bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Spatial Distribution of Optical Properties in the Ultraviolet and Visible in an Aquatic Ecosystem¶
Authors: Bracchini Luca , Loiselle Steven , Dattilo Arduino Massimo , Mazzuoli Stefania , Cózar Andrés , Rossi Claudio 
Published: July 2010

ABSTRACTIn aquatic ecosystems, the UV and visible radiation environment is strongly influenced by variation in the chemical and physical parameters of the ecosystems. In shallow lakes, highly heterogeneous water characteristics produce a wide variety of optical environments. Such ecosystems require analysis approaches that consider a potential variability. In this study, 77 stations were used to characterize the optical properties of a shallow lake (open water surface 54 km2). The vertical attenuation of solar radiation at 305,313,320 and 340 nm and at photosynthetically active radiation was measured during the seasonal cycle. Dissolved organic matter (DOM), turbidity, fluorescence, pH, temperature, conductance and dissolved oxygen were simultaneously measured. The spatial variation of the extinction spectra of the dissolved fraction at each sampling station was also measured and analyzed between 270 and 400 nm. The spatial heterogeneity of the lake was examined by determining the distributions of the attenuation coefficients and biooptical parameters at high spatial resolution and describing the distributions in a series of maps. The methodology permitted a quantitative description of the interaction between solar radiation and aquatic ecosystems as well as a spatial classification of the dominating processes within the lake. This included the determination of the role played by DOM loading and changing chemical properties within the lake optical environment.
Binding, aggregation and photochemical properties of methylene blue in mitochondrial suspensions
Authors: Gabrielli Dino , Belisle Eduardo , Severino Divinomar , Kowaltowski Alicia J. , Baptista Mauricio S. 
Published: July 2010

AbstractMethylene Blue (MB) has well‐established photochemical properties and has been used in a variety of photochemical applications including photodynamic therapy. Despite the fact that most of MB's cytotoxic effects in cells are attributed to mitochondrial damage, the interactions of this dye with mitochondria and the consequent effects on photochemical properties have not yet been fully determined. We monitored MB binding, aggregation and its ability to release singlet oxygen (1O2) on irradiation when interacting with mitochondrial suspensions. MB actively binds to mitochondria and enters the matrix in a manner stimulated by the mitochondrial proton potential and by the increase in mitochondrial concentrations. The greater accumulation of MB in mitochondria with elevated proton potentials or those treated with high concentrations of MB results in the formation of MB dimers, previously shown to be less effective generators of 1O2. Accumulation of MB within mitochondria with high membrane potentials also results in the reduction of MB to the photochemically inactive leuco‐MB. Indeed, irradiation of mitochondria with high proton potentials in the presence of MB results in the generation of approximately half the quantity of 1O2 compared with 1O2 generated in mitochondria with low proton potentials. These differences in photochemical properties should influence the cytotoxic effects of photodynamic treatment in the presence of MB.
Photodynamic Characterization and In Vitro Application of Methylene Blue‐containing Nanoparticle Platforms¶
Authors: Tang Wei , Xu Hao , Kopelman Raoul , Philbert Martin A. 
Published: July 2010

ABSTRACTThis article presents the development and characterization of nanoparticles loaded with methylene blue (MB), which are designed to be administered to tumor cells externally and deliver singlet oxygen (1O2) for photodynamic therapy (PDT), i.e. cell kill via oxidative stress to the membrane. We demonstrated the encapsulation of MB, a photosensitizer (PS), in three types of sub‐200 nm nanoparticles, composed of polyacrylamide, sol‐gel silica and organically modified silicate (ORMOSIL), respectively. Induced by light irradiation, the entrapped MB generated 1O2), and the produced 1O2 was measured quantitatively with anthracene‐9, 10‐dipropionic acid, disodium salt, to compare the effects of different matrices on 1O2 delivery. Among these three different kinds of nanoparticles, the polyacrylamide nanoparticles showed the most efficient delivery of 1O2 but its loading of MB was low. In contrast, the sol‐gel nanoparticles had the best MB loading but the least efficient 1O2 delivery. In addition to investigating the matrix effects, a preliminary in vitro PDT study using the MB‐loaded polyacrylamide nanoparticles was conducted on rat C6 glioma tumor cells with positive photodynamic results. The encapsulation of MB in nanoparticles should diminish the interaction of this PS with the biological milieu, thus facilitating its systemic administration. Furthermore, the concept of the drug‐delivering nanoparticles has been extended to a new type of dynamic nanoplatform (DNP) that only delivers 1O2. This DNP could also be used as a targeted multifunctional platform for combined diagnostics and therapy of cancer.
WST11, A Novel Water‐soluble Bacteriochlorophyll Derivative; Cellular Uptake, Pharmacokinetics, Biodistribution and Vascular‐targeted Photodynamic Activity Using Melanoma Tumors as a Model¶
Authors: Mazor Ohad , Brandis Alexander , Plaks Vicki , Neumark Eran , Rosenbach‐Belkin Varda , Salomon Yoram , Scherz Avigdor 
Published: July 2010

