bluuebunny/crossref_metadata_2025 huggingface dataset:
Faculty Development in Geriatrics for Clinician Educators: A Unique Model for Skills Acquisition and Academic Achievement
Authors: Levine Sharon A. , Caruso Lisa B. , Vanderschmidt Hannelore , Silliman Rebecca A. , Barry Patricia P.
Published: February 2005

As the size of the aged American population increases, so too does the shortage of trained providers in geriatrics. Educational strategies to train physicians at all levels of experience within adult medical and surgical disciplines are needed to complement fellowship training, given the small size of most academic faculties in geriatrics. This article describes a unique faculty development program that creates geriatrically oriented faculty in multiple disciplines. The Boston University Center of Excellence in Geriatrics (COE), funded by the John A. Hartford Foundation, has trained 25 faculty members. Four to six scholars enter the program each year and participate in the COE 1 day per week. Nine months are spent in four content modules—Geriatrics Content, Clinical Teaching, Evidence‐based Medicine, and Health Care Systems; 3 months are spent in supervised scholarly activities and clinical settings. A self‐report questionnaire and a structured interview were used to evaluate the outcomes of participation in the COE. The results from the first 4 years of the program are reported. The response rate was 83% for the self‐report questionnaire and 75% for the structured interview. The results indicate that the COE is effective in improving scholars' assessment and management of older patients. The structured interview revealed that the COE program promotes the integration of geriatrics into clinical teaching at the medical student and resident level. Participants also completed scholarly projects in geriatrics. This program effectively trains faculty scholars to better care for older adults and to teach others to do likewise.
A New Paradigm for Clinical Investigation of Infectious Syndromes in Older Adults: Assessing Functional Status as a Risk Factor and Outcome Measure
Authors: High Kevin , Bradley Suzanne , Loeb Mark , Palmer Robert , Quagliarello Vincent , Yoshikawa Thomas
Published: February 2005

Adults aged 65 and over comprise the fastest growing segment of the U.S. population, and older adults experience greater morbidity and mortality due to infection than young adults. While this factor is well established, most clinical investigation of infectious diseases in the aged focuses on microbiology, and crude endpoints of clinical success such as cure rates or mortality, but often fails to assess functional status, a critical variable in geriatric care. Functional status can be evaluated as a risk factor for infectious disease or an outcome of interest following specific interventions utilizing well‐validated instruments. This paper outlines the currently available data suggesting a link between infection, immunity and impaired functional status in the elderly, summarizes commonly employed instruments used to determine specific aspects of functional status, and provides recommendations for a new paradigm in which clinical trials of older adults include functional assessment.
What Probability should a Jury Address?
Authors: Gardner-Medwin Tony
Published: February 2005

Probability of guilt is not the criterion on which a verdict in a criminal trial should be based, says Tony Gardner-Medwin. The courts, quite sensibly, do not even allow access to some of the background evidence on which a proper assessment of this probability should be made. He argues that a more satisfactory criterion is the probability, or degree of belief, that the evidence could have arisen without guilt.
Reflections on the Cot Death Cases
Authors: Hill Ray
Published: February 2005

Sally Clark, Angela Cannings and Trupti Patel not only suffered the tragic sudden deaths of two or more babies. They were then accused, and in the first two cases convicted, of their murder. The misuse of statistics at Sally Clark's trial hadprofound consequences, especially for her, but also for the subsequent cases. Ray Hill reflects on the statistical issues involved.
Misleading Statistics within Criminal Trials
Authors: Nobles Richard , Schiff David
Published: February 2005

Richard Nobles and David Schiff revisit the Sally Clark case and consider the presentation by non-statisticians of statistical evidence in court.
Interesting Times for Official Statistics
Authors: Rhind David
Published: February 2005

The Statistics Commission was set up in 2000 to monitor the production of official statistics in the UK. Professor David Rhind was one of the founding Commissioners, and has been Chairman since 2003. He tells Helen Joyce that he hasn't had a quiet moment since.
EFFECTS OF ENDPOINT TEMPERATURE, pH, AND STORAGE TIME ON COOKED INTERNAL COLOR REVERSION OF PORK LONGISSIMUS CHOPS
Authors: MANCINI R.A. , KROPF D.H. , HUNT M.C. , JOHNSON D.E.
Published: February 2005

