bluuebunny/crossref_metadata_2025_split huggingface dataset:
The
Escherichia coli
Regulator of Sigma 70 Protein, Rsd, Can Up-Regulate Some Stress-Dependent Promoters by Sequestering Sigma 70
Authors: Mitchell Jennie E. , Oshima Taku , Piper Sarah E. , Webster Christine L. , Westblade Lars F. , Karimova Gouzel , Ladant Daniel , Kolb Annie , Hobman Jon L. , Busby Stephen J. W. , Lee David J. 
Published: March 2007

ABSTRACT

The
Escherichia coli
Rsd protein forms complexes with the RNA polymerase σ
70
factor, but its biological role is not understood. Transcriptome analysis shows that overexpression of Rsd causes increased expression from some promoters whose expression depends on the alternative σ
38
factor, and this was confirmed by experiments with
lac
fusions at selected promoters. The LP18 substitution in Rsd increases the Rsd-dependent stimulation of these promoter-
lac
fusions. Analysis with a bacterial two-hybrid system shows that the LP18 substitution in Rsd increases its interaction with σ
70
. Our experiments support a model in which the role of Rsd is primarily to sequester σ
70
, thereby increasing the levels of RNA polymerase containing the alternative σ
38
factor.
XphA/XqhA, a Novel GspCD Subunit for Type II Secretion in
Pseudomonas aeruginosa
Authors: Michel Gérard P. F. , Durand Eric , Filloux Alain 
Published: March 2007

ABSTRACT

The opportunistic human pathogen bacterium
Pseudomonas aeruginosa
secretes various exoproteins in its surrounding environment. Protein secretion involves different secretory systems, including the type II secretion system, or T2SS, that is one of the most efficient secretory pathways of
P. aeruginosa
. There are two T2SS in this bacterium, the quorum-sensing-regulated Xcp system and the Hxc system, which is only present under phosphate-limiting conditions. Like T2SS of other bacteria, the Xcp T2SS is species specific, and this specificity mainly involves two proteins, XcpP (GspC family) and the secretin XcpQ (GspD family), which are the gatekeepers of the system. Interestingly, an orphan secretin, XqhA, was previously reported as being able to functionally replace the XcpQ secretin. In this study, we identified another gene, which we named
xphA
(
x
cp
P h
omologue
A
), which is located next to
xqhA
. We showed that deletion of the
xphA
gene in an
xcpP
mutant caused the disappearance of the residual secretion observed in this mutant strain, indicating that the protein XphA plays a role in the secretion process. Our results also revealed that complementation of an
xcpP/xcpQ
mutant can be obtained with the gene couple
xphA/xqhA
. The XphA and XqhA proteins (the P
A
Q
A
subunit) could thus form, together with XcpR-Z, a functional hybrid T2SS. A two-dimensional polyacrylamide gel electrophoresis analysis showed that except for the aminopeptidase PaAP, for which secretion is not restored by the P
A
Q
A
subunit in the
xcpP/xcpQ
deletion mutant, each major Xcp-dependent exoprotein is secreted by the new hybrid machinery. Our work supports the idea that components of the GspC/GspD families, such as XphA/XqhA or XcpP/XcpQ, are assembled as a specific tandem within the T2SS. Each of these pairs may thus confer a different level of secretion specificity, as is the case with respect to PaAP. Finally, using a chromosomal
xphA
-
lacZ
fusion, we showed that the
xphA-xqhA
genes are transcribed from an early stage of bacterial growth. We thus suggest that the P
A
Q
A
subunit might be involved in the secretion process at a different growth stage than XcpP/XcpQ.
MarT Activates Expression of the MisL Autotransporter Protein of
Salmonella enterica
Serotype Typhimurium
Authors: Tükel Çagla , Akçelik Mustafa , de Jong Maarten F. , Şimşek Ömer , Tsolis Renée M. , Bäumler Andreas J. 
Published: March 2007

ABSTRACT

MisL is a
Salmonella enterica
serotype Typhimurium fibronectin binding protein whose expression is induced during infection of mice. T-POP transposon mutagenesis identified
marT
as a positive regulatory element controlling expression of a
misL
::
lacZYA
transcriptional fusion. Gel shift analysis identified MarT as a transcriptional activator of the
misL
promoter.
Identification of Critical Residues in the Propeptide of LasA Protease of
Pseudomonas aeruginosa
Involved in the Formation of a Stable Mature Protease
Authors: Grande Kerian K. , Gustin Jean K. , Kessler Efrat , Ohman Dennis E. 
Published: March 2007

