the surface and in the 20 and 40 cm horizons photosynthetic efficiency was better in the PAR‐only samples than in the PAR + UV samples. At the bottom photosynthetic efficiency was similar in both light treatments. The data suggest that high light reverses gravitaxis of the cells, so that they move downward in the water column. At the bottom the light intensity is lower (attenuation of the water column and self shading of the cells) and the cells recover. After recovery the cells swim upward again until the negative gravitaxis is reversed again.
“I'M A Firebug, Lady”
Authors: Macpherson Charlene
Published: July 2010

Editorial Comment: Your Editor unblushingly, and with some pride, confesses that he lifted the article which follows from the April issue of THE BULLETIN, official publication of the WOMEN'S CLUB OF UPPER MONTCLAIR, is located nearabout the city of Newark, New Jersey.

Now Newark is the place where Harry W. Lindeman and Horace S. Bellejato hold Court and dispense parental justice to children of that large city who go astray or are neglected.

They figure prominently (and properly) in the article.

Also is mentioned our immediate past president, G. Bowdon Hunt, who gave with some quotable quotes. Moreover there is much about the Day in Court and pioneer adventures, such as Highfields, the Community Adjustment Conference and other fruits, mainly of the leadership of the two judges of this area mentioned above.

Another thing: Charlene MacPherson, Director, Public Affairs, is a superlative writer.

The Editorial Pride first mentioned arises from the fact that the Editor believes he knows good writing when he sees it. He also thinks he knows good judges.

Just this last comment: if purloining this piece is larceny in any degree the defendant editor is willing to make a pauper's oath as to his indigency and ignorance.

Now read, “I'M A FIREBUG, LADY.”
Use of Logistic Regression for Prediction of the Fate of
Staphylococcus aureus
in Pasteurized Milk in the Presence of Two Lytic Phages
Authors: Obeso José M. , García Pilar , Martínez Beatriz , Arroyo-López Francisco Noé , Garrido-Fernández Antonio , Rodriguez Ana
Published: July 2010

The use of bacteriophages provides an attractive approach to the fight against food-borne pathogenic bacteria, since they can be found in different environments and are unable to infect humans, both characteristics of which support their use as biocontrol agents. Two lytic bacteriophages, vB_SauS-phiIPLA35 (phiIPLA35) and vB_SauS-phiIPLA88 (phiIPLA88), previously isolated from the dairy environment inhibited the growth of
Staphylococcus aureus
. To facilitate the successful application of both bacteriophages as biocontrol agents, probabilistic models for predicting
S. aureus
inactivation by the phages in pasteurized milk were developed. A linear logistic regression procedure was used to describe the survival/death interface of
S. aureus
after 8 h of storage as a function of the initial phage titer (2 to 8 log
10
PFU/ml), initial bacterial contamination (2 to 6 log
10
CFU/ml), and temperature (15 to 37°C). Two successive models were built, with the first including only data from the experimental design and a global one in which results derived from the validation experiments were also included. The temperature, interaction temperature-initial level of bacterial contamination, and initial level of bacterial contamination-phage titer contributed significantly to the first model prediction. However, only the phage titer and temperature were significantly involved in the global model prediction. The predictions of both models were fail-safe and highly consistent with the observed
S. aureu
s responses. Nevertheless, the global model, deduced from a higher number of experiments (with a higher degree of freedom), was dependent on a lower number of variables and had an apparent better fit. Therefore, it can be considered a convenient evolution of the first model. Besides, the global model provides the minimum phage concentration (about 2 × 10
8
PFU/ml) required to inactivate
S. aureus
in milk at different temperatures, irrespective of the bacterial contamination level.
Transcriptional Regulation of the Terephthalate Catabolism Operon in
Comamonas
sp. Strain E6
Authors: Kasai Daisuke , Kitajima Masahiro , Fukuda Masao , Masai Eiji
Published: July 2010