This project evaluated the internal cooked color changes that occurred during postcooking storage of pork loin chops (m. longissimus thoracis et lumborum, n = 120) from one of six combinations of three endpoint temperatures (71.1, 76.6 and 82.2C) and two pH groups (lower, 5.4–5.5 and higher, 5.6–5.7). Initial internal color (L*a*b*), and 24 and 48 h storage (4C) pink color development were evaluated after cooking. Although pH had no effect (P > 0.05) on initial cooked color, chops with higher pH were more red (P < 0.05) and had more pink color development during storage. Increased endpoint temperature decreased (P < 0.05) initial a* values. During storage, chops from all endpoint temperatures developed a pink color with chops cooked to 76.6C having the largest increase in a*. Of the three endpoint temperatures, cooking to 82.2C minimized pink color development in cooked, uncured pork loin chops.
The Restoration Potential of the Mesopotamian Marshes of Iraq
Authors: Richardson Curtis J. , Reiss Peter , Hussain Najah A. , Alwash Azzam J. , Pool Douglas J.
Published: February 2005

Uncontrolled releases of Tigris and Euphrates River waters after the 2003 war have partially restored some former marsh areas in southern Iraq, but restoration is failing in others because of high soil and water salinities. Nearly 20% of the original 15,000-square-kilometer marsh area was reflooded by March 2004, but the extent of marsh restoration is unknown. High-quality water, nonsaline soils, and the densest native vegetation were found in the only remaining natural marsh, the Al-Hawizeh, located on the Iranian border. Although substantially reduced in area and under current threat of an Iranian dike, it has the potential to be a native repopulation center for the region. Rapid reestablishment, high productivity, and reproduction of native flora and fauna in reflooded former marsh areas indicate a high probability for successful restoration, provided the restored wetlands are hydraulically designed to allow sufficient flow of noncontaminated water and flushing of salts through the ecosystem.
Genotypic Diversity Within a Natural Coastal Bacterioplankton Population
Authors: Thompson Janelle R. , Pacocha Sarah , Pharino Chanathip , Klepac-Ceraj Vanja , Hunt Dana E. , Benoit Jennifer , Sarma-Rupavtarm Ramahi , Distel Daniel L. , Polz Martin F.
Published: February 2005

The genomic diversity and relative importance of distinct genotypes within natural bacterial populations have remained largely unknown. Here, we analyze the diversity and annual dynamics of a group of coastal bacterioplankton (greater than 99% 16
S
ribosomal RNA identity to
Vibrio splendidus
). We show that this group consists of at least a thousand distinct genotypes, each occurring at extremely low environmental concentrations (on average less than one cell per milliliter). Overall, the genomes show extensive allelic diversity and size variation. Individual genotypes rarely recurred in samples, and allelic distribution did not show spatial or temporal substructure. Ecological considerations suggest that much genotypic and possibly phenotypic variation within natural populations should be considered neutral.
Cassini Magnetometer Observations During Saturn Orbit Insertion
Authors: Dougherty M. K. , Achilleos N. , Andre N. , Arridge C. S. , Balogh A. , Bertucci C. , Burton M. E. , Cowley S. W. H. , Erdos G. , Giampieri G. , Glassmeier K.-H. , Khurana K. K. , Leisner J. , Neubauer F. M. , Russell C. T. , Smith E. J. , Southwood D. J. , Tsurutani B. T.
Published: February 2005

Cassini's successful orbit insertion has provided the first examination of Saturn's magnetosphere in 23 years, revealing a dynamic plasma and magnetic environment on short and long time scales. There has been no noticeable change in the internal magnetic field, either in its strength or its near-alignment with the rotation axis. However, the external magnetic field is different compared with past spacecraft observations. The current sheet within the magnetosphere is thinner and more extended, and we observed small diamagnetic cavities and ion cyclotron waves of types that were not reported before.
Bacterial Injectisomes: Needle Length Does Matter
Authors: Mota Luís Jaime , Journet Laure , Sorg Isabel , Agrain Céline , Cornelis Guy R.
Published: February 2005