ABSTRACT

LasA protease is a 20-kDa elastolytic and staphylolytic enzyme secreted by
Pseudomonas aeruginosa
. LasA is synthesized as a preproenzyme that undergoes proteolysis to remove a 22-kDa amino-terminal propeptide. Like the propeptides of other bacterial proteases, the LasA propeptide may act as an intramolecular chaperone that correctly folds the mature domain into an active protease. To locate regions of functional importance within proLasA, linker-scanning insertional mutagenesis was employed using a plasmid containing
lasA
as the target. Among the 5 missense insertions found in the mature domain of proLasA, all abolished enzymatic activity but not secretion. In general, the propeptide domain was more tolerant to insertions. However, insertions within a 9-amino-acid region in the propeptide caused dramatic reductions in LasA enzymatic activity. All mutant proLasA proteins were still secreted, but extracellular stability was low due to clustered insertions within the propeptide. The codons of 16 residues within and surrounding the identified 9-amino-acid region were subjected to site-directed mutagenesis. Among the alanine substitutions in the propeptide that had a major effect on extracellular LasA activity, two (L92A and W95A) resulted in highly unstable proteins that were susceptible to proteolytic degradation and three (H94A, I101A, and N102A) were moderately unstable and allowed the production of a LasA protein with low enzymatic activity. These data suggest that these clustered residues in the propeptide may play an important role in promoting the correct protein conformation of the mature LasA protease domain.
Biosynthesis of Isoprenoid Wax Ester inMarinobacter hydrocarbonoclasticusDSM 8798: Identification and Characterization of Isoprenoid Coenzyme A Synthetase and Wax Ester Synthases
Authors: Holtzapple Erik , Schmidt-Dannert Claudia 
Published: March 2007

ABSTRACTMarinobacter hydrocarbonoclasticusDSM 8798 has been reported to synthesize isoprenoid wax ester storage compounds when grown on phytol as the sole carbon source under limiting nitrogen and/or phosphorous conditions. We hypothesized that isoprenoid wax ester synthesis involves (i) activation of an isoprenoid fatty acid by a coenzyme A (CoA) synthetase and (ii) ester bond formation between an isoprenoid alcohol and isoprenoyl-CoA catalyzed, most likely, by an isoprenoid wax ester synthase similar to an acyl wax ester synthase, wax ester synthase/diacylglycerol acyltransferase (WS/DGAT), recently described fromAcinetobactersp. strain ADP1. We used the recently released rough draft genome sequence of a closely related strain,M. aquaeoleiVT8, to search for WS/DGAT and acyl-CoA synthetase candidate genes. The sequence information from putative WS/DGAT and acyl-CoA synthetase genes identified in this strain was used to clone homologues from the isoprenoid wax ester synthesizingMarinobacterstrain. The activities of the recombinant enzymes were characterized, and two new isoprenoid wax ester synthases capable of synthesizing isoprenoid ester and acyl/isoprenoid hybrid ester in vitro were identified along with an isoprenoid-specific CoA synthetase. One of theMarinobacterwax ester synthases displays several orders of magnitude higher activity toward acyl substrates than any previously characterized acyl-WS and may reflect adaptations to available carbon sources in their environments.
VEGF-C is associated with lymphatic status and invasion in oral cancer
Authors: Siriwardena B S M S , Kudo Y , Ogawa I , Udagama M N G P K , Tilakaratne W M , Takata T 
Published: March 2007

Background:Nodal metastasis is a major prognostic indicator for oral squamous cell carcinoma (OSCC) progression. Recently, it has been revealed that lymphangiogenic growth factor VEGF-C and its receptor Flt-4 play an important role for invasion and metastasis in cancer cells.Aim:To examine VEGF-C expression and its correlation with lymphatic status, including the number of lymph vessels and lymphatic invasion, tumour invasion and metastasis in OSCC.Methods:Intratumoural and peritumoural lymphatic vessels were examined using D2-40 in 54 OSCC cases and correlated with VEGF-C expression and clinicopathological findings. The histological pattern of invasion and pathological findings were compared.Results:High expression of VEGF-C was frequently observed in OSCC and was associated with increased number of lymph vessels and lymphatic invasion. VEGF-C was well correlated with invasion pattern and metastasis.Conclusions:Results suggest that VEGF-C may play an important role for lymphangiogenesis and invasion in the metastatic process and can be a strong predicting factor for metastasis of OSCC.
Catastrophic Head Injuries in High School and College Football Players
Authors: Boden Barry P. , Tacchetti Robin L. , Cantu Robert C. , Knowles Sarah B. , Mueller Frederick O. 
Published: March 2007