ABSTRACTWST11 is a novel negatively charged water‐soluble palladiumbacteriochlorophyll derivative that was developed for vascular‐targeted photodynamic therapy (VTP) in our laboratory. The in vitro results suggest that WST11 cellular uptake, clearance and phototoxicity are mediated by serum albumin trafficking. In vivo, WST11 was found to clear rapidly from the circulation (t1/2= 1.65 min) after intravenous bolus injection in the mouse, whereas a longer clearance time (t1/2= 7.5 min) was noted in rats after 20 min of infusion. The biodistribution of WST11 in mouse tissues indicates hepatic clearance (t1/2= 20 min), with minor (kidney, lung and spleen) or no intermediary accumulation in other tissues. As soon as 1 h after injection, WST11 had nearly cleared from the body of the mouse, except for a temporal accumulation in the lungs from which it cleared within 40 min. On the basis of these results, we set the VTP protocol for a short illumination period (5 min), delivered immediately after WST11 injection. On subjecting M2R melanoma xenografts to WST11‐VTP, we achieved 100% tumor flattening at all doses and a 70% cure with 9 mg/kg and a light exposure dose of 100 mW/cm2. These results provide direct evidence that WST11 is an effective agent for VTP and provide guidelines for further development of new candidates.
Effects of Short‐ and Long‐term Ultraviolet B Irradiation on the Immune System of the Common Carp (Cyprinus carpio)¶
Authors: Markkula S. Eveliina , Salo Harri M. , Immonen Anu K. , Jokinen E. Ilmari 
Published: July 2010

ABSTRACTCarp (Cyprinus carpio) were repeatedly exposed to 0, 60, 120 and 240 mJ/cm2 ultraviolet B (UVB) radiation three times in 1 week (short‐term exposure) or 12 times in 4 weeks (long‐term exposure). The effect of UVB on the functioning of the carp immune system was studied on day 2 after the final irradiation. After short‐term UVB exposure, the whole‐blood respiratory burst and cytotoxic activity were markedly enhanced, with parallel responses in both the number of circulating granulocytes and in the plasma cortisol concentration of the fish. These changes were not detectable after long‐term exposure. The respiratory burst by head kidney granulocytes was suppressed dose dependently after both exposures, but cytotoxic activity was not affected. Exposure to UVB also modulated lymphocyte functions: nonstimulated and PHA‐stimulated proliferation of head kidney lymphocytes in vitro was enhanced by both short‐term and long‐term exposure. LPS‐stimulated proliferation was not affected by exposure nor was the number of immunoglobulin‐secreting cells in the head kidney. In long‐term exposure, the highest dose reduced the level of plasma IgM. This study indicates that UVB irradiation induces immunomodulation in the blood and head kidney of the carp and that the effects of short‐ and long‐term exposure differ from each other. The results emphasize the potentially harmful impact of increased solar UVB radiation on fish immune functions.
Encuentros Latinoamericanos de Fotoquímica y Fotobiología (ELAFOT): The Latin‐American Photochemical and Photobiological Community¶
Authors: Braslavsky Silvia E. , Simon John D. 
Published: July 2010

ABSTRACTThe photochemical and photobiological researchers in Latin American meet biannually at a regional meeting known as Encuentros Latinoamericanos de Fotoquímica y Fotobiología (ELAFOT). The goals of this series of meetings are to discuss leading scientific work, to become acquainted with the latest research findings in the discipline, to exchange ideas, to initiate collaborations between groups and to strengthen the scientific interactions between young researchers and senior experts from the region and from developed countries. During 8–12 November 2004, the eighth such meeting took place in La Plata, Argentina. In this introduction we present a brief history of the ELAFOT meetings and a summary of the most recent gathering and the papers presented in this Symposium‐in‐Print.
Porphyrin‐fullerene C60 Dyads with High Ability to Form Photoinduced Charge‐separated State as Novel Sensitizers for Photodynamic Therapy¶
Authors: Milanesio M. Elisa , Alvarez M. Gabriela , Rivarola Viviana , Silber Juana J. , Durantini Edgardo N. 
Published: July 2010