Many pathogenic bacteria use a type III secretion nanomachine (an injectisome) to deliver virulence proteins into the cytosol of their eukaryotic host cells. Most injectisomes possess a stiff needlelike structure of a genetically defined length. We found that a minimal needle length was required for efficient functioning of the
Yersinia enterocolitica
injectisome. This minimal needle length correlated with the length of the major adhesin at the bacterial surface. The needle may be required for triggering type III secretion, and its length may have evolved to match specific structures at the bacterial and host cell surfaces.
The Use of Transit Timing to Detect Terrestrial-Mass Extrasolar Planets
Authors: Holman Matthew J. , Murray Norman W.
Published: February 2005

Future surveys for transiting extrasolar planets are expected to detect hundreds of jovian-mass planets and tens of terrestrial-mass planets. For many of these newly discovered planets, the intervals between successive transits will be measured with an accuracy of 0.1 to 100 minutes. We show that these timing measurements will allow for the detection of additional planets in the system (not necessarily transiting) by their gravitational interaction with the transiting planet. The transit-time variations depend on the mass of the additional planet, and in some cases terrestrial-mass planets will produce a measurable effect. In systems where two planets are seen to transit, the density of both planets can be determined without radial-velocity observations.
Cassini Imaging Science: Initial Results on Phoebe and Iapetus
Authors: Porco C. C. , Baker E. , Barbara J. , Beurle K. , Brahic A. , Burns J. A. , Charnoz S. , Cooper N. , Dawson D. D. , Del Genio A. D. , Denk T. , Dones L. , Dyudina U. , Evans M. W. , Giese B. , Grazier K. , Helfenstein P. , Ingersoll A. P. , Jacobson R. A. , Johnson T. V. , McEwen A. , Murray C. D. , Neukum G. , Owen W. M. , Perry J. , Roatsch T. , Spitale J. , Squyres S. , Thomas P. C. , Tiscareno M. , Turtle E. , Vasavada A. R. , Veverka J. , Wagner R. , West R.
Published: February 2005

The Cassini Imaging Science Subsystem acquired high-resolution imaging data on the outer Saturnian moon, Phoebe, during Cassini's close flyby on 11 June 2004 and on Iapetus during a flyby on 31 December 2004. Phoebe has a heavily cratered and ancient surface, shows evidence of ice near the surface, has distinct layering of different materials, and has a mean density that is indicative of an ice-rock mixture. Iapetus's dark leading side (Cassini Regio) is ancient, heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief. Local albedo variations within and bordering Cassini Regio suggest mass wasting of ballistically deposited material, the origin of which remains unknown.
Courting Disaster
Authors: Foster Kenneth R.
Published: February 2005

Catastrophe
Risk and Response.
By Richard A. Posner
. Oxford University Press, New York, 2004. 332 pp. $28, £16.99. ISBN 0-19-517813-0.

Discussing a series of possible catastrophes, natural and human-caused, the author considers what we ought to worry about, what we can dismiss, and how we might consider reducing the most dangerous risks.
Identification of Vaccine Candidate Peptides in the NcSRS2 Surface Protein ofNeospora caninumby Using CD4+Cytotoxic T Lymphocytes and Gamma Interferon-Secreting T Lymphocytes of Infected Holstein Cattle
Authors: Staska Lauren M. , Davies Christopher J. , Brown Wendy C. , McGuire Travis C. , Suarez Carlos E. , Park Joo Youn , Mathison Bruce A. , Abbott Jeffrey R. , Baszler Timothy V.
Published: February 2005

