bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antioxidative Responses of Two Marine Microalgae During Acclimation to Static and Fluctuating Natural UV Radiation
Authors: Janknegt Paul J. , De Graaff C. Marco , Van De Poll Willem H. , Visser Ronald J. W. , Helbling E. Walter , Buma Anita G. J. 
Published: August 2009

AbstractPhotoacclimation properties were investigated in two marine microalgae exposed to four ambient irradiance conditions: static photosynthetically active radiation (PAR: 400–700 nm), static PAR + UVR (280–700 nm), dynamic PAR and dynamic PAR + UVR. High light acclimated cultures of Thalassiosira weissflogii and Dunaliella tertiolecta were exposed outdoors for a maximum of 7 days. Dynamic irradiance was established by computer controlled vertical movement of 2 L bottles in a water filled basin. Immediate (<24 h), short‐term (1–3 days) and long‐term (4–7 days) photoacclimation was followed for antioxidants (superoxide dismutase, ascorbate peroxidase and glutathione cycling), growth and pigment pools. Changes in UVR sensitivity during photoacclimation were monitored by measuring UVR‐induced inhibition of carbon assimilation under standardized UV conditions using an indoor solar simulator. Both species showed immediate antioxidant responses due to their transfer to the outdoor conditions. Furthermore, upon outdoor exposure, carbon assimilation and growth rates were reduced in both species compared with initial conditions; however, these effects were most pronounced in D. tertiolecta. Outdoor UV exposure did not alter antioxidant levels when compared with PAR‐only controls in both species. In contrast, growth was significantly affected in the static UVR cultures, concurrent with significantly enhanced UVR resistance. We conclude that antioxidants play a minor role in the reinforcement of natural UVR resistance in T. weissflogii and D. tertiolecta.
Erythemal Ultraviolet Exposure in Two Groups of Outdoor Workers in Valencia, Spain
Authors: Serrano María Antonia , Cañada Javier , Moreno Juan Carlos ,   of the Solar Radiation Group
Published: August 2009

AbstractUVexposure is considered to be one of the most important risk factors in skin cancers, mainly in outdoor occupational activities. Outdoor workers receive regular and significant solar UV erythemal radiation (UVER). To quantify the UVER exposure of certain groups of workers, dosimeters are used to measure the biologically effective UV radiation received in the course of their daily work. Two groups of outdoor workers, composed of gardeners and lifeguards, were measured for UVER exposure using sensitive spore‐film filter‐type personal dosimeters (Viospor). The study took place in Valencia, Spain, in June and July 2008, and involved one group of four gardeners and another of five beach lifeguards for a period of 4 and 6 days, respectively. The gardeners’ mean UV exposure was 4.13 ± 0.60 SED day−1, where 1 SED is defined as effective 100 J m−2 when weighted with the CIE erythemal response function, whereas the lifeguards received 11.43 ± 2.15 SED day−1. The mean exposure ratio (ER) relative to ambient of gardeners was 0.09 ± 0.01 and for lifeguards was 0.27 ± 0.05. ER is defined as the ratio between the personal dose on a selected anatomical site and the corresponding ambient dose on a horizontal plane during the same exposure period. The lifeguards received the highest UVER exposure, although both groups had measured UVER exposure in excess of occupational guidelines, indicating that protective measures are necessary.
Exploitation of Immune Response‐eliciting Properties of Hypocrellin Photosensitizer SL052‐based Photodynamic Therapy for Eradication of Malignant Tumors
Authors: Korbelik Mladen , Merchant Soroush , Huang Naiyan 
Published: August 2009

AbstractA diaminophenyl derivative of hypocrellin B (SL052) has been developed as a photosensitizer for use in photodynamic therapy (PDT) of solid tumors. Testing SL052‐PDT on mouse carcinoma and fibrosarcoma models revealed a typical response seen with clinically established photosensitizers featuring initial rapid tumor ablation with ensuing recurrence at rates dependent on photosensitizer/light doses. Elevated numbers of immune cells were found in lymph nodes draining SCCVII mouse squamous cell carcinomas treated by SL052‐PDT (in particular T cells), and the accumulation of degranulating cytotoxic T cells was detected at the tumor‐treated site. This indicates that a significant contribution to tumor cures is elicited by an antitumor adaptive immune response. Two different immunotherapy agents, γ‐interferon and antibody blocking inhibitory FcγRIIB receptor, were both found to be highly effective in potentiating the curative effect of SL052‐PDT with SCCVII tumors. Combining SL052‐PDT with FcγRIIB‐blocking antibody treatment caused a further increase in the number of cells in tumor‐draining lymph nodes and in degranulating CD8+ cells, suggesting the amplification of the immune response induced by PDT. Vaccines consisting of SCCVII cells treated with SL052‐PDT in vitro were effective in reducing growth of established subcutaneous SCCVII tumors. In conclusion, PDT mediated by SL052 is suitable to be integrated with various immunotherapy protocols.
Vitamin D Level in Summer and Winter Related to Measured UVR Exposure and Behavior
Authors: Thieden Elisabeth , Philipsen Peter A. , Heydenreich Jakob , Wulf Hans Christian 
Published: August 2009