Background Catastrophic head injuries in football are rare but tragic events. Purpose To update the profile of catastrophic head injuries in high school and college football players and to describe relevant risk factors. Study Design Case series; Level of evidence, 4. Methods We reviewed 94 incidents of severe football head injuries reported to the National Center for Catastrophic Sports Injury Research during 13 academic years (September 1989 through June 2002). Results In the study period there were an average of 7.23 (standard deviation = 2.05) direct high school and college catastrophic head injuries in scholastic football participants per year. There were 0.67 injuries per 100 000 (95% confidence interval: 0.54, 0.81 per 100 000) high school and 0.21 injuries per 100 000 (95% confidence interval: 0.0, 0.49 per 100 000) college participants for a risk ratio of 3.28 (95% confidence interval: 0.81, 13.3). The injuries resulted in subdural hematoma in 75 athletes, subdural hematoma with diffuse brain edema in 10 athletes, diffuse brain edema in 5 athletes, and arteriovenous malformation or aneurysm in 4 athletes. Fifty-nine percent of the contacts reported that the athlete had a history of a previous head injury, of which 71% occurred within the same season as the catastrophic event. Thirty-nine percent of the athletes (21 of 54) were playing with residual neurologic symptoms from the prior head injury. There were 8 (9%) deaths as a result of the injury, 46 (51%) permanent neurologic injuries, and 36 (40%) serious injuries with full recovery. Most players sustained a major impact to the head either from tackling or being tackled. Conclusion The incidence of catastrophic head injuries in football has remained low since the advent of the modern day football helmet in the early 1970s. The incidence of catastrophic head injuries in football is dramatically higher at the high school level than at the college level. Although the reason for this discrepancy is unclear, an unacceptably high percentage of high school players were playing with residual symptoms from a prior head injury. Coaches, athletes, athletic trainers, and medical personnel need to adhere to the guideline that an athlete with any neurologic symptoms from a head injury should be strongly discouraged from returning to play.
ERK1/2 phosphorylation is an independent predictor of complete remission in newly diagnosed adult acute lymphoblastic leukemia
Authors: Gregorj Chiara , Ricciardi Maria R. , Petrucci Maria T. , Scerpa Maria C. , De Cave Fabiana , Fazi Paola , Vignetti Marco , Vitale Antonella , Mancini Marco , Cimino Giuseppe , Palmieri Salvatore , Di Raimondo Francesco , Specchia Giorgina , Fabbiano Francesco , Cantore Nicola , Mosna Federico , Camera Andrea , Luppi Mario , Annino Luciana , Miraglia Eustachio , Fioritoni Giuseppe , Ronco Francesca , Meloni Giovanna , Mandelli Franco , Andreeff Michael , Milella Michele , Foà Robin , Tafuri Agostino 
Published: March 2007

Abstract
Extracellular signal-regulated kinase-1/2 (ERK1/2) is frequently found constitutively activated (p-ERK1/2) in hematopoietic diseases, suggesting a role in leukemogenesis. The aim of this study was to assess the expression and clinical role of p-ERK1/2 in adult acute lymphoblastic leukemia (ALL). In 131 primary samples from adult de novo ALL patients enrolled in the Gruppo Italiano per le Malattie Ematologiche dell'Adulto (GIMEMA) Leucemia Acute Linfoide (LAL) 2000 protocol and evaluated by flow cytometry, constitutive ERK1/2 activation was found in 34.5% of cases; these results were significantly associated with higher white blood cell (WBC) values (P = .013). In a multivariate analysis, p-ERK1/2 expression was an independent predictor of complete remission achievement (P = .027). Effective approaches toward MEK inhibition need to be explored in order to evaluate whether this may represent a new therapeutic strategy for adult ALL patients.
A novel proteoliposomal vaccine elicits potent antitumor immunity in mice
Authors: Popescu Mircea C. , Robb Richard J. , Batenjany Michael M. , Boni Lawrence T. , Neville Mary E. , Pennington Robin W. , Neelapu Sattva S. , Kwak Larry W. 
Published: March 2007

