bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Structural and Chemical Properties of Black and Red Human Hair Melanosomes¶
Authors: Liu Yan , Hong Lian , Wakamatsu Kazumasa , Ito Shosuke , Adhyaru Bhavin , Cheng Chi‐Yuan , Bowers Clifford R. , Simon John D. 
Published: July 2010

ABSTRACTMelanosomes in black and red human hair are isolated and characterized by various chemical and physical techniques. Different yields of 4‐amino‐hydroxyphenolanaline by HI hydrolysis (a marker for pheomelanin) and pyrrole‐2,3,5‐tricarboxylic acid by KMnO4/H+ oxidation (a marker for eumelanin) indicate that the melanosomes in black hair are eumelanosomes, whereas those in red hair are mainly pheomelanosomes. Atomic force microscopy reveals that eumelanosomes and pheomelanosomes have ellipsoidal and spherical shapes, respectively. Eumelanosomes maintain structural integrity upon extraction from the keratin matrix, whereas pheomelanosomes tend to fall apart. The black‐hair eumelanosomes have an average of 14.6 ± 0.5% amino acids content, which is attributed to the internal proteins entrapped in the melanosomes granules. The red‐hair melanosomes contain more than 44% of amino acid content even after extensive proteolytic digestion. This high content of amino acids and the poorly reserved integrity of red‐hair melanosomes suggest that some proteins are possibly covalently bonded with the melanin constituents in addition to those that are entrapped inside the melanin species. Soluene solubilization assay indicates the absorbance of melanin per gram of sample, adjusted for the amino acid content, is a factor of 2.9 greater for the black‐hair melanosomes than the red‐hair melanosomes. Metal analysis reveals significant amounts of diverse heavy metal ions bound to the two types of melanosomes. The amount of Cu(II) and Zn(II) are similar but Fe(III) content is four times higher in the red‐hair melanosomes. 13C solid‐state nuclear magnetic resonance spectra and infrared spectra are presented and are shown to be powerful techniques for discerning differences in the amino acid contents, the 5,6‐dihydroxyindole‐2‐carboxylic acid:5,6‐dihydroxyindole ratio, and the degree of cross‐linking in the pigment. Excellent agreement is observed between these spectral results and the chemical degradation data.
Effects of the Binding of α/β‐type Small, Acid‐soluble Spore Proteins on the Photochemistry of DNA in Spores of Bacillus subtilis and In Vitro¶
Authors: Douki Thierry , Setlow Barbara , Setlow Peter 
Published: July 2010

ABSTRACTThe main lesion produced in DNA by UV‐C irradiation of spores of Bacillus subtilis is 5‐thyminyl‐5,6‐dihydrothymine (spore photoproduct [SP]). In contrast, cyclobutane pyrimidine dimers (CPD) and pyrimidine (6–4) pyrimidone photoproducts (6–4PP) are the main photolesions in other cell types. The novel photochemistry of spore DNA is accounted for in part by its reduced hydration, but largely by the saturation of spore DNA with α/β‐type small, acid‐soluble spore proteins (SASP). Using high‐performance liquid chromatography‐mass spectrometry analysis of the photoproducts, we showed that in wild‐type B. subtilis spores (1) UV‐C irradiation generates almost exclusively SP with little if any CPD and 6–4PP; (2) the SP generated is ∼99% of the intrastrand derivative, but ∼1% is in the interstrand form; and (3) there is no detectable formation of the SP analog between adjacent C and T residues. UV‐C irradiation of spores lacking the majority of their α/β‐type SASP gave less SP than with wild‐type spores and significant levels of CPD and 6–4PP. The binding of an α/β‐type SASP to isolated DNA either in dry films or in aqueous solution led to a large decrease in the yield of CPD and 6–4PP, and a concomitant increase in the yield of SP, although levels of interstrand photoproducts were extremely low.
Autophosphorylation, Electrophoretic Mobility and Immunoreaction of Oat Phototropin 1 Under UV and Blue Light¶
Authors: Knieb Elke , Salomon Michael , Rüdiger Wolfhart 
Published: July 2010