Previously, our laboratory showed that Holstein cattle experimentally infected withNeospora caninumdevelop parasite-specific CD4+cytotoxic T lymphocytes (CTL) that lyse infected, autologous target cells through a perforin-granzyme pathway. To identify specific parasite antigens inducing bovine CTL and helper T-lymphocyte responses for vaccine development against bovine neosporosis, the tachyzoite major surface proteins NcSAG1 and NcSRS2 were targeted. In whole tachyzoite antigen-expanded bovine T-lymphocyte lines, recombinant NcSRS2 induced potent memory CD4+- and CD8+-T-lymphocyte activation, as indicated by proliferation and gamma interferon (IFN-γ) secretion, while recombinant NcSAG1 induced a minimal memory response. Subsequently, T-lymphocyte epitope-bearing peptides of NcSRS2 were mapped by using overlapping peptides covering the entire NcSRS2 sequence. Four experimentally infected cattle with six different major histocompatibility complex (MHC) class II haplotypes were the source of immune cells used to identify NcSRS2 peptides presented by Holstein MHC haplotypes. NcSRS2 peptides were mapped by using IFN-γ secretion by rNcSRS2-stimulated, short-term T-lymphocyte cell lines, IFN-γ enzyme-linked immunospot (ELISPOT) assay with peripheral blood mononuclear cells, and51Cr release cytotoxicity assay of rNcSRS2-stimulated effector cells. FourN. caninum-infected Holstein cattle developed NcSRS2 peptide-specific T lymphocytes detected ex vivo in peripheral blood by IFN-γ ELISPOT and in vitro by measuring T-lymphocyte IFN-γ production and cytotoxicity. An immunodominant region of NcSRS2 spanning amino acids 133 to 155 was recognized by CD4+T lymphocytes from the four cattle. These findings support investigation of subunitN. caninumvaccines incorporating NcSRS2 gene sequences or peptides for induction of NcSRS2 peptide-specific CTL and IFN-γ-secreting T lymphocytes in cattle with varied MHC genotypes.
Mucosal Adjuvant Properties of Mutant LT-IIa and LT-IIb Enterotoxins That Exhibit Altered Ganglioside-Binding Activities
Authors: Nawar Hesham F. , Arce Sergio , Russell Michael W. , Connell Terry D.
Published: February 2005

LT-IIa and LT-IIb, the type II heat-labile enterotoxins ofEscherichia coli, are closely related in structure and function to cholera toxin and LT-I, the type I heat-labile enterotoxins ofVibrio choleraeandE. coli, respectively. Recent studies from our group demonstrated that LT-IIa and LT-IIb are potent systemic and mucosal adjuvants. To determine whether binding of LT-IIa and LT-IIb to their specific ganglioside receptors is essential for adjuvant activity, LT-IIa and LT-IIb enterotoxins were compared with their respective single-point substitution mutants which have no detectable binding activity for their major ganglioside receptors [e.g., LT-IIa(T34I) and LT-IIb(T13I)]. Both mutant enterotoxins exhibited an extremely low capacity for intoxicating mouse Y1 adrenal cells and for inducing production of cyclic AMP in a macrophage cell line. BALB/c female mice were immunized by the intranasal route with the surface adhesin protein AgI/II ofStreptococcus mutansalone or in combination with LT-IIa, LT-IIa(T34I), LT-IIb, or LT-IIb(T13I). Both LT-IIa and LT-IIb potentiated strong mucosal and systemic immune responses against AgI/II. Of the two mutant enterotoxins, only LT-IIb(T13I) had the capacity to strongly potentiate mucosal anti-AgI/II and systemic anti-AgI/II antibody responses. Upon boosting with AgI/II, however, both LT-IIa(T34I) and LT-IIb(T13I) enhanced humoral memory responses to AgI/II. Flow cytometry demonstrated that LT-IIa(T34I) had no affinity for cervical lymph node lymphocytes. In contrast, LT-IIb(T13I) retained binding activity for T cells, B cells, and macrophages, indicating that this immunostimulatory mutant enterotoxin interacts with one or more unknown lymphoid cell receptors.
The
fimYZ
Genes Regulate
Salmonella enterica
Serovar Typhimurium Invasion in Addition to Type 1 Fimbrial Expression and Bacterial Motility
Authors: Baxter M. Aaron , Jones Bradley D.
Published: February 2005

An important step in
Salmonella enterica
serovar Typhimurium virulence is the ability to invade the intestinal epithelium. The invasion process requires a large number of genes encoded on
Salmonella
pathogenicity island 1 (SPI-1) at centisome 63 as well as genes located in other positions throughout the chromosome. Expression of the invasive phenotype is tightly regulated by environmental cues that are processed by a complex regulatory scheme. A central player in the invasion regulatory pathway is the HilA protein, which is transcriptional activator belonging to the OmpR/ToxR family. A number of positive regulators (
hilC
,
hilD
,
fis
,
sirA
/
barA
,
csrAB
,
phoBR
,
fadD
,
envZ
/
ompR
, and
fliZ
) and negative regulators (
hha
,
hilE
,
lon
,
ams
,
phoP