AbstractTherapeutic vaccination against idiotype is a promising strategy for immunotherapy of B-cell malignancies. Its feasibility, however, is limited by the requirement for a patient-specific product. Here we describe a novel vaccine formulation prepared by simply extracting cell-membrane proteins from lymphoma cells and incorporating them together with IL-2 into proteoliposomes. The vaccine was produced in 24 hours, compared with more labor-intensive and time-consuming hybridoma or recombinant DNA methods. The vaccine elicited T-cell immunity in vivo, as demonstrated by secretion of type 1 cytokines. It protected against tumor challenge at doses of tumor antigen 50 to 100 times lower than that previously observed using either liposomes formulated with IL-2 and secreted lymphoma immunoglobulin or a prototype vaccine consisting of lymphoma immunoglobulin conjugated to keyhole limpet hemocyanin. The increased potency justifies testing similar patient-specific human vaccines prepared using extracts from primary tumor samples.
A phase 2 study of the oral farnesyltransferase inhibitor tipifarnib in patients with refractory or relapsed acute myeloid leukemia
Authors: Harousseau Jean-Luc , Lancet Jeffrey E. , Reiffers Josy , Lowenberg Bob , Thomas Xavier , Huguet Francoise , Fenaux Pierre , Zhang Steven , Rackoff Wayne , De Porre Peter , Stone Richard 
Published: March 2007

AbstractThis phase 2 study evaluated the efficacy and safety of the oral farnesyltransferase inhibitor tipifarnib in adults with refractory or relapsed acute myeloid leukemia (AML). Patients (n = 252) received tipifarnib 600 mg twice a day for 21 days in 28-day cycles. Median age was 62 years; 99 (39%) patients were 65 years or older. Eleven (4%) of 252 patients achieved complete remission (CR) or complete remission with incomplete platelet recovery (CRp; 9 CR and 2 CRp). Nineteen patients (8%), including those who achieved CR/CRp, achieved a reduction in bone marrow blasts to less than 5% blasts. Bone marrow blasts were reduced more than 50% in an additional 8 patients (total = 27; 11%). Median survival was 369 days for patients who achieved CR/CRp. Myelosuppression was the most common adverse event. The most common nonhematologic toxicities were fever, nausea, and hypokalemia. Single-agent treatment with tipifarnib induced durable CR/CRp, which was associated with prolonged survival, in some patients with refractory or relapsed AML. The response rate observed in this heavily pretreated group of patients suggests the requirement to enhance the response rate either by combining tipifarnib with other active agents or determining factors that are predictive of response.
Reciprocal effects of IFN-β and IL-12 on STAT4 activation and cytokine induction in T cells
Authors: Fahey Angela J , Robins R Adrian , Constantinescu Cris S 
Published: March 2007

AbstractIL-12 is an immunoregulatory cytokine, which promotes Th1 cell differentiation and is a major inducer of IFN-γ. IFN-β, a Type I IFN used in the treatment of multiple sclerosis, has been shown to significantly increase the expression of the anti-inflammatory cytokine IL-10, a major suppressor of Th1 cytokines. The beneficial immunomodulatory effects of IFN-β may in part be a result of its ability to suppress IL-12. However, IL-12 and IFN-β signal via the STAT4 pathway. Our aim was to investigate the relationship between IL-12 and IFN-β by observing the effect of prior exposure to IL-12 or IFN-β on the ability of T cells to subsequently respond to the other cytokine. We report that IFN-β increases IL-12-induced STAT4 phosphorylation and up-regulates IL-12 receptor β1 and β2 expression. However, despite this up-regulation, IFN-β suppressed IL-12-induced IFN-γ expression. Our results suggest that this may be a result of the parallel induction of IL-10 by IFN-β.
University students' academic performance: An integrative conceptual framework and empirical analysis
Authors: Fenollar Pedro. , Román Sergio. , Cuestas Pedro J. 
Published: March 2007

