bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acanthamoeba castellaniiPromotion of In Vitro Survival and Transmission of Coxsackie B3 Viruses
Authors: Mattana A. , Serra C. , Mariotti E. , Delogu G. , Fiori P. L. , Cappuccinelli P. 
Published: April 2006

ABSTRACTThis work was undertaken to determine whetherAcanthamoebacould play a role in the survival and transmission of coxsackieviruses and focused on in vitro interactions betweenAcanthamoeba castellaniiand coxsackie B3 viruses (CVB-3). Residual virus titer evaluations and immunofluorescence experiments revealed a remarkable CVB-3 adsorption on amoeba surfaces and accumulation inside cells. The survival of viruses was independent of the dynamics of amoeba replication and encystment. In addition, our results indicated that virus-infected amoebas can release infectious viruses during interaction with human macrophages. On the basis of these data,Acanthamoebaappears to be a potential promoter of the survival of coxsackieviruses and their transmission to human hosts.
High-Mobility-Group Box Nuclear Factors of
Plasmodium falciparum
Authors: Briquet Sylvie , Boschet Charlotte , Gissot Mathieu , Tissandié Emilie , Sevilla Elisa , Franetich Jean-François , Thiery Isabelle , Hamid Zuhal , Bourgouin Catherine , Vaquero Catherine 
Published: April 2006

ABSTRACT

In eukaryotes, the high-mobility-group (HMG) nuclear factors are highly conserved throughout evolution and are divided into three families, including HGMB, characterized by an HMG box domain. Some HMGB factors are DNA structure specific and preferentially interact with distorted DNA sequences, trigger DNA bending, and hence facilitate the binding of nucleoprotein complexes that in turn activate or repress transcription. In
Plasmodium falciparum
, two HMGB factors were predicted: PfHMGB1 and PfHMGB2. They are small proteins, under 100 amino acids long, encompassing a characteristic HMG box domain closely related to box B of metazoan factors, which comprises two HMG box domains, A and B, in tandem. Computational analyses supported the conclusion that the
Plasmodium
proteins were genuine architectural HMGB factors, and in vitro analyses performed with both recombinant proteins established that they were able to interact with distorted DNA structures and bend linear DNA with different affinities. These proteins were detected in both asexual- and gametocyte-stage cells in Western blotting experiments and mainly in the parasite nuclei. PfHMGB1 is preferentially expressed in asexual erythrocytic stages and PfHMGB2 in gametocytes, in good correlation with transcript levels of expression. Finally, immunofluorescence studies revealed differential subcellular localizations: both factors were observed in the nucleus of asexual- and sexual-stage cells, and PfHMGB2 was also detected in the cytoplasm of gametocytes. In conclusion, in light of differences in their levels of expression, subcellular localizations, and capacities for binding and bending DNA, these factors are likely to play nonredundant roles in transcriptional regulation of
Plasmodium
development in erythrocytes.
Ras GTPase-Activating Protein Gap1 of the Homobasidiomycete
Schizophyllum commune
Regulates Hyphal Growth Orientation and Sexual Development
Authors: Schubert Daniela , Raudaskoski Marjatta , Knabe Nicole , Kothe Erika 
Published: April 2006

ABSTRACT

The white rot fungus
Schizophyllum commune
is used for the analysis of mating and sexual development in homobasidiomycete fungi. In this study, we isolated the gene
gap1
encoding a GTPase-activating protein for Ras. Disruption of
gap1
should therefore lead to strains accumulating Ras in its activated, GTP-bound state and to constitutive Ras signaling. Haploid
Δgap1
monokaryons of different mating types did not show alterations in mating behavior in the four different mating interactions possible in fungi expressing a tetrapolar mating type system. Instead, the growth rate in
Δgap1
monokaryons was reduced by ca. 25% and ca. 50% in homozygous
Δgap1
/
Δgap1
dikaryons. Monokaryons, as well as homozygous dikaryons, carrying the disrupted
gap1
alleles exhibited a disorientated growth pattern. Dikaryons showed a strong phenotype during clamp formation since hook cells failed to fuse with the peg beside them. Instead, the dikaryotic character of the hyphae was rescued by fusion of the hooks with nearby developing branches.
Δgap1
/
Δgap1
dikaryons formed increased numbers of fruitbody primordia, whereas the amount of fruitbodies was not raised. Mature fruitbodies formed no or abnormal gills. No production of spores could be observed. The results suggest Ras involvement in growth, clamp formation, and fruitbody development.
Flagellar Motility Contributes to Cytokinesis inTrypanosoma bruceiand Is Modulated by an Evolutionarily Conserved Dynein Regulatory System
Authors: Ralston Katherine S. , Lerner Alana G. , Diener Dennis R. , Hill Kent L. 
Published: April 2006