ABSTRACTPhototropins are UV‐A/blue light photoreceptors containing two flavin mononucleotide (FMN)–binding domains, light, oxygen and voltage (LOV)1 and LOV2, of which LOV2 is more sensitive toward light and more important for the physiological response compared with LOV1. Some physiological responses are plant phototropism, chloroplast migration and stomatal opening. Oat phototropin 1 together with light‐dependent autophosphorylation shows a reduced electrophoretic mobility and reduced immunoreaction against a heterologous antiserum; both effects were suggested to be caused by phosphorylation at the same sites (M. Salomon, E. Knieb, T. von Zeppelin and W. Rüdiger [2003] Biochemistry42, 4217–4225). In this study, we show that both effects can be separated from each other: at low temperature, reduced immunoreaction preceded the mobility shift, and irradiation with UV‐C light led to the mobility shift without the loss of immunoreactivity. We demonstrated that UV‐C light at 280 nm, which does not match any absorption maximum of FMN, leads to autophosphorylation of phototropin. It is hypothesized that UV‐C light causes differential activation of the LOV domains via energy transfer from aromatic amino acids.
The Separation of Hypericin's Enantiomers and Their Photophysics in Chiral Environments¶
Authors: Sanders Lindsay , Halder Mintu , Xiao Tom Ling , Ding Jie , Armstrong Daniel W. , Petrich Jacob W. 
Published: July 2010

ABSTRACTWe report the first separation of the enantiomers of hypericin. Their steady‐state optical spectra and ultrafast primary photoprocesses are investigated in chiral environments. Within experimental error, there is no difference between the two enantiomers in any of the systems considered. This is consistent with the emerging picture that the rich and extended absorption spectrum of hypericin is not a result of ground‐state heterogeneity. It is also consistent with the observation that the spectra and photophysics of hypericin are generally insensitive to environments in which it does not aggregate.
Vertical Migration and Motility Responses in Three Marine Phytoplankton Species Exposed to Solar Radiation†
Authors: Richter Peter R. , Häder Donat‐P. , Gonçalves Rodrigo J. , Marcoval M. Alejandra , Villafañe Virginia E. , Helbling E. Walter 
Published: July 2010

ABSTRACTDiurnal vertical migration in the water column and the impact of solar radiation on motility were investigated in three marine phytoplankton species: Tetraselmis suecica, Dunaliella salina and Gymnodinium chlorophorum. Cells were exposed to solar radiation either in ultraviolet radiation (UVR, 280–400 nm) transparent Plexiglas tubes (45 cm length, 10 cm diameter) or in quartz tubes under three radiation treatments: PAB (280–700 nm), PA (320–700 nm) and P (400–700 nm). The three species displayed different behavior after exposure to solar radiation. Tetraselmis suecica was insensitive to UVR and under high solar radiation levels, cells accumulated preferentially near the surface. Exposure experiments did not indicate any significant changes in swimming speed nor in the percentage of motile cells after 5 h of exposure. On the other hand, D. salina was sensitive to UV‐B displaying a significant decrease in swimming speed and percentage of motile cells after 2–3 h of exposure. Moreover, D. salina cells migrated deep in the water column when irradiance was high. The response of G. chlorophorum was in between that of the other two species tested, with a slight (but significant) decrease in swimming speed and percentage of motile cells in all radiation treatments after 5 h of exposure. While G. chlorophorum cells were more or less homogenously distributed in the water column, a slight (but significant) avoidance response to high radiation was observed at local noon, with cells migrating deep in the water column. Our data clearly indicate that these sub‐lethal effects of solar radiation are species‐specific and they might have important implications for the aquatic ecosystem.
Photobleaching of Melanosomes from Retinal Pigment Epithelium: I. Effects on Protein Oxidation
Authors: Burke Janice M. , Henry Michele M. , Zareba Mariusz , Sarna Tadeusz 
Published: July 2010