ABSTRACTThe photodynamic activities of a porphyrin‐C60 dyad (P‐C60) and its metal complex with Zn(II) (ZnP‐C60) were compared with 5‐(4‐acetamidophenyl)‐10,15,20‐tris(4‐methoxyphenyl)‐porphyrin (P), both in homogeneous medium‐bearing photooxidizable substrates and in vitro on the Hep‐2‐human‐larynx‐carcinoma cell line. This study represents the first evaluation of dyads, with a high capacity to form a photoinduced charge‐separated state, to act as agents to inactivate cells by photodynamic therapy (PDT). Absorption and fluorescence spectroscopic studies were performed in toluene and N,N‐dimethylformamide (DMF). The emission of the porphyrin moiety in the dyads is strongly quenched by the attached fullerene C60 moiety. The singlet molecular oxygen, O2(1Δg), productions (φΔ) were determined using 9,10‐dimethylanthracene (DMA). The values of φΔ were strongly dependent on the solvent's polarity. Comparable φΔ values were found for dyads and P in toluene, while O2(1Δg) production was significantly diminished for the dyads in DMF. In more polar solvent, the stabilization of charge‐transfer state takes place, decreasing the efficiency of porphyrin triplet‐state formation. Also, both dyads photosensitize the decomposition of L‐tryptophan in DMF. In biological medium, no dark cytotoxicity was observed using sensitizer concentrations ≤1 μM and 24 h of incubation. The uptake of sensitizers into Hep‐2 was studied using 1 μM of sensitizer and different times of incubation. Under these conditions, a value of ∼1.5 nmol/106 cells was found between 4 and 24 h of incubation. The cell survival after irradiation of the cells with visible light was dependent upon light‐exposure level. A higher photocytotoxic effect was observed for P‐C60, which inactivates 80% of cells after 15 min of irradiation. Moreover, both dyads keep a high photoactivity even under argon atmosphere. Thus, depending on the microenvironment where the sensitizer is localized, these compounds could produce biological photodamage through either an O2(1Δg)‐mediated photoreaction process or a free‐radicals mechanism under low oxygen concentration. These results show that molecular dyads, which can form a photoinduced charge‐separated state, are a promising model for phototherapeutic agents, with potential applications in cell inactivation by PDT.
Confocal Fluorescence Imaging of Photosensitized DNA Denaturation in Cell Nuclei¶
Authors: Bernas Tytus , Asem Elikplimi K. , Robinson J. Paul , Cook Peter R. , Dobrucki Jurek W. 
Published: July 2010

ABSTRACTThe double‐stranded helical structure of DNA is maintained in part by hydrogen bonds between strands and by stacking interactions between adjacent purine and pyrimidine bases in one strand. The transition (denaturation) from a double‐stranded (ds) to a single‐stranded (ss) form can be induced in isolated DNA or fixed cells by exposure to elevated temperatures, alkali or acids, aprotic or nonpolar solvents or some drugs. We report here that DNA denaturation can occur in situ in cell nuclei as a result of interaction between light and an intercalated dye, acridine orange or ethidium bromide. This DNA photodenaturation was probed using metachromatic properties of acridine orange and imaged by fluorescence confocal microscopy. Furthermore, an empirical kinetic model was developed to separate changes of acridine orange luminescence intensities caused by photobleaching from those that were a result of DNA denaturation. We investigated the influence of oxygen on these phenomena and propose a mechanism by which photodenaturation may occur.
Optimization of DNA Extraction from a Scleractinian Coral for the Detection of Thymine Dimers by Immunoassay†
Authors: Banaszak Anastazia T. 
Published: July 2010