AbstractThe influence of the summer UVR exposure on serum‐25‐hydroxyvitamin D (25(OH)D) in late summer and winter was investigated in an open study on 25 healthy, adult volunteers. The UVR exposure dose in standard erythema dose (SED) was monitored continuously during a summer season with personal, electronic wristwatch UVR dosimeters and sun exposure diaries. Constitutive and facultative skin pigmentation was measured in September. 25(OH)D was measured in September and February and was in mean 82 nmol/L ± 25 (mean ± SD) in September and 56 nmol/L ± 19 (mean ± SD) in February. The received cumulative UVR dose measured during a mean of 121 days was 156 SED ± 159 (mean ± SD). The following UVR exposure parameters correlated with 25(OH)D in September and February, respectively: (1) The cumulative UVR dose (r = 0.53; P < 0.01) and (r = 0.43; P = 0.03); (2) Mean daily hours with UVR measurements monitored by the dosimeter (r = 0.64, P = 0.001) and (r = 0.53; P = 0.007); (3) Days “with sun‐exposed upper body” (r = 0.58, P = 0.003) and (r = 0.50; P = 0.01); (4) Facultative pigmentation (r = 0.47; P < 0.02) and (r = 0.7; P < 0.001); (5) Constitutive pigmentation (r = 0.06, n.s.) and (r = 0.43, P = 0.03). Neither days “sunbathing” nor days with “sunscreen applied” correlated with 25(OH)D. The fall in 25(OH)D during winter was dependent on the entry value.
Photosensitized Effects of Rose Bengal on Structure and Function of Lens Protein “Alpha‐Crystallin”
Authors: Youssef Tareq , Kassem Mohamed , Abdella Tarek , Harith Mohamed A. , Lenci Francesco 
Published: August 2009

AbstractThe conformational changes of the bovine lens protein “α‐crystallin” have been investigated in the presence of the photosensitizer Rose Bengal (RB), in the dark as well as after visible light irradiation. Absorption and fluorescence emission spectra of RB [5 × 10−6 m] and Fourier transform‐IR spectra of α‐crystallin [5 mg mL−1] were significantly altered upon RB α‐crystallin complex formation. RB was found to bind to α‐crystallin in a molecular pocket characterized by a low polarity, with Trp most likely involved in this interaction. The binding constant (Kb) has been estimated to be of the order of 2.5 (mg/mL)−1. The intrinsic fluorescence of α‐crystallin was quenched through both dynamic and static mechanisms. Light‐induced photosensitized effects showed structural modifications in α‐crystallin, including tertiary and secondary structure (an increase in unordered structure) alterations. Notwithstanding those photoinduced structural variations detected in α‐crystallin when complexed with RB, the protein still retains its ability to play the role of chaperone for β‐crystallin.
Photoproducts Formed in the Photoyellowing of Collagen in the Presence of a Fluorescent Whitening Agent
Authors: Dyer Jolon M. , Clerens Stefan , Cornellison Charisa D. , Murphy Chris J. , Maurdev George , Millington Keith R. 
Published: August 2009

