bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE PHOTOCHEMISTRY OF ADENOSINE: INTERMEDIATES CONTRIBUTING TO ITS PHOTODEGRADATION MECHANISM IN AQUEOUS SOLUTION AT 298 K AND CHARACTERIZATION OF THE MAJOR PRODUCT
Authors: Arce Rafael , Marínez Lydia , Danielsen Edgard 
Published: January 2008

Abstract— The steady‐state (254 nm) photolysis of 9–(β‐d‐erythropentofuranosyl)adenine (adenosine) in aqueous solution was studied. Photodestruction yields on the order of 1.3 × 10−3) were determined at room temperature by measuring the initial decrease in the absorption maximum as a function of irradiation time. The use of high performance liquid chromatography (HPLC) permitted a more exact determination of the yield (2.5 × 103). The formation of photoproducts was also studied using HPLC. In the photolysis of 50 μM aqueous solutions of adenosine under anaerobic conditions at least 11 stable photoproducts are formed that absorb at 260 nm, the wavelength of maximum absorption of adenosine. The major photoproduct was also isolated and characterized as adenine; its formation yield was determined to be 4.5 × 104. This yield is affected by the presence of oxygen and by the initial concentration of adenosine employed. Fluorescence emission and excitation spectra were used to monitor the formation of highly fluorescent photoproducts that emit with maxima at365, 398, and 430 nm and absorb in the wavelength region of 240–380 nm.The reactive species in the photodestruction mechanism were established using substrates that react selectively with the respective short‐lived species. Photoionization is a primary photoprocess implied by these studies. The triplet state of adenosine also contributes to the photodestruction mechanism.
PHOTODYNAMIC THERAPY OF B16 PIGMENTED MELANOMA WITH LIPOSOME‐DELIVERED Si(IV)‐NAPHTHALOCYANINE
Authors: Biolo Roberta , Jori Giulio , Soncin Marina , Pratesi Riccardo , Vanni Umberto , Rihter Boris , Kenney Malcom E. , Rodgers Michael A. J. 
Published: January 2008

AbstractThe possibility of extending photodynamic therapy to the treatment of highly pigmented neoplastic lesions was tested by using Si(IV)‐naphthalocyanine (SiNc) as a tumor‐localizing agent. Si(IV)‐naphthalocyanine displays intense absorbance at 776 nm (ɛ= 5 × 105 M−1 cm−1), where melanin absorption becomes weaker. As an experimental model we selected B16 pigmented melanoma subcutaneously transplanted to C57BL mice. Upon injection of 0.5 or 1 mg kg−1 of liposome‐incorporated SiNc, maximal accumulation of the photosensitizer in the tumor was observed at 24 h with recoveries of 0.35 and 0.57 μg g−1, respectively. However, the tumor targeting by SiNc shows essentially no selectivity, since the photosensitizer concentrations in the skin (peritumoral tissue) were very similar to those found in the tumor at all postinjection times examined by us. Irradiation of SiNc‐loaded melanoma with 776 nm light from a diode laser at 24 h postinjection induces tumor necrosis and delay of tumor growth. The effect appears to be of purely photochemical nature at dose rates up to 260 mW cm−2; at higher dose rates, thermal effects are likely to become important.
THE Arabidopsis PHYTOCHROME A GENE HAS MULTIPLE TRANSCRIPTION START SITES AND A PROMOTER SEQUENCE MOTIF HOMOLOGOUS TO THE REPRESSOR ELEMENT OF MONOCOT PHYTOCHROME A GENES
Authors: Dehesh Katayoon , Franci Chris , Sharrock Robert A. , Somers David E. , Welsch Jo Anne , Quail Peter H. 
Published: January 2008

AbstractWe have determined the sequence of the phytochrome A gene (PHYA) and its flanking DNA from Arabidopsis thaliana and have identified transcription start sites for three nested transcripts of increasing length. The overall structure of the gene is similar as regards exon/intron organization to other angiosperm PHY genes characterized. The triple transcription start site arrangement is similar to that of pea PHYA but different from the single start site of oat, rice and maize PHYA genes, indicating a possible monocot‐dicot difference. Comparison of the Arabidopsis PHYA promoter sequence with others available indicates that both pea and Arabidopsis promoters contain a DNA element with a core sequence motif identical to one conserved in all existing monocot PHYA sequences and denned by functional assay in the oat PHYA gene as repressor element, RE1, responsible for negative light regulation.
KINETIC CHARACTERIZATION OF THE REDOX COMPONENTS IN SOLUBILIZED MEMBRANES FROM PORCINE NEUTROPHILS: REDUCTION WITH DITHIONITE AND PHOTOEXCITED NAD(P)H
Authors: Orii Yutaka , Miki Toshiaki , Kakinuma Katsuko 
Published: January 2008