ABSTRACTMelanin in the long‐lived melanosomes of the retinal pigment epithelium (RPE) may undergo photobleaching with aging, which appears to diminish the antioxidant function of melanin and could make photobleached melanosomes less efficient in protecting biomolecules from oxidative modification. Here we analyzed whether photobleaching of melanosomes affects their ability to modify the oxidation state of nearby protein. As conventional methods developed to study soluble antioxidants are not well suited for analysis of granules such as melanosomes, we developed a new analytic method to focus on particle surfaces that involves experimentally coating granules with the cytoskeletal protein β‐actin to serve as a reporter for local protein oxidation. Isolated porcine RPE melanosomes were photobleached with visible light to simulate aging, then photobleached melanosomes, untreated melanosomes and control particles (black latex beads) were actin coated and illuminated in a photosensitized cell free system. Protein was re‐stripped from particles and analyzed for carbonylation by Western blotting. Quantitative densitometry showed no reproducible differences for protein associated with untreated melanosomes when compared with control particles. Melanin has both anti‐ and pro‐oxidant functions when light irradiated, but neither of these functions predominated in the protein oxidation assay when untreated melanosomes were used. However, protein extracted from photobleached melanosomes showed markedly increased carbonylation, both of associated actin and of endogenous melanosomal protein(s), and the effect increased with extent of granule photobleaching. Photobleaching of RPE melanosomes therefore changes the oxidation state of protein endogenous to the organelle and reduces the ability of the granule to modify the oxidation of exogenous protein near the particle surface. The results support the growing body of evidence that photobleaching of RPE melanosomes, which is believed to occur with aging, changes the physicochemical properties of the organelle and reduces the likelihood that the granules perform an antioxidant function.
Bid Is Required in NPe6‐PDT‐induced Apoptosis
Authors: Wan Qingling , Liu Lei , Xing Da , Chen Qun 
Published: July 2010

AbstractPhotodynamic therapy (PDT) employing photosensiter N‐aspartyl chlorin e6 (NPe6) can induce lysosome disruption and initiate the intrinsic apoptotic pathway. Yet the precise signal transduction pathway remains poorly understood. In this study, we have investigated the molecular mechanism in NPe6‐PDT‐induced apoptosis in human lung adenocarcinoma cells (ASTC‐a‐1). A recombinant fluorescence resonance energy transfer (FRET) Bid probe was utilized to determine the kinetics of Bid cleavage. The results show that cleavage of the Bid‐FRET probe occurred 150 ± 5 min after NPe6‐PDT treatment, and this process lasted for 45 ± 5 min. The Bid cleavage coincided with a translocation of tBid from cytoplasm to mitochondria. Remarkably, a significant protection against cell death was observed by using small interfering RNA for Bid. Therefore, our study clearly showed the dynamics of Bid activation and redistribution during NPe6‐PDT‐induced apoptosis by using real‐time analysis in living cells, and the inhibition of cell death by silencing Bid with interference strongly suggested that activation of Bid is required for inducing apoptosis in this experimental model.
Healing Families: An Outcome Evaluation of a Community Family Court
Authors: Rivera Marny 
Published: July 2010

ABSTRACTIn this paper, a model community family court program that seeks to break the intergenerational cycle of crime and substance abuse by treating families holistically will be presented. This model court seeks to reduce crime and provide safe and permanent homes for children of substance‐abusing parents. In this community family court, the prototypical problem‐solving court has been both focused and expanded. The community family court provides a focused response designed to address the unique combination of problems facing families on a family‐by‐family basis. At the same time, supervision and treatment services have been expanded to include every family member and all open court cases including criminal charges, juvenile delinquency, dependency, and civil cases. An overview of the court's evolution and discussion of integrated services designed to provide a wraparound style intervention will be highlighted as key contributors to the largely positive results of this community family court's evaluation.
A Population Genetics-Based and Phylogenetic Approach to Understanding the Evolution of Virulence in the Genus
Listeria
Authors: den Bakker Henk C. , Bundrant Brittany N. , Fortes Esther D. , Orsi Renato H. , Wiedmann Martin 
Published: July 2010

ABSTRACT

The genus
Listeria
includes (i) the opportunistic pathogens
L. monocytogenes
and
L. ivanovii
, (ii) the saprotrophs
L. innocua
,
L. marthii
, and
L. welshimeri
, and (iii)
L. seeligeri
, an apparent saprotroph that nevertheless typically contains the
prfA
virulence gene cluster. A novel 10-loci multilocus sequence typing scheme was developed and used to characterize 67 isolates representing six
Listeria
spp. (excluding
L. grayi
) in order to (i) provide an improved understanding of the phylogeny and evolution of the genus
Listeria
and (ii) use
Listeria
as a model to study the evolution of pathogenicity in opportunistic environmental pathogens. Phylogenetic analyses identified six well-supported
Listeria
species that group into two main subdivisions, with each subdivision containing strains with and without the
prfA
virulence gene cluster. Stochastic character mapping and phylogenetic analysis of
hly
, a gene in the
prfA
cluster, suggest that the common ancestor of the genus
Listeria
contained the
prfA
virulence gene cluster and that this cluster was lost at least five times during the evolution of
Listeria
, yielding multiple distinct saprotrophic clades.
L. welshimeri
, which appears to represent the most ancient clade that arose from an ancestor with a
prfA
cluster deletion, shows a considerably lower average sequence divergence than other
Listeria
species, suggesting a population bottleneck and a putatively different ecology than other saprotrophic
Listeria
species. Overall, our data suggest that, for some pathogens, loss of virulence genes may represent a selective advantage, possibly by facilitating adaptation to a specific ecological niche.
Catabolite Repression of Aox inPichia pastorisIs Dependent on Hexose Transporter PpHxt1 and Pexophagy
Authors: Zhang Ping , Zhang Wenwen , Zhou Xiangshan , Bai Peng , Cregg James M. , Zhang Yuanxing 
Published: July 2010