Two almost identical gene clusters,
tphR
I
C
I
A2
I
A3
I
B
I
A1
I
and
tphR
II
C
II
A2
II
A3
II
B
II
A1
II
, are responsible for the conversion of terephthalate (TPA) to protocatechuate in
Comamonas
sp. strain E6. In the present study, we investigated the transcriptional regulation of the
tphR
II
C
II
A2
II
A3
II
B
II
A1
II
gene cluster. Reverse transcription-PCR analysis suggested that the
tphR
II
C
II
A2
II
A3
II
B
II
A1
II
genes form two transcriptional units, the
tphC
II
A2
II
A3
II
B
II
A1
II
catabolism operon and
tphR
II
, with the latter encoding an IclR-type transcriptional regulator (ITTR). The transcription start site of the
tph
II
catabolism operon was mapped at 21 nucleotides upstream of the initiation codon of
tphC
II
. The
lacZ
transcriptional fusion experiments showed that
tphR
II
encodes a transcriptional activator of the
tph
II
catabolism operon and that TPA acts as an inducer. On the other hand, TphR
II
appeared to repress its own transcription regardless of the presence of TPA. The analysis of mutant derivatives of E6 indicated that
tphR
II
is essential for the transcriptional activation of the
tph
II
catabolism operon and the growth on TPA of a
tph
I
-deficient derivative of E6. Purified His-tagged TphR
II
bound specifically to the
tphR
II
-
tphC
II
intergenic region containing a 21-bp inverted repeat sequence. Alignment of the inverted repeat sequences in the binding sites for TphR
II
and other members of ITTRs revealed highly conserved nucleotides. The substitution of conserved nucleotides resulted in significantly reduced TPA-dependent transcriptional activation from the
tphC
II
promoter and reduced binding to His-tagged TphR
II
. These results clearly indicate that the conserved nucleotides are required for the inducible expression of the
tph
II
catabolism operon regulated by TphR
II
.
Use of Amino Acids as Inducers for High-Level Protein Expression in the Single-Protein Production System
Authors: Vaiphei S. Thangminlal , Mao Lili , Shimazu Tsutomu , Park Jung-Ho , Inouye Masayori
Published: July 2010

By taking advantage of MazF, an ACA codon-specific mRNA interferase,
Escherichia coli
cells can be converted into a bioreactor producing only a single protein of interest by using an ACA-less mRNA for the protein. In this single-protein production (SPP) system, we engineered MazF by replacing two tryptophan residues in positions 14 and 83 with Phe (W14F) and Leu (W83L), respectively. Upon the addition of an inducer (IPTG [isopropyl-β-
d
-thiogalactopyranoside]), the mutated MazF [MazF(ΔW)] can still be produced even in the absence of tryptophan in the medium by using a Trp auxotroph, while a target protein having Trp residues cannot be produced. However, at 3 h after the addition of IPTG, the addition of tryptophan to the medium exclusively induces production of the target protein at a high level. A similar SPP system was also constructed with the use of a His-less protein [MazF(ΔH)] and a His auxotroph. Using these dual-induction systems, isotopic enrichments of
13
C,
15
N, and
2
H were highly improved by almost complete suppression of the production of the unlabeled target protein. In both systems, isotopic incorporation reached more than 98% labeling efficiency, significantly reducing the background attributable to the unlabeled target protein.
Validation of a Self-Excising Marker in the Human Pathogen
Aspergillus fumigatus
by Employing the β-Rec/
six
Site-Specific Recombination System
Authors: Hartmann Thomas , Dümig Michaela , Jaber Basem M. , Szewczyk Edyta , Olbermann Patrick , Morschhäuser Joachim , Krappmann Sven
Published: July 2010

Recyclable markers based on site-specific recombination allow repetitive gene targeting in filamentous fungi. Here we describe for the first time functionality of the bacterial recombination system employing β serine recombinase acting on
six
recognition sequences (β-rec/
six
) in a fungal host, the human pathogen
Aspergillus fumigatus
, and its use in establishing a self-excising resistance marker cassette for serial gene replacement.
Chitin Utilization by the Insect-Transmitted Bacterium
Xylella fastidiosa
Authors: Killiny Nabil , Prado Simone S. , Almeida Rodrigo P. P.
Published: July 2010