Abstract— Cytochrome b558 in solubilized membranes prepared from porcine neutrophils was reduced by dithionite with a second‐order rate constant of 2.5 times 106 M‐1 s‐1 at pH 7.4 and 20°C accompanied by spectral changes with peaks at 428 nm and 560 nm and isosbestic points at 420 and 441 nm. When an anaerobic mixture of solubilized membranes and NAD(P)H was exposed to a white light, cytochrome b558 was reduced biphasically but with almost the same spectral profiles as in the dithionite reduction. Thus, participation of redox component(s) of unknown nature in the photochemical reduction was suggested.The NAD(P)‐ radical generated by photoexcitation of NAD(P)H with a 355 nm laser pulse under anaerobic conditions also reduced cytochrome b558 with a high rate constant of 4.3 times 108M‐1 s‐1 at pH 7.4 and 20°C. The reduction of cytochrome b558 accompanied a simultaneous reduction of a component having an absorption band around 420 nm, suggesting participation of an iron‐sulfur (Fe‐S) cluster. The cytochrome b558 reduction was followed by its reoxidation by another component with an apparent second‐order rate constant of 6.5 times 105M‐1 s‐1. During the reoxidation, the Fe‐S‐like component remained in the reduced state, and thus its role other than as electron mediator in neutrophils NADPH oxidase is suggested. Not only the rate constant but also the extent of cytochrome b558 reoxidation decreased as the same reaction mixture was exposed to the laser pulse repeatedly. This result clearly indicates that an electron accumulates in this electron‐accepting component designated tentatively as the ω component.
THE USE OF LIPID HEADGROUP CHARGE TO ENHANCE PHOTOINDUCED ELECTRON TRANSFER IN VESICLES: REACTIONS OF FUNCTIONALIZED PYRENE WITH A TWO COMPONENT VIOLOGEN SYSTEM
Authors: Li L. , Patterson L. K. 
Published: January 2008

Abstract—Kinetics of photoinduced electron transfer from a lipid functionalized pyrene, 1‐(10‐(6(8)‐octadecylpyrenyl)decanoyl)‐2‐hexanoyl‐.sn‐glycero‐3‐phosphorylcholine (OPyPC), to a two component viologen acceptor system have been measured by laser flash photolysis. N, N'‐tetramethylene‐2,2'‐bi‐pyridinium ion (DQ2+) and N, N'‐dipropyl‐4,4'‐bipyridinium sulfonate (PVS), have been utilized as the primary and secondary acceptors. It has been shown that utilization of a lipid with a net negatively charged phosphatidylglycerol headgroup provides a driving force for localizing high concentrations of primary acceptor (DQ2+) in the region of donor. Subsequently, the charged interface can act to maintain long‐term separation between the oxidized pyrene donor (OPyPC+) and the reduced secondary acceptor, PVS‐. When a dioleoyl lipid is used, reaction of (OPyPC+) with the double bond competes significantly with back reaction. However, substitution of diphytylphosphatidylglycerol for the dioleoyl analog results in a cation lifetime of about 0.5 ms and a continued very long‐lived reduced species (˜4 h). Quantum yields of ˜0.15 may be obtained in this system.
Indications for the Occurrence of Nitric Oxide Synthases in Fungi and Plants and the Involvement in Photoconidiation of Neurospora crassa*
Authors: Ninnemann Helga , Maier Josef 
Published: January 2008

AbstractIndications for the occurrence of nitric oxide synthases in Dictyostelium, Neurospora, Phycomyces and the leguminous plant Mucuna hassjoo as well as a physiological role of nitric oxide in Neurospora crassa are demonstrated. An exogenous nitric oxide donor, sodium nitroprus‐side, inhibited light‐stimulated conidiation in N. crassa. Specific inhibitors of nitric oxide synthase, like the arginine derivatives NG‐nitro‐L‐arginine (L‐NA) and NG‐nitro‐L‐arginine‐methyl ester (L‐NAME), enhanced conidiation in darkness and in the light, whereas the stereo‐isomer D‐NAME was inactive. This communication reports to our knowledge the first time the presence of enzymatic activity of nitric oxide synthase in fungi and a higher plant and an effect of nitric oxide in fungal photophysiology.
Cytolytic Response to HIV in Patients with HIV Disease Treated with Extracorporeal Photochemotherapy: Preliminary Study
Authors: Gonzalez Joselyn , Berger Carole , Cottrill Carolyn M. , Geller Alex , Schwartz Joseph , Palangio Mark , Klainer Albert S. , Bisaccia Emil 
Published: January 2008