ABSTRACTIn this work, the identification and characterization of two hexose transporter homologs in the methylotrophic yeastPichia pastoris,P. pastorisHxt1 (PpHxt1) and PpHxt2, are described. When expressed in aSaccharomyces cerevisiae hxt-null mutant strain that is unable to take up monosaccharides, either protein restored growth on glucose or fructose. Both PpHXTgenes are transcriptionally regulated by glucose. Transcript levels of PpHXT1are induced by high levels of glucose, whereas transcript levels of PpHXT2are relatively lower and are fully induced by low levels of glucose. In addition, PpHxt2 plays an important role in glycolysis-dependent fermentative growth, since PpHxt2 is essential for growth on glucose or fructose when respiration is inhibited. Notably, we firstly found that the deletion of PpHXT1, but not PpHXT2, leads to the induced expression of the alcohol oxidase I gene (AOX1) in response to glucose or fructose. We also elucidated that a sharp dropping of the sugar-induced expression level of Aox at a later growth phase is caused mainly by pexophagy, a degradation pathway in methylotrophic yeast. The sugar-inducibleAOX1promoter in an Δhxt1strain may be promising as a host for the expression of heterologous proteins. The functional analysis of these two hexose transporters is the first step in elucidating the mechanisms of sugar metabolism and catabolite repression inP. pastoris.
Novel
In Vivo
-Degradable Cellulose-Chitin Copolymer from Metabolically Engineered
Gluconacetobacter xylinus
Authors: Yadav Vikas , Paniliatis Bruce J. , Shi Hai , Lee Kyongbum , Cebe Peggy , Kaplan David L. 
Published: July 2010

ABSTRACT

Despite excellent biocompatibility and mechanical properties, the poor
in vitro
and
in vivo
degradability of cellulose has limited its biomedical and biomass conversion applications. To address this issue, we report a metabolic engineering-based approach to the rational redesign of cellular metabolites to introduce
N
-acetylglucosamine (GlcNAc) residues into cellulosic biopolymers during
de novo
synthesis from
Gluconacetobacter xylinus
. The cellulose produced from these engineered cells (modified bacterial cellulose [MBC]) was evaluated and compared with cellulose produced from normal cells (bacterial cellulose [BC]). High GlcNAc content and lower crystallinity in MBC compared to BC make this a multifunctional bioengineered polymer susceptible to lysozyme, an enzyme widespread in the human body, and to rapid hydrolysis by cellulase, an enzyme commonly used in biomass conversion. Degradability
in vivo
was demonstrated in subcutaneous implants in mice, where modified cellulose was completely degraded within 20 days. We provide a new route toward the production of a family of tailorable modified cellulosic biopolymers that overcome the longstanding limitation associated with the poor degradability of cellulose for a wide range of potential applications.
Sequencing and Transcriptional Analysis of the
Streptococcus thermophilus
Histamine Biosynthesis Gene Cluster: Factors That Affect Differential
hdcA
Expression
Authors: Calles-Enríquez Marina , Eriksen Benjamin Hjort , Andersen Pia Skov , Rattray Fergal P. , Johansen Annette H. , Fernández María , Ladero Victor , Alvarez Miguel A. 
Published: July 2010