AbstractFibrous proteins discolor on exposure to the UV component of sunlight. This effect is exacerbated in the presence of fluorescent whitening agents (FWAs), which are often applied to textiles to improve product brightness. Tryptophan photoproducts have been identified as significant contributors to protein photoyellowing; however, the role of non–tryptophan‐derived chromophores is less clear. In this study bovine collagen, containing no tryptophan residues, was irradiated in the presence and absence of the stilbene‐derived FWA, 4,4′‐bis(2‐sulfostyryl)biphenyl (DSBP) and photoproducts were identified using mass spectrometry. Photoyellowing was found to be dependent on the presence of the FWA, attributed to amplified generation of reactive oxygen species (ROS), particularly hydroxyl radicals and peroxynitrite. Four key proteinaceous photomodifications contributing directly to photoyellowing were located in irradiated collagen pretreated with DSBP, namely dopa, nitrophenylalanine, nitrotyrosine and nitrohistidine. This represents the first direct characterization of the three nitrated residues in the photoyellowing of an isolated fibrous protein, and implicates the ROS, peroxynitrite, as a key contributor to protein photoyellowing. Direct oxidative modification of the FWA itself was also observed. This study demonstrates that, even in the absence of tryptophan residues, significant photomodification of protein residues leading to chromophore formation occurs in the presence of an FWA.
Sideroblastic changes of the bone marrow can be predicted by the erythrogram of peripheral blood
Authors: ROVÓ A. , STÜSSI G. , MEYER‐MONARD S. , FAVRE G. , TSAKIRIS D. , HEIM D. , HALTER J. , ARBER C. , PASSWEG J. , GRATWOHL A. , TICHELLI A. 
Published: August 2009

SummaryThe diagnosis of sideroblastic anemia is based on bone marrow aspiration, and the detection of ring sideroblasts (RS) in iron staining. The finding of laboratory parameters to approach this diagnosis still remains a great challenge. In this study, we analyzed the value of a specific erythrogram pattern from peripheral blood, produced by the ADVIA®120 cell counter, to predict sideroblastic changes in the bone marrow. In a two step‐design study, we first showed that 32/38 consecutive patients reporting ≥15% RS had such a pattern in the erythrogram. In the second step, we prospectively identified over a period of 32 months 21 patients with this typical erythrogram; 20/21 had ≥15% RS in the bone marrow. Hence, by this validation, we confirm that the erythrogram is highly predictive of RS in the bone marrow. The interpretation of the erythrogram should become daily practice in hematology to improve the efficacy to detect sideroblastic changes.
Effects of 4‐Aminopyridine on Cloned hERG Channels Expressed in Mammalian Cells
Authors: Renganathan Muthukrishnan , Sidach Serguei , Blight Andrew R. 
Published: August 2009

ABSTRACTIntroduction.  Non‐clinical evaluation of a medication's potential to induce cardiac toxicity is recommended by regulatory agencies. 4‐Aminopyridine (fampridine) is a potassium channel blocker with the demonstrated ability to improve walking ability in patients with multiple sclerosis. We evaluated the in vitro effects of 4‐aminopyridine on the human ether‐à‐go‐go‐related gene (hERG) channel current, since hERG current inhibition is associated with QT interval prolongation—a precursor to torsade de pointes (TdP).Methods.  4‐Aminopyridine was evaluated in concentrations ranging from 0.1 mM to 30 mM in human embryonic kidney 293 cells stably transfected with the hERG gene; terfenadine 60 nM was used as a positive control.Results and Discussion.  We observed concentration‐dependent inhibition of hERG current with 4‐aminopyridine doses between 0.3 and 30 mM. The concentration of 3.8 mM resulting in 50% inhibition (IC50) is approximately three orders of magnitude higher than expected therapeutic plasma concentrations, suggesting 4‐aminopyridine has low potential for prolonging QT interval or inducing TdP.
Biogenic Formation of As-S Nanotubes by Diverse
Shewanella
Strains
Authors: Jiang Shenghua , Lee Ji-Hoon , Kim Min-Gyu , Myung Nosang V. , Fredrickson James K. , Sadowsky Michael J. , Hur Hor-Gil 
Published: August 2009