ABSTRACTUltraviolet (UV)‐B is known to cause DNA damage, principally by the formation of thymine dimers, but little research has been conducted in coral reef environments where UV doses are high. The majority of tropical reef‐dwelling corals form a mutualistic symbiosis with the dinoflagellateSymbiodiniumbut few studies have been conducted onin situDNA damage in corals and none have investigated the symbiotic components separately. The aim of this research was to quantify DNA damage in both the coral host and the dinoflagellate symbiont. The first step in this investigation was to optimize the extraction of DNA from the host,Porites astreoides, as well as the symbiont. The optimization was divided into a series of steps: the preservation of the samples, separation of the coral tissue from the skeleton, separation of the host tissue from the algal cells to prevent cross contamination as well as the extraction and purification of genomic DNA from the algae that are located intracellularly within the invertebrate animal tissue. The best preservation method was freezing at low temperatures without ethanol. After scraping with a razor blade, the coral tissue can be divided into host and algal components and the DNA extracted using modifications of published techniques yielding DNA suitable for the quantification of thymine dimer formation using antibodies. Preliminary data suggest that inP. astreoidescollected from 1 m depth, thymine dimers form approximately 2.8 times more frequently in the host DNA than in the DNA of its symbionts.
Reactions of Cl•/Cl2•− Radicals with the Nanoparticle Silica Surface and with Humic Acids: Model Reactions for the Aqueous Phase Chemistry of the Atmosphere
Authors: Caregnato Paula , Gara Pedro D. , Bosio Gabriela N. , Mártire Daniel O. , Gonzalez Mónica C. 
Published: July 2010

ABSTRACTReactions of chlorine radicals might play a role in aqueous aerosols where a core of inorganic components containing insulators such as SiO2 and dissolved HUmic‐LIke Substances (HULIS) are present. Herein, we report conventional flash photolysis experiments performed to investigate the aqueous phase reactions of silica nanoparticles (NP) and humic acid (HA) with chlorine atoms, Cl•, and dichloride radical anions, Cl2•−. Silica NP and HA may be taken as rough models for the inorganic core and HULIS contained in atmospheric particles, respectively. Both Cl• and Cl2•− were observed to react with the deprotonated silanols on the NP surface with reaction rate constants, k ± σ, of (9 ± 6) × 107 M−1 s−1 and (7 ± 4) × 105 M−1 s−1, respectively. The reaction of Cl• with the surface deprotonated silanols leads to the formation of SiO• defects. HA are also observed to react with Cl• and Cl2•− radicals, with reaction rate constants at pH 4 of (3 ± 2) × 1010 M−1 s−1 and (1.2 ± 0.3) × 109 M−1 s−1, respectively. The high values observed for these constants were discussed in terms of the multifunctional heterogeneous mixture of organic molecules conforming HA.
The Effect of Chronic Ultraviolet Radiation on the Human Immune System†
Authors: Norval Mary , McLoone Pauline , Lesiak Aleksandra , Narbutt Joanna 
Published: July 2010

AbstractA single or a limited number of UVR exposures is recognized to suppress cell‐mediated immunity in human subjects. The complex pathway leading from the absorption of photons by chromophores in the skin to the generation of T regulatory cells has been, at least partially, elucidated. However, the effect of repeated UV exposures on immune responses and associated mediators is not well studied, particularly to assess whether they lead, first, to the development of photoprotection so that these immune changes are reduced or no longer occur, and, secondly, to the development of photoprotection against the normal downregulation of immunity induced by a high UV dose. For almost all the parameters evaluated in this review—epidermal DNA damage/erythema, urocanic acid, Langerhans and dendritic cells, natural killer cells, macrophages, mast cells, contact and delayed hypersensitivity responses—none, aside from epidermal DNA damage/erythema and macrophage phagocytic activity, show convincing evidence of photoadaptation or, where appropriate, photoprotection. It is concluded that repeatedly irradiating individuals with UVR is likely to continue to result in downregulation of immunity.
Regulation of the
Marinomonas mediterranea
Antimicrobial Protein Lysine Oxidase by
l
-Lysine and the Sensor Histidine Kinase PpoS
Authors: Molina-Quintero Luisa R. , Lucas-Elío Patricia , Sanchez-Amat Antonio 
Published: July 2010