ABSTRACTExtracorporeal photochemotherapy (photopheresis), an immunomodulatory therapy that targets circulating T helper lymphocytes, has been applied to the management of human immunodeficiency virus (HIV) disease. Any therapy that exerts its actions on CD4+ T cells has the potential of exacerbating HIV infection. Therefore, it was necessary to observe immune function during treatment. Because cytotoxic T lymphocytes (CTL) and natural killer cells are thought to play an important role in the response against HIV infection, we examined the effect of photopheresis on HIV cytolytic activity. The study group consisted of seven patients with late‐stage HIV disease who had not received any previous treatment for HIV infection. Patients were treated exclusively with photopheresis on two consecutive days each month for 14–32 months (average, 25 months). Peripheral lymphocytes, collected at various points during treatment, were used as effectors in a Wr release assay. Epstein‐Barr virus (EBV)‐transformed autologous B cell lines transfected with recombinant vaccinia vectors that expressed the HIV env (gp120, gp41) and gag (p24) proteins were used as target cells. All seven patients demonstrated relatively constant levels of cytolysis (>10% above controls) during treatment in the context of stable CD4+ T cell counts and a stable clinical status. These results suggest that extracorporeal photochemotherapy did not impair the cytolytic response to HIV infection and may have enhanced it in some patients.
Aggregation of Chlorophyll a′ in Aqueous Methanol
Authors: Oba Toru , Watanabe Tadashi , Mimuro Mamoru , Kobayashi Masami , Yoshida Shoichiro 
Published: January 2008

ABSTRACTAn aggregate of chlorophyll a′ (Chi a′, C132‐epimer of ChI a) formed in a methanovwater (40160, vol/vol) mixed solvent was examined by visible absorption, circular dichro‐ism (CD), fluorescence and resonance Raman spectrosco‐pies in relation to its possible involvement in the core of photosystem I reaction center. The Chl a′ aggregate exhibited a sharp, double‐peaked absorption spectrum (690 and 715 nm) accompanied by an intense, conservative CD signal. The fluorescence excitation polarization spectrum showed that the doublet results from the exciton splitting in a single aggregate species. Time‐dependent changes in the spectroscopic properties clearly point to a simple transformation process from one molecular species to another, though a minor component appears to coexist. This conclusion was supported also by the principal multicom‐ponent spectral estimation analysis of the transients of absorption spectra. The species formed at the initial stage is most probably a T‐shaped dimer or oligomer, which is then gradually converted into the final major product, presumably a stacked dimer. In both of these states, the Chl molecules are linked together via direct coordination of the C13’keto carbonyl oxygen onto the Mg atom of neighboring molecules, as suggested by almost identical resonance Raman spectra in ordinary and deuterated methanovwater mixed solvents. The stacked dimers probably further associate to form a colloidal state in this solvent system. Based on these results, a model for the Chl a′ aggregation is proposed.
Voyage au Bout de la Nuit: The Beginning (1870–1951)*
Authors: Latarjet Raymond 
Published: January 2008

ABSTRACTThis is a history of photobiology from its beginning in 1870 until 1951. In 1928, the Comité International de la Lumiére (C.I.L.) was founded. Up to this point, almost all of the research and activity occurred on the continent of Western Europe, and the research was largely medical. Thereafter, the area of organized photobiology broadened and, in 1951, the name was changed to Comité International de Photobiologie (C.I.P.).
Separate Sensory Pathways for Photomorphogenesis in Phycomyces
Authors: Flores Rafael , Cerdá‐Olmedo Enrique , Corrochano Luis M. 
Published: January 2008

ABSTRACTThe zygomycete Phycomyces blakesleeanus develops two types of sporangiophores of very different size: macrophores and microphores. Blue light inhibits the development of microphores and stimulates the development of macrophores. These responses are called photomicrophorogenesis and photomacrophorogenesis, respectively; phototropism designates the growth of the macrophores toward blue light and photocarotenogenesis, the increased accumulation of β‐carotene under blue light. We have isolated three pim mutants that develop microphores under continuous illumination at fluence rates that inhibit them in the wild type. The thresholds for photomicrophorogenesis in the mutants were higher than in the wild type, but the thresholds for photomacrophorogenesis and phototropism did not change. At least one of the pim mutants had a much higher threshold for photocarotenogenesis than the wild type. A madJ mutant strain, already known for its very defective phototropism, was defective for photomicrophorogenesis, but normal for photomacrophorogenesis and photocarotenogenesis. The requirement for the pim and madJ gene functions separates the two photomorphogenetic responses. The results indicate that the four responses to blue light are based on a combinatorial use of sensory transducers.
Risk of Gastrointestinal Disease Associated with Exposure to Pathogens in the Water of the Lower Passaic River
Authors: Donovan Ellen , Unice Ken , Roberts Jennifer D. , Harris Mark , Finley Brent 
Published: December 2007