Xylella fastidiosa
is an insect-borne bacterium that colonizes xylem vessels of a large number of host plants, including several crops of economic importance. Chitin is a polysaccharide present in the cuticle of leafhopper vectors of
X. fastidiosa
and may serve as a carbon source for this bacterium. Biological assays showed that
X. fastidiosa
reached larger populations in the presence of chitin. Additionally, chitin induced phenotypic changes in this bacterium, notably increasing adhesiveness. Quantitative PCR assays indicated transcriptional changes in the presence of chitin, and an enzymatic assay demonstrated chitinolytic activity by
X. fastidiosa
. An ortholog of the chitinase A gene (
chiA
) was identified in the
X. fastidiosa
genome. The
in silico
analysis revealed that the open reading frame of
chiA
encodes a protein of 351 amino acids with an estimated molecular mass of 40 kDa.
chiA
is in a locus that consists of genes implicated in polysaccharide degradation. Moreover, this locus was also found in the genomes of closely related bacteria in the genus
Xanthomonas
, which are plant but not insect associated.
X. fastidiosa
degraded chitin when grown on a solid chitin-yeast extract-agar medium and grew in liquid medium with chitin as the sole carbon source; ChiA was also determined to be secreted. The gene encoding ChiA was cloned into
Escherichia coli
, and endochitinase activity was detected in the transformant, showing that the gene is functional and involved in chitin degradation. The results suggest that
X. fastidiosa
may use its vectors' foregut surface as a carbon source. In addition, chitin may trigger
X. fastidiosa's
gene regulation and biofilm formation within vectors. Further work is necessary to characterize the role of chitin and its utilization in
X. fastidiosa
.
Effect of Earthworm Feeding Guilds on Ingested Dissimilatory Nitrate Reducers and Denitrifiers in the Alimentary Canal of the Earthworm
Authors: Depkat-Jakob Peter S. , Hilgarth Maik , Horn Marcus A. , Drake Harold L.
Published: July 2010

The earthworm gut is an anoxic nitrous oxide (N2O)-emitting microzone in aerated soils.In situconditions of the gut might stimulate ingested nitrate-reducing soil bacteria linked to this emission. The objective of this study was to determine if dissimilatory nitrate reducers and denitrifiers in the alimentary canal were affected by feeding guilds (epigeic [Lumbricus rubellus], anecic [Lumbricus terrestris], and endogeic [Aporrectodea caliginosa]). Genes and gene transcripts ofnarG(encodes a subunit of nitrate reductase and targets both dissimilatory nitrate reducers and denitrifiers) andnosZ(encodes a subunit of N2O reductase and targets denitrifiers) were detected in guts and soils. Gut-derived sequences were similar to those of cultured and uncultured soil bacteria and to soil-derived sequences obtained in this study. Gut-derivednarGsequences andnarGterminal restriction fragments (TRFs) were affiliated mainly with Gram-positive organisms (Actinobacteria). The majority of gut- and uppermost-soil-derivednarGtranscripts were affiliated withMycobacterium(Actinobacteria). In contrast,narGsequences indicative of Gram-negative organisms (Proteobacteria) were dominant in mineral soil. MostnosZsequences andnosZTRFs were affiliated withBradyrhizobium(Alphaproteobacteria) and uncultured soil bacteria. TRF profiles indicated thatnosZtranscripts were more affected by earthworm feeding guilds than werenosZgenes, whereasnarGtranscripts were less affected by earthworm feeding guilds than werenarGgenes.narGandnosZtranscripts were different and less diverse in the earthworm gut than in mineral soil. The collective results indicate that dissimilatory nitrate reducers and denitrifiers in the earthworm gut are soil derived and that ingestednarG- andnosZ-containing taxa were not uniformly stimulated in the guts of worms from different feeding guilds.