ABSTRACT

Some Gram-negative bacteria express a novel enzyme with lysine-ε-oxidase (LOD) activity (EC 1.4.3.20). The oxidation of
l
-Lys generates, among other products, hydrogen peroxide, which confers antimicrobial properties to this kind of enzyme and has been shown to be involved in cell death during biofilm development and differentiation. In addition to LOD, the melanogenic marine bacterium
Marinomonas mediterranea
, which forms part of the microbiota of the marine plant
Posidonia oceanica
, expresses two other oxidases of biotechnological interest, a multicopper oxidase, PpoA, with laccase activity and a tyrosinase named PpoB, which is responsible for melanin synthesis. By using both
lacZ
fusions with the
lodAB
promoter and quantitative reverse transcription-PCR (qRT-PCR), this study shows that the hybrid sensor histidine kinase PpoS regulates LOD activity at the transcriptional level. Although PpoS also regulates PpoA and PpoB, in this case, the regulatory effect cannot be attributed only to a transcriptional regulation. Further studies indicate that LOD activity is induced at the posttranscriptional level by
l
-Lys as well as by two structurally similar compounds,
l
-Arg and meso-2,6-diaminopimelic acid (DAP), neither of which is a substrate of the enzyme. The inducing effect of these compounds is specific for LOD activity since PpoA and PpoB are not affected by them. This study offers, for the first time, insights into the mechanisms regulating the synthesis of the antimicrobial protein lysine-ε-oxidase in
M. mediterranea
, which could be important in the microbial colonization of the seagrass
P. oceanica
.
Detection of New
cry
Genes of
Bacillus thuringiensis
by Use of a Novel PCR Primer System
Authors: Noguera Pedro A. , Ibarra Jorge E. 
Published: July 2010

ABSTRACT

On the basis of the known
cry
gene sequences of
Bacillus thuringiensis
, three sets of primers were designed from four conserved blocks found in the delta-endotoxin-coding region. The primer pairs designed amplify the regions between blocks 1 and 5, 2 and 5, and 1 and 4.
In silico
analyses indicated that 100% of the known three-domain
cry
gene sequences can be amplified by these sets of primers. To test their ability to amplify known and unknown
cry
gene sequences, 27 strains from the CINVESTAV (LBIT series) collection showing atypical crystal morphology were selected. Their DNA was used as the template with the new primer system, and after a systematic amplification and sequencing of the amplicons, each strain showed one or more
cry
-related sequences, totaling 54 different sequences harbored by the 27 strains. Seven sequences were selected on the basis of their low level of identity to the known
cry
sequences, and once cloning and sequencing of the complete open reading frames were done, three new
cry
-type genes (primary ranks) were identified and the toxins that they encode were designated Cry57Aa1, Cry58Aa1, and Cry59Aa1 by the
B. thuringiensis
Toxin Nomenclature Committee. The rest of the seven sequences were classified Cry8Ka2, Cry8-like, Cry20Ba1, and Cry1Ma1 by the committee. The crystal morphology of the selected strains and analysis of the new Cry protein sequences showed interesting peculiarities.
Quantitative PCR Assay for
Mycobacterium pseudoshottsii
and
Mycobacterium shottsii
and Application to Environmental Samples and Fishes from the Chesapeake Bay
Authors: Gauthier D. T. , Reece K. S. , Xiao J. , Rhodes M. W. , Kator H. I. , Latour R. J. , Bonzek C. F. , Hoenig J. M. , Vogelbein W. K. 
Published: July 2010

ABSTRACT

Striped bass (
Morone saxatilis
) in the Chesapeake Bay are currently experiencing a very high prevalence of mycobacteriosis associated with newly described
Mycobacterium
species,
Mycobacterium pseudoshottsii
and
M. shottsii.
The ecology of these mycobacteria outside the striped bass host is currently unknown. In this work, we developed quantitative real-time PCR assays for
M. pseudoshottsii
and
M. shottsii
and applied these assays to DNA extracts from Chesapeake Bay water and sediment samples, as well as to tissues from two dominant prey of striped bass, Atlantic menhaden (
Brevoortia tyrannus
) and bay anchovy (
Anchoa mitchilli
).
Mycobacterium pseudoshottsii
was found to be ubiquitous in water samples from the main stem of the Chesapeake Bay and was also present in water and sediments from the Rappahannock River, Virginia.
M. pseudoshottsii
was also detected in menhaden and anchovy tissues. In contrast,
M. shottsii
was not detected in water, sediment, or prey fish tissues. In conjunction with its nonpigmented phenotype, which is frequently found in obligately pathogenic mycobacteria of humans, this pattern of occurrence suggests that
M. shottsii
may be an obligate pathogen of striped bass.