ABSTRACTThe flagellum ofTrypanosoma bruceiis a multifunctional organelle with critical roles in motility and other aspects of the trypanosome life cycle. Trypanin is a flagellar protein required for directional cell motility, but its molecular function is unknown. Recently, a trypanin homologue inChlamydomonas reinhardtiiwas reported to be part of a dynein regulatory complex (DRC) that transmits regulatory signals from central pair microtubules and radial spokes to axonemal dynein. DRC genes were identified as extragenic suppressors of central pair and/or radial spoke mutations. We used RNA interference to ablate expression of radial spoke (RSP3) and central pair (PF16) components individually or in combination with trypanin. Bothrsp3andpf16single knockdown mutants are immotile, with severely defective flagellar beat. In the case ofrsp3, this loss of motility is correlated with the loss of radial spokes, while in the case ofpf16the loss of motility correlates with an aberrant orientation of the central pair microtubules within the axoneme. Genetic interaction between trypanin and PF16 is demonstrated by the finding that loss of trypanin suppresses thepf16beat defect, indicating that the DRC represents an evolutionarily conserved strategy for dynein regulation. Surprisingly, we discovered that four independent mutants with an impaired flagellar beat all fail in the final stage of cytokinesis, indicating that flagellar motility is necessary for normal cell division inT. brucei. These findings present the first evidence that flagellar beating is important for cell division and open the opportunity to exploit enzymatic activities that drive flagellar beat as drug targets for the treatment of African sleeping sickness.
Endoplasmic Reticulum-Associated Degradation Is Required for Cold Adaptation and Regulation of Sterol Biosynthesis in the Yeast
Saccharomyces cerevisiae
Authors: Loertscher Jennifer , Larson Lynnelle L. , Matson Clinton K. , Parrish Mark L. , Felthauser Alicia , Sturm Aaron , Tachibana Christine , Bard Martin , Wright Robin 
Published: April 2006

ABSTRACT

Endoplasmic reticulum-associated degradation (ERAD) mediates the turnover of short-lived and misfolded proteins in the ER membrane or lumen. In spite of its important role, only subtle growth phenotypes have been associated with defects in ERAD. We have discovered that the ERAD proteins Ubc7 (Qri8), Cue1, and Doa10 (Ssm4) are required for growth of yeast that express high levels of the sterol biosynthetic enzyme, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Interestingly, the observed growth defect was exacerbated at low temperatures, producing an HMGR-dependent cold sensitivity. Yeast strains lacking
UBC7
,
CUE1
, or
DOA10
also assembled aberrant karmellae (ordered arrays of membranes surrounding the nucleus that assemble when HMGR is expressed at high levels). However, rather than reflecting the accumulation of abnormal karmellae, the cold sensitivity of these ERAD mutants was due to increased HMGR catalytic activity. Mutations that compromise proteasomal function also resulted in cold-sensitive growth of yeast with elevated HMGR, suggesting that improper degradation of ERAD targets might be responsible for the observed cold-sensitive phenotype. However, the essential ERAD targets were not the yeast HMGR enzymes themselves. The sterol metabolite profile of
ubc7Δ
cells was altered relative to that of wild-type cells. Since sterol levels are known to regulate membrane fluidity, the viability of ERAD mutants expressing normal levels of HMGR was examined at low temperatures. Cells lacking
UBC7
,
CUE1
, or
DOA10
were cold sensitive, suggesting that these ERAD proteins have a role in cold adaptation, perhaps through effects on sterol biosynthesis.
Phosphoinositide 5-Phosphatase Fig4p Is Required for both Acute Rise and Subsequent Fall in Stress-Induced Phosphatidylinositol 3,5-Bisphosphate Levels
Authors: Duex Jason E. , Nau Johnathan J. , Kauffman Emily J. , Weisman Lois S. 
Published: April 2006