ABSTRACT

Shewanella
sp. strain HN-41 was previously shown to produce novel, photoactive, As-S nanotubes via the reduction of As(V) and S
2
O
3
2−
under anaerobic conditions. To determine if this ability was unique to this bacterium, 10 different
Shewanella
strains, including
Shewanella
sp. strain HN-41,
Shewanella
sp. strain PV-4,
Shewanella alga
BrY,
Shewanella amazonensis
SB2B,
Shewanella denitrificans
OS217,
Shewanella oneidensis
MR-1,
Shewanella putrefaciens
CN-32,
S. putrefaciens
IR-1,
S. putrefaciens
SP200, and
S. putrefaciens
W3-6-1, were examined for production of As-S nanotubes under standardized conditions. Of the 10 strains examined, three formed As-S nanotubes like those of strain HN-41. While
Shewanella
sp. strain HN-41 and
S. putrefaciens
CN-32 rapidly formed As-S precipitates in 7 days, strains
S. alga
BrY and
S. oneidensis
MR-1 reduced As(V) at a much lower rate and formed yellow As-S after 30 days. Electron microscopy, energy-dispersive X-ray spectroscopy, and extended X-ray absorption fine-structure spectroscopy analyses showed that the morphological and chemical properties of As-S formed by strains
S. putrefaciens
CN-32,
S. alga
BrY, and
S. oneidensis
MR-1 were similar to those previously determined for
Shewanella
sp. strain HN-41 As-S nanotubes. These studies indicated that the formation of As-S nanotubes is widespread among
Shewanella
strains and is closely related to bacterial growth and the reduction rate of As(V) and thiosulfate.
Pseudoalteromonas
Bacteria Are Capable of Degrading Paralytic Shellfish Toxins
Authors: Donovan Carrie J. , Garduño Rafael A. , Kalmokoff Martin , Ku John C. , Quilliam Michael A. , Gill Tom A. 
Published: August 2009

ABSTRACT

Marine bacterial isolates cultured from the digestive tracts of blue mussels (
Mytilus edulis
) contaminated with paralytic shellfish toxins (PSTs) were screened for the ability to reduce the toxicity of a PST mixture. Seven isolates reduced the overall toxicity of the algal extract by ≥90% within 3 days. These isolates shared at least 99% 16S rRNA gene sequence similarity with five
Pseudoalteromonas
spp. Phenotypic tests suggested that all are novel strains of
Pseudoalteromonas haloplanktis
.
Assessment of the Microbial Ecology of Ruminal Methanogens in Cattle with Different Feed Efficiencies
Authors: Zhou Mi , Hernandez-Sanabria Emma , Guan Le Luo 
Published: August 2009

ABSTRACT

Cattle with high feed efficiencies (designated “efficient”) produce less methane gas than those with low feed efficiencies (designated “inefficient”); however, the role of the methane producers in such difference is unknown. This study investigated whether the structures and populations of methanogens in the rumen were associated with differences in cattle feed efficiencies by using culture-independent methods. Two 16S rRNA libraries were constructed using ∼800-bp amplicons generated from pooled total DNA isolated from efficient (
n
= 29) and inefficient (
n
= 29) animals. Sequence analysis of up to 490 randomly selected clones from each library showed that the methanogenic composition was variable: less species variation (22 operational taxonomic units [OTUs]) was detected in the rumens of efficient animals, compared to 27 OTUs in inefficient animals. The methanogenic communities in inefficient animals were more diverse than those in efficient ones, as revealed by the diversity indices of 0.84 and 0.42, respectively. Differences at the strain and genotype levels were also observed and found to be associated with feed efficiency in the host. No difference was detected in the total population of methanogens, but the prevalences of
Methanosphaera stadtmanae
and
Methanobrevibacter
sp. strain AbM4 were 1.92 (
P
< 0.05) and 2.26 (
P
< 0.05) times higher in inefficient animals, while
Methanobrevibacter
sp. strain AbM4 was reported for the first time to occur in the bovine rumen. Our data indicate that the methanogenic ecology at the species, strain, and/or genotype level in the rumen may play important roles in contributing to the difference in methane gas production between cattle with different feed efficiencies.
Complex Nature of the Genome in a Wine Spoilage Yeast,
Dekkera bruxellensis
Authors: Hellborg Linda , Piškur Jure 
Published: August 2009

ABSTRACT

When the genome organizations of 30 native isolates belonging to a wine spoilage yeast,
Dekkera
(
Brettanomyces
)
bruxellensis
, a distant relative of
Saccharomyces cerevisiae
, were examined, the numbers of chromosomes varied drastically, from 4 to at least 9. When single gene probes were used in Southern analysis, the corresponding genes usually mapped to at least two chromosomal bands, excluding a simple haploid organization of the genome. When different loci were sequenced, in most cases, several different haplotypes were obtained for each single isolate, and they belonged to two subtypes. Phylogenetic reconstruction using haplotypes revealed that the sequences from different isolates belonging to one subtype were more similar to each other than to the sequences belonging to the other subtype within the isolate. Reanalysis of the genome sequence also confirmed that partially sequenced strain Y879 is not a simple haploid and that its genome contains approximately 1% polymorphic sites. The present situation could be explained by (i) a hybridization event where two similar but different genomes have recently fused together or (ii) an event where the diploid progenitor of all analyzed strains lost a regular sexual cycle, and the genome started to accumulate mutations.
Trypanosome Prereplication Machinery Contains a Single Functional Orc1/Cdc6 Protein, Which Is Typical of
Archaea
Authors: Godoy Patrícia Diogo de Melo , Nogueira-Junior Luis Antonio , Paes Lisvane S. , Cornejo Alberto , Martins Rafael Miyazawa , Silber Ariel M. , Schenkman Sergio , Elias M. Carolina 
Published: August 2009