ABSTRACT

During precipitation events, untreated human sewage is often intentionally discharged to surface water bodies via combined sewer overflow (CSO) systems in order to avoid overloading wastewater treatment plants. The purpose of this analysis was to evaluate the risk of pathogen-related disease associated with CSO discharges into the Lower Passaic River. Concentrations of fecal coliform, total coliform, fecal
Streptococcus
, and fecal
Enterococcus
bacteria were measured at six river locations on six different days in 2003 (
n
= 36). In addition, water samples (
n
= 2) were collected directly from and in the immediate vicinity of a discharging CSO in Newark, NJ. These samples were analyzed for fecal coliforms, total coliforms, fecal
Streptococcus
, fecal
Enterococcus
,
Giardia lamblia
,
Cryptosporidium parvum
, and several viruses. Risk estimates for gastrointestinal illness and
Giardia
infection resulting from indirect and direct ingestion of contaminated water were calculated for three potential exposure scenarios: visitor, recreator, and homeless person. Single-event risk was first evaluated for the three individual exposure scenarios; overall risk was then determined over a 1-year period. Monte Carlo techniques were used to characterize uncertainty. Nearly all of the pathogen concentrations measured in the Passaic River exceeded health-based water quality criteria and in some cases were similar to levels reported for raw sewage. The probability of contracting gastrointestinal illness due to fecal
Streptococcus
and
Enterococcus
from incidental ingestion of water over the course of a year ranged from 0.14 to nearly 0.70 for the visitor and recreator scenarios, respectively. For the homeless person exposure scenario, the risk for gastrointestinal illness reached 0.88 for fecal
Streptococcus
and
Enterococcus
, while the probability of
Giardia
infection was 1.0. This risk analysis suggests that, due to the levels of pathogens present in the Lower Passaic River, contact with the water poses, and will continue to pose, significant human health risks until CSO discharges are adequately controlled or abated.
Blackbirds and Song Thrushes Constitute a Key Reservoir of
Borrelia garinii
, the Causative Agent of Borreliosis in Central Europe
Authors: Taragel'ová Veronika , Koči Juraj , Hanincová Klára , Kurtenbach Klaus , Derdáková Markéta , Ogden Nick H. , Literák Ivan , Kocianová Elena , Labuda Milan 
Published: December 2007

ABSTRACT

Blackbirds (
Turdus merula
) and song thrushes (
Turdus philomelos
) were found to carry 95% of all spirochete-infected tick larvae among 40 bird species captured in Central Europe. More than 90% of the infections were typed as
Borrelia garinii
and
Borrelia valaisiana
. We conclude that thrushes are key players in the maintenance of these spirochete species in this region of Central Europe.
Contribution of Citrate Metabolism to the Growth of
Lactococcus lactis
CRL264 at Low pH
Authors: Sánchez Claudia , Neves Ana Rute , Cavalheiro João , dos Santos Margarida Moreira , García-Quintáns Nieves , López Paloma , Santos Helena 
Published: December 2007

ABSTRACT

Lactococcus lactis
subsp.
lactis
biovar diacetylactis CRL264 is a natural strain isolated from cheese (F. Sesma, D. Gardiol, A. P. de Ruiz Holgado, and D. de Mendoza, Appl. Environ. Microbiol. 56:2099-2103, 1990). The effect of citrate on the growth parameters at a very acidic pH value was studied with this strain and with derivatives whose citrate uptake capacity was genetically manipulated. The culture pH was maintained at 4.5 to prevent alkalinization of the medium, a well-known effect of citrate metabolism. In the presence of citrate, the maximum specific growth rate and the specific glucose consumption rate were stimulated. Moreover, a more efficient energy metabolism was revealed by analysis of the biomass yields relative to glucose consumption or ATP production. Thus, it was shown that the beneficial effect of citrate on growth under acid stress conditions is not primarily due to the concomitant alkalinization of the medium but stems from less expenditure of ATP, derived from glucose catabolism, to achieve pH homeostasis. After citrate depletion, a deleterious effect on the final biomass was apparent due to organic acid accumulation, particularly acetic acid. On the other hand, citrate metabolism endowed cells with extra ability to counteract lactic and acetic acid toxicity. In vivo
13
C nuclear magnetic resonance provided strong evidence for the operation of a citrate/lactate exchanger. Interestingly, the greater capacity for citrate transport correlated positively with the final biomass and growth rates of the citrate-utilizing strains. We propose that increasing the citrate transport capacity of CRL264 could be a useful strategy to improve further the ability of this strain to cope with strongly acidic conditions.
Risk of Gastrointestinal Disease Associated with Exposure to Pathogens in the Sediments of the Lower Passaic River
Authors: Donovan E. P. , Staskal D. F. , Unice K. M. , Roberts J. D. , Haws L. C. , Finley B. L. , Harris M. A. 
Published: December 2007