ABSTRACT

Histamine, a toxic compound that is formed by the decarboxylation of histidine through the action of microbial decarboxylases, can accumulate in fermented food products. From a total of 69
Streptococcus thermophilus
strains screened, two strains, CHCC1524 and CHCC6483, showed the capacity to produce histamine. The
hdc
clusters of
S. thermophilus
CHCC1524 and CHCC6483 were sequenced, and the factors that affect histamine biosynthesis and histidine-decarboxylating gene (
hdcA
) expression were studied. The
hdc
cluster began with the
hdcA
gene, was followed by a transporter (
hdcP
), and ended with the
hdcB
gene, which is of unknown function. The three genes were orientated in the same direction. The genetic organization of the
hdc
cluster showed a unique organization among the lactic acid bacterial group and resembled those of
Staphylococcus
and
Clostridium
species, thus indicating possible acquisition through a horizontal transfer mechanism. Transcriptional analysis of the
hdc
cluster revealed the existence of a polycistronic mRNA covering the three genes. The histidine-decarboxylating gene (
hdcA
) of
S. thermophilus
demonstrated maximum expression during the stationary growth phase, with high expression levels correlated with high histamine levels. Limited expression was evident during the lag and exponential growth phases. Low-temperature (4°C) incubation of milk inoculated with a histamine-producing strain showed lower levels of histamine than did inoculated milk kept at 42°C. This reduction was attributed to a reduction in the activity of the HdcA enzyme itself rather than a reduction in gene expression or the presence of a lower cell number.
Identification of the Corn Pathogen
Pantoea stewartii
by Mass Spectrometry of Whole-Cell Extracts and Its Detection with Novel PCR Primers
Authors: Wensing Annette , Zimmermann Stefan , Geider Klaus 
Published: July 2010

ABSTRACT

Pantoea stewartii
subsp.
stewartii
is the causative agent of Stewart's wilt, a bacterial disease transmitted by the corn flea beetle mainly to sweet corn (
Zea mays
). In many countries, it is classified as a quarantine organism and must be differentiated from other yellow enteric bacteria frequently occurring with corn. We have created novel primers from the
pstS-glmS
region of
P. stewartii
for use in conventional PCR (cPCR) and quantitative PCR (qPCR). To facilitate rapid diagnosis, we applied matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis. Using whole-cell protein extracts, profiles were generated with a Bruker microflex machine, and the bacteria classified.
P. stewartii
strains were clearly distinguished from strains of
Pantoea agglomerans
,
Pantoea dispersa
, and
Pantoea ananatis
. Dendrogram analysis of the protein profiles confirmed the score values and showed the formation of separate clades for each species. The identification achieved by MALDI-TOF MS analysis agrees with the diagnosis by specific PCR primers. The combination of both methods allows a rapid and simple identification of the corn pathogen.
P. stewartii
subsp.
stewartii
and
P. stewartii
subsp.
indologenes
are highly related and can be distinguished not only by virulence assays and indole tests but also by a characteristic pattern in the nucleotide sequence of
recA
.
Candida albicans Ume6, a Filament-Specific Transcriptional Regulator, Directs Hyphal Growth via a Pathway Involving Hgc1 Cyclin-Related Protein
Authors: Carlisle Patricia L. , Kadosh David 
Published: July 2010

ABSTRACT

The ability of
Candida albicans
, the most common human fungal pathogen, to transition from yeast to hyphae is essential for pathogenicity. While a variety of transcription factors important for filamentation have been identified and characterized, links between transcriptional regulators of
C. albicans
morphogenesis and molecular mechanisms that drive hyphal growth are not well defined. We have previously observed that constitutive expression of
UME6
, which encodes a filament-specific transcriptional regulator, is sufficient to direct hyphal growth in the absence of filament-inducing conditions. Here we show that
HGC1
, encoding a cyclin-related protein necessary for hyphal growth under filament-inducing conditions, is specifically important for agar invasion, hyphal extension, and formation of true septa in response to constitutive
UME6
expression under non-filament-inducing conditions.
HGC1
-dependent inactivation of Rga2, a Cdc42 GTPase activating protein (GAP), also appears to be important for these processes. In response to filament-inducing conditions,
HGC1
is induced prior to
UME6
although
UME6
controls the level and duration of
HGC1
expression, which are likely to be important for hyphal extension. Interestingly, an epistasis analysis suggests that
UME6
and
HGC1
play distinct roles during early filament formation. These findings establish a link between a key regulator of filamentation and a downstream mechanism important for hyphal formation. In addition, this study demonstrates that a strain expressing constitutive high levels of
UME6
provides a powerful strategy to specifically dissect downstream mechanisms important for hyphal development in the absence of complex filament-inducing conditions.