ABSTRACT

In unicellular eukaryotes, such as
Saccharomyces cerevisiae
, and in multicellular organisms, the replication origin is recognized by the heterohexamer origin recognition complex (ORC) containing six proteins, Orc1 to Orc6, while in members of the domain
Archaea
, the replication origin is recognized by just one protein, Orc1/Cdc6; the sequence of Orc1/Cdc6 is highly related to those of Orc1 and Cdc6. Similar to
Archaea
, trypanosomatid genomes contain only one gene encoding a protein named Orc1. Since trypanosome Orc1 is also homologous to Cdc6, in this study we named the Orc1 protein from trypanosomes Orc1/Cdc6. Here we show that the recombinant Orc1/Cdc6 from
Trypanosoma cruzi
(TcOrc1/Cdc6) and from
Trypanosoma brucei
(TbOrc1/Cdc6) present ATPase activity, typical of prereplication machinery components. Also, TcOrc1/Cdc6 and TbOrc1/Cdc6 replaced yeast Cdc6 but not Orc1 in a phenotypic complementation assay. The induction of Orc1/Cdc6 silencing by RNA interference in
T. brucei
resulted in enucleated cells, strongly suggesting the involvement of Orc1/Cdc6 in DNA replication. Orc1/Cdc6 is expressed during the entire cell cycle in the nuclei of trypanosomes, remaining associated with chromatin in all stages of the cell cycle. These results allowed us to conclude that Orc1/Cdc6 is indeed a member of the trypanosome prereplication machinery and point out that trypanosomes carry a prereplication machinery that is less complex than other eukaryotes and closer to archaea.
Transcriptional Regulation of theEscherichia coliGenerraB, Encoding a Protein Inhibitor of RNase E
Authors: Zhou Li , Zhao Meng , Wolf Rachel Z. , Graham David E. , Georgiou George 
Published: August 2009

ABSTRACTTheEscherichia coliRNA degradosome is a protein complex that plays a critical role in the turnover of numerous RNAs. The key component of the degradosome complex is the endoribonuclease RNase E, a multidomain protein composed of an N-terminal catalytic region and a C-terminal region that organizes the other protein components of the degradosome. Previously, the RNase E inhibitors RraA and RraB were identified genetically and shown to bind to the C-terminal region of RNase E, thus affecting both the protein composition of the degradosome and the endonucleolytic activity of RNase E. In the present work, we investigated the transcriptional regulation ofrraB.rraBwas shown to be transcribed constitutively from its own promoter, PrraB. Transposon mutagenesis and screening for increased β-galactosidase activity from a chromosomal PrraB-lacZtranscriptional fusion resulted in the isolation of a transposon insertion inglmS, encoding the essential enzyme glucosamine-6-phosphate synthase that catalyzes the first committed step of the uridine 5′-diphospho-N-acetyl-glucosamine (UDP-GlcNAc) pathway, which provides intermediates for peptidoglycan biogenesis. TheglmS852::Tn5allele resulted in an approximately 50% lower intracellular concentration of UDP-GlcNAc and conferred a fivefold increase in the level ofrraBmRNA. This allele also mediated a twofold increase in β-galactosidase activity from a chromosomal fusion of the 5′ untranslated region of thernegene tolacZ, suggesting that a reduction in cellular concentration of UDP-GlcNAc and the resulting increased expression of RraB might modulate the action of RNase E.
Identification of a Polyprenylphosphomannosyl Synthase Involved in the Synthesis of Mycobacterial Mannosides
Authors: Scherman Hataichanok , Kaur Devinder , Pham Ha , Škovierová Henrieta , Jackson Mary , Brennan Patrick J. 
Published: August 2009

ABSTRACT

We report on the identification of a glycosyltransferase (GT) from
Mycobacterium tuberculosis
H37Rv, Rv3779, of the membranous GT-C superfamily responsible for the direct synthesis of polyprenyl-phospho-mannopyranose and thus indirectly for lipoarabinomannan, lipomannan, and the higher-order phosphatidyl-
myo
-inositol mannosides.