ABSTRACT

Phosphoinositide lipids regulate complex events via the recruitment of proteins to a specialized region of the membrane at a specific time. Precise control of both the synthesis and turnover of phosphoinositide lipids is integral to membrane trafficking, signal transduction, and cytoskeletal rearrangements. Little is known about the acute regulation of the levels of these signaling lipids. When
Saccharomyces cerevisiae
cells are treated with hyperosmotic medium the levels of phosphatidylinositol 3,5-bisphosphate (PI3,5P
2
) increase 20-fold. Here we show that this 20-fold increase is rapid and occurs within 5 min. Surprisingly, these elevated levels are transient. Fifteen minutes following hyperosmotic shock they decrease at a rapid rate, even though the cells remain in hyperosmotic medium. In parallel with the rapid increase in the levels of PI3,5P
2
, vacuole volume decreases rapidly. Furthermore, concomitant with a return to basal levels of PI3,5P
2
vacuole volume is restored. We show that Fig4p, consistent with its proposed role as a PI3,5P
2
5-phosphatase, is required in vivo for this rapid return to basal levels of PI3,5P
2
. Surprisingly, we find that Fig4p is also required for the hyperosmotic shock-induced increase in PI3,5P
2
levels. These findings demonstrate that following hyperosmotic shock, large, transient changes occur in the levels of PI3,5P
2
and further suggest that Fig4p is important in regulating both the acute rise and subsequent fall in PI3,5P
2
levels.
Activation of Zoosporogenesis-Specific Genes in
Phytophthora infestans
Involves a 7-Nucleotide Promoter Motif and Cold-Induced Membrane Rigidity
Authors: Tani Shuji , Judelson Howard 
Published: April 2006

ABSTRACT

Infections of plants by the oomycete
Phytophthora infestans
typically result from zoospores, which develop from sporangia at cold temperatures. To help understand the relevant cold-induced signaling pathway, factors regulating the transcription of the zoosporogenesis-specific NIF (nuclear LIM-interactor-interacting factor) gene family were examined. Sequences required for inducing
PinifC3
were identified by analyzing truncated and mutated promoters using the β-glucuronidase reporter in stable transformants. A 7-nucleotide (nt) sequence located 139 bases upstream of the major transcription start point (GGACGAG) proved essential for the induction of
PinifC3
when sporangia were shifted from ambient to cold temperatures. The motif, named the cold box, also conferred cold inducibility to a promoter normally activated only during sexual development. An identical motif was detected in the two other zoosporogenesis-specific NIF genes from
P. infestans
and three
Phytophthora sojae
orthologues, and a closely related sequence was found in
Phytophthora ramorum
orthologues. The 7-nt motif was also found in the promoters of other zoosporogenesis-induced genes. The presence of a cold box-interacting protein in nuclear extracts of
P. infestans
sporangia was demonstrated using electrophoretic mobility shift assays. Furthermore, zoospore release and cold box-regulated transcription were stimulated by the membrane rigidizer dimethyl sulfoxide and inhibited by the membrane fluidizer benzyl alcohol. The data therefore delineate a pathway in which sporangia perceive cold temperatures through membrane rigidity, which activates signals that drive both zoosporogenesis and cold-box-mediated transcription.
Specific Effects of Ribosome-Tethered Molecular Chaperones on Programmed −1 Ribosomal Frameshifting
Authors: Muldoon-Jacobs Kristi L. , Dinman Jonathan D. 
Published: April 2006