Background. The prediction and explanation of academic performance and the investigation of the factors relating to the academic success and persistence of students are topics of utmost importance in higher education.Aims. The main aim of the present study is to develop and test a conceptual framework in a university context, where the effects of achievement goals, self‐efficacy and class size on academic performance are hypothesized to be direct and indirect through study strategies.Sample. Participants were 553 students of different faculties from a university in Spain.Method. Pre‐existing scales were used to develop the questionnaire. Questionnaires were group‐administered in 21 classes during the first 2 weeks of May (i.e. about 1 month before the final examination). At the end of the academic year, students' grades were obtained from professors of each course.Results. Data were analysed through structural equation modelling. The results of the structural model provided support for most of the hypothesized relationships. Achievement goals and self‐efficacy had no direct effects on performance, but results from the model comparison suggested that a mediational model provided a better fit to the data.Conclusions. Our study provides support for the key mediational role of study strategies in the effect of achievement goals and self‐efficacy on academic performance. Self‐efficacy seems to have the strongest indirect effect on performance. Mastery goals play a key role increasing deep processing and effort, and in turn affecting performance. Academic performance tends to diminish with increasing class size.
Plans for the 1970 census of population and housing
Authors: Kaplan David L. 
Published: March 2007

Abstract
The Nineteenth Decennial Census of the United States, covering both population and housing, will be conducted as of April 1, 1970. Planning, testing, and preparatory activities have been underway since early in the decade. Extensive discussions with users of census data led to relatively minor changes in subject content as compared to 1960, but a major increase in the amount of statistics to be tabulated, especially for small geographic areas. For about 60 to 65 percent of the population, the information will be collected through a new mail-out/mail-back system. The rest of the country will be covered by house-to-house canvass. Special efforts to alleviate the serious problem of underenumeration are being undertaken, particularly in the hard-to-enumerate portions of the big cities. The geographic program includes an “address coding guide” through which location identification in most urban areas can be made to specific side of block; this will permit tabulations for new types of small areas. Processing of the data will be performed with the Census Bureau’s Fosdic equipment and advanced computers. Dissemination of the census results will be in the traditional type of printed reports but also, in substantially greater subject and area detail, through magnetic tape, special printouts, etc. To help users exploit the potentialities of the latter material, the Bureau has instituted a “data access” informational program. As in previous censuses, there will be a number of studies to evaluate the 1970 procedures and results.
The end of rapid increase in the use of oral anovulants? Some problems in the interpretation of time series of oral use among married women
Authors: Allingham John D. , Balakrishnan T. R. , Kantner John F. 
Published: March 2007

Abstract
Several problems in the interpretation of time series of oral anovulant usage are discussed, among them the shifting marriage-duration distribution over time. Standardization fails to negate the conclusion that the rate of increase in the proportion of women using orals has slackened since January 1966. Separate analyses by duration-specific rates of use and by marriage cohorts show that the two factors sustaining the initial spectacular growth rate in the use of orals-the ever—higher initial use rates of new marriage cohorts and the rapid adoption of orals among earlier cohorts at later durations—have lost their sustaining force. Further analysis indicates that concern over the pill as a health hazard is a major deterrent to substantial increase in oral usage. A final distribution of women by risk status with respect to oral use, and current and prospective oral use, shows that under present circumstances the maximum oral use rate will be considerably less than unity.
Recent changes in Negro fertility
Authors: Farley Reynolds 
Published: March 2007

Abstract
Crude birth rates for the Negro population of the United States indicate that fertility declined while Negroes remained in the South and them climbed in the last twenty-five years as Negroes became urbanized. Cohort rates show more precisely the effects of the Depression upon childbearing as well as the magnitude and persistence of the post-Depression rise in fertility. More Negro women now become mothers, average family size has increased, and the proportion of women bearing six, seven, or eight children has risen. Negro fertility has risen despite the urbanization of Negroes and improvements in their socio-economic characteristics.
Negro fertility rates present the paradox of falling when demographic transition theory would predict the maintenance of high rates and then rising when a decline would be expected. Urbanization does not appear to have reduced Negro fertility.
Traditionally, urban living has dampened childbearing in two ways—first, health conditions in cities were inferior to those of rural areas, and thus urbanization affected fecundity adversely; second, city residents are more likely to know about and adopt birth control than rural residents.
Negroes migrated to cities at the very time when diseases were being controlled and when public health and welfare facilities were being expanded to serve all residents. This has contributed to higher Negro fertility rates. If fertility rates are to fall because of family planning, not only must birth control be available but there must be a desire to limit family size. Such a desire may be linked to opportunities for social mobility. Negroes have not been assimilated into urban society as previous in-migrant groups were, and opportunities for mobility have been restricted. For these reasons Negroes may be slow to adopt stable monogamous families and the intentional control of fertility.