ABSTRACT

High levels of pathogenic microorganisms have been documented previously in waters of the Lower Passaic River in northern New Jersey. The purpose of this study was to characterize the microbial contamination of river sediments near combined sewer overflows (CSOs), a known source of pathogens. Concentrations of fecal coliform, total coliform, fecal
Streptococcus
, fecal
Enterococcus
,
Pseudomonas aeruginosa
,
Staphylococcus aureus
,
Giardia lamblia
, and
Cryptosporidium parvum
organisms were measured in 16 samples from three mudflat locations along the Lower Passaic River, as well as from an upstream location. Selected samples were also analyzed for antibiotic resistance. All of the samples contained high concentrations of total coliform, fecal coliform, fecal
Streptococcus
, and fecal
Enterococcus
organisms. Analysis of isolates of
Staphylococcus aureus
,
Pseudomonas aeruginosa
, and
Escherichia coli
from several samples indicated that each strain was resistant to at least one antibiotic typically used in clinical settings. Eight of 16 samples contained
Giardia
, and one sample contained
Cryptosporidium
. With these sampling data, a quantitative microbial risk assessment was conducted to evaluate the probability of infection or illness resulting from incidental ingestion of contaminated sediments over a 1-year period. Three potential exposure scenarios were considered: visitor, recreator, and homeless person. Single-event risk was first evaluated for the three individual exposure scenarios; overall risk was then determined over a 1-year period using Monte Carlo techniques to characterize uncertainty. For fecal
Streptococcus
and
Enterococcus
, annualized risk estimates for gastrointestinal illness ranged from approximately 0.42 to 0.53 for recreators, 0.07 to 0.10 for visitors, and 0.62 to 0.72 for homeless individuals across the three sampling locations. Annualized risk of
Giardia
infection ranged from 0.14 to 0.64 for recreators, 0.01 to 0.1 for visitors, and 0.30 to 0.87 for homeless individuals, across all locations where detected.
Cryptosporidium
was detected at one location, and the corresponding annualized risk of infection was 0.32, 0.05, and 0.51 for recreators, visitors, and homeless individuals, respectively. This risk assessment suggests that pathogen-contaminated sediments near areas of CSO discharge in the Lower Passaic River could pose a health risk to individuals coming into contact with sediments in the mudflat areas.
Enrichment, Isolation, and Phylogenetic Identification of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria from Elizabeth River Sediments
Authors: Hilyard Edward J. , Jones-Meehan Joanne M. , Spargo Barry J. , Hill Russell T. 
Published: December 2007

ABSTRACT

The diversity of indigenous bacteria in sediments from several sites in the Elizabeth River (Virginia) able to degrade multiple polycyclic aromatic hydrocarbons (PAHs) was investigated by the use of classical selective enrichment and molecular analyses. Enrichment cultures containing naphthalene, phenanthrene, fluoranthene, or pyrene as a sole carbon and energy source were monitored by denaturing gradient gel electrophoresis (DGGE) to detect changes in the bacterial-community profile during enrichment and to determine whether the representative strains present were successfully cultured. The DGGE profiles of the final enrichments grown solely on naphthalene and pyrene showed no clear relationship with the site from which the inoculum was obtained. The enrichments grown solely on pyrene for two sample sites had >80% similarity, which suggests that common pyrene-degrading strains may be present in these sediments. The final enrichments grown on fluoranthene and phenanthrene remained diverse by site, suggesting that these strains may be influenced by environmental conditions. One hundred and one isolates were obtained, comprising representatives of the actinomycetes and alpha-, beta-, and gammaproteobacteria, including seven novel isolates with 16S rRNA gene sequences less than 98% similar to known strains. The ability to degrade multiple PAHs was demonstrated by mineralization of
14
C-labeled substrate and growth in pure culture. This supports our hypothesis that a high diversity of bacterial strains with the ability to degrade multiple PAHs can be confirmed by the combined use of classical selective enrichment and molecular analyses. This large collection of diverse PAH-degrading strains provides a valuable resource for studies on mechanisms of PAH degradation and bioremediation.