ABSTRACT

The ribosome-associated molecular chaperone complexes RAC (Ssz1p/Zuo1p) and Ssb1p/Ssb2p expose a link between protein folding and translation. Disruption of the conserved nascent peptide-associated complex results in cell growth and translation fidelity defects. To better understand the consequences of deletion of either RAC or Ssb1p/2p, experiments relating to cell growth and programmed ribosomal frameshifting (PRF) were assayed. Genetic analyses revealed that deletion of Ssb1p/Ssb2p or of Ssz1p/Zuo1p resulted in specific inhibition of −1 PRF and defects in Killer virus maintenance, while no effects were observed on +1 PRF. These factors may provide a new set of targets to exploit against viruses that use −1 PRF. Quantitative measurements of growth profiles of isogenic wild-type and mutant cells showed that translational inhibitors exacerbate underlying growth defects in these mutants. Previous studies have identified −1 PRF signals in yeast chromosomal genes and have demonstrated an inverse relationship between −1 PRF efficiency and mRNA stability. Analysis of published DNA microarray experiments reveals conditions under which Ssb1, Ssb2, Ssz1, and Zuo1 transcript levels are regulated independently of those of genes encoding ribosomal proteins. Thus, the findings presented here suggest that these
trans
-acting factors could be used by cells to posttranscriptionally regulate gene expression through −1 PRF.
Cardiolipin in Hydrogenosomes: Evidence of Symbiotic Origin
Authors: de Andrade Rosa Ivone , Einicker-Lamas Marcelo , Roney Bernardo Róbson , Previatto Lucia Mendonça , Mohana-Borges Ronaldo , Morgado-Díaz José Andrés , Benchimol Marlene 
Published: April 2006

ABSTRACT

Hydrogenosomes are found in organisms that lack typical mitochondria. Cardiolipin is a phospholipid located exclusively in bacterial membranes and the inner membrane of mitochondria. Here we show, by cell fractionation, thin-layer chromatography, high-pressure liquid chromatography, and matrix-assisted laser desorption ionization-time of flight mass spectrometry that hydrogenosomes of
Tritrichomonas foetus
, a cattle vaginal parasite, contain cardiolipin, which is strong evidence for its endosymbiotic origin.
Gewalt und Religion. Eine religionswissenschaftliche Untersuchung zu den anthropologischen Ursachen und kulturellen Überformungen der Gewaltanwendung unter Menschen
Authors: Bumbacher Stephan Peter 
Published: April 2006

AbstractIntra-species killing occurs in all known human societies as well as among chimpanzees as wars between different groups. This parallel may be the product of a common evolution as both species are the closest biological relatives. Unlike apes, however, human beings not only compete for territories but also for power in general, goods, etc. As the product of mankind's further evolution, religions legitimate this inter-group violence.
A Simple Method for the Assessment of the Cloud Cover State in High-Latitude Regions by a Ground-Based Digital Camera
Authors: Souza-Echer M. P. , Pereira E. B. , Bins L. S. , Andrade M. A. R. 
Published: April 2006

Abstract
This work describes the development of a simple method of field estimating the sky cloud coverage percentage for several applications at the Brazilian Antarctic Station, Ferraz (62°05′S, 58°23.5′W). The database of this method was acquired by a digital color camera in the visible range of the spectrum. A new algorithm was developed to classify each pixel according to a criteria decision process. The information on the pixel contamination by clouds was obtained from the saturation component of the intensity, hue, and saturation space (IHS). For simplicity, the images were acquired with a limited field of view of 36° pointing to the camera’s zenith to prevent direct sunlight from reaching the internal charge-coupled device (CCD) on the camera. For a priori–classified clear-sky images, the accuracy of the method was superior to 94%. For overcast-sky conditions, the corresponding accuracy was larger than 99%.
A comparison test was performed with two human observers and our method. The results for the 29 images collected for several time of days during 50 days in 1999 summer were compared to visual observations of these same digital images by two trained field meteorologists. Correlation coefficients between human observers and the automatic method ranged from 0.84 for clear-sky conditions, and the lowest was 0.09 for undefined-sky conditions.
Toward Estimating Climatic Trends in SST. Part I: Methods of Measurement
Authors: Kent Elizabeth C. , Taylor Peter K. 
Published: April 2006

Abstract
To assess climatic changes in sea surface temperature (SST), changes in the measurement method with time and the effect of these changes on the mean SST must be quantified. Observations from the International Comprehensive Ocean–Atmosphere Data Set (ICOADS) have been analyzed for the period from 1970 to 1997 using both SST measurement metadata contained within the dataset and a World Meteorological Organization (WMO) catalog of observing ships. The WMO metadata were particularly important in identifying engine-intake SSTs during the 1970s, but increased method identification over the entire period. There are strong regional variations in the preferred SST measurement method, with engine-intake SST most common in the Pacific and bucket SST preferred by countries bordering the Atlantic. The number of engine-intake SSTs increases over time and becomes more numerous than buckets by the early 1980s.
There are significant differences between SST observations made by different methods. The rounding of reports is more common for engine-intake SST than for either bucket or hull sensor SST, which degrades its quality. Significant time-varying biases exist between SST derived from buckets and from engine intakes. The SST difference has a strong seasonal signal with bucket SST being relatively cold in winter, probably resulting from heat loss from the buckets, and warm in summer, probably resulting from solar warming or the sampling of a shallow warm layer. There is also a long-term trend with engine-intake SST being relatively warm in the early period but with a small annual mean difference between the two methods by 1990.
Toward Estimating Climatic Trends in SST. Part II: Random Errors
Authors: Kent Elizabeth C. , Challenor Peter G. 
Published: April 2006

Abstract
Random observational errors for sea surface temperature (SST) are estimated using merchant ship reports from the International Comprehensive Ocean–Atmosphere Data Set (ICOADS) for the period of 1970–97. A statistical technique, semivariogram analysis, is used to isolate the variance resulting from the observational error from that resulting from the spatial variability in a dataset of the differences of paired SST reports. The method is largely successful, although there is some evidence that in high-variability regions the separation of random and spatial error is not complete, which may have led to an overestimate of the random observational error in these regions. The error estimates are robust to changes in the details of the regression method used to estimate the spatial variability.
The resulting error estimates are shown to vary with region, time, the quality control applied, the method of measurement, the recruiting country, and the source of the data. SST data measured using buckets typically contain smaller random errors than those measured using an engine-intake thermometer. Errors are larger in the 1970s, probably because of problems with data transmission in the early days of the Global Telecommunications System. The best estimate of the global average random error in ICOADS ship SST for the period of 1970–97 is 1.2°C if the estimates are weighted by ocean area and 1.3°C if the estimates are weighted by the number of observations.
Toward Estimating Climatic Trends in SST. Part III: Systematic Biases
Authors: Kent Elizabeth C. , Kaplan Alexey 
Published: April 2006

Abstract
A method is developed to quantify systematic errors in two types of sea surface temperature (SST) observations: bucket and engine-intake measurements. A simple linear model is proposed where the SST measured using a bucket is cooled or warmed by a fraction of the air–sea temperature difference and the SST measured using an engine intake has a constant bias. The model is applied to collocated nighttime observations made at moderate wind speeds, allowing the effects of solar radiation and strong vertical gradients in the upper ocean to be neglected. The analysis is complicated by large random errors in all of the variables used. To estimate coefficients in this model, a novel type of linear regression, where errors in two variables are correlated with each other, is introduced. Because of the uncertainty in a priori estimates of the error covariance matrix, a Bayesian analysis of the regression problem is developed, and maximum likelihood approximations to the posterior distributions of the model parameters are obtained.
Results show that the temperature change in bucket SST resulting from the air–sea temperature difference can be detected. The analysis suggests that bucket SST may be in error by a fraction from 0.12° ± 0.02° to 0.16° ± 0.02°C of the air–sea temperature difference. When this temperature change of the bucket SST is accounted for, a warm bias in engine-intake SST in the mid- to late 1970s and the 1980s was found to be smaller than that suggested by previous studies, ranging between 0.09° ± 0.06° and 0.18° ± 0.05°C. For the early 1990s the model suggests that the engine-intake SSTs may have a cold bias of −0.13° ± 0.07°C.
Row-Action Inversion of the Barrick–Weber Equations
Authors: Green J. J. , Wyatt L. R. 
Published: April 2006

Abstract
The Barrick–Weber equations describe the interaction of radar signals with the dynamic ocean surface, and so provide a mathematical basis for oceanic remote sensing. This report considers the inversion of these equations with several of the row-action methods commonly used to solve large linear systems with unstructured sparsity. It is found that the performance of the methods in inverting both synthetic and measured Doppler spectral data is comparable, with the method of Chahine–Twomey–Wyatt offering a slight advantage in the reliability of the recovery of the full directional wave spectrum and of parameters derived from its integration. Some remarks and open questions on the ill-posedness of the inversion problem conclude the paper.