c

and
pag
) have been identified that are able to alter expression of
hilA
transcription. Recent work has found that
hilA
transcription requires the HilD protein for activation. Other work has emphasized the importance of HilE as a negative regulator of
hilA
. Overexpression of
hilE
superrepresses
hilA
transcription, as well as the invasive phenotype. Two-hybrid experiments suggest that HilE exerts its regulatory influence on
hilA
through protein-protein interactions with HilD as the protein does not bind to the
hilA
promoter nor does it affect
hilD
transcription. As it seems likely that
hilE
plays an important role in translating environmental signals into invasion gene regulation, we have attempted to identify how the
hilE
gene itself is regulated. Our results indicate that the
fimYZ
genes, response regulatory proteins involved in type 1 fimbrial gene expression and recently implicated in motility gene regulation, are important activators of
hilE
expression. These findings indicate that invasion gene expression is coregulated with motility and adherence and provide experimental evidence that the expression of these virulence phenotypes is a subset of the overall regulation of bacterial physiology.
Functional Implication of the Hydrolysis of Platelet Endothelial Cell Adhesion Molecule 1 (CD31) by Gingipains ofPorphyromonas gingivalisfor the Pathology of Periodontal Disease
Authors: Yun Peter L. W. , Decarlo Arthur A. , Chapple Cheryl C. , Hunter Neil
Published: February 2005

Periodontitis is a response of highly vascularized tissues to the adjacent microflora of dental plaque. Progressive disease has been related to consortia of anaerobic bacteria, with the gram-negative organismPorphyromonas gingivalisparticularly implicated. The gingipains, comprising a group of cysteine proteinases and associated hemagglutinin domains, are major virulence determinants of this organism. As vascular expression of leukocyte adhesion molecules is a critical determinant of tissue response to microbial challenge, the objective of this study was to determine the capacity of gingipains to modulate the expression and function of these receptors. Given the potential multifunctional role of platelet endothelial cell adhesion molecule 1 (PECAM-1) in the vasculature, the effect of gingipains on PECAM-1 expression by endothelial cells was examined. Activated gingipains preferentially down-regulated PECAM-1 expression on endothelial cells compared with vascular cell adhesion molecule 1 and endothelial-leukocyte adhesion molecule 1, but the reduction in PECAM-1 expression was completely inhibited in the presence of the cysteine proteinase inhibitor TLCK (Nα-p-tosyl-l-lysine chloromethyl ketone). Endothelial monolayers treated with activated gingipains demonstrated progressive intercellular gap formation that correlated with reduced intercellular junctional PECAM-1 expression as determined by Western blotting and immunofluorescence microscopy. This was accompanied by enhanced transfer of both albumin and neutrophils across the monolayer. The results suggest that degradation of PECAM-1 by gingipains contributes to increased vascular permeability and neutrophil flux at disease sites.
Broad Degradation of Proapoptotic Proteins with the Conserved Bcl-2 Homology Domain 3 during Infection with
Chlamydia trachomatis
Authors: Ying Songmin , Seiffert Barbara M. , Häcker Georg , Fischer Silke F.
Published: February 2005

Chlamydiae are obligate intracellular bacteria that can inhibit apoptosis of their host cell. As shown recently, this inhibition is in part explained by the proteolytic degradation of the proapoptotic Bcl-2 family members (BH3-only proteins) Bim, Puma, and Bad upon chlamydial infection. In this study, we further explore this antiapoptotic mechanism. In cells infected with a
Chlamydia trachomatis
L2 strain, Bim, Puma, and Bad were degraded with similar kinetics, and the degradation of all three was blocked by inhibition of the proteasome. Furthermore, the BH3-only proteins Bmf, Noxa, and tBid were also targeted by chlamydial infection. The constitutively expressed Bmf disappeared during infection. When Noxa was experimentally induced, the levels were also reduced by infection with
C. trachomatis
. In death-receptor-induced apoptosis, cleaved and activated tBid was degraded, and this destruction was also prevented by inhibition of the proteasome. These results show that chlamydial infection leads to a broad degradation of BH3-only proteins. This loss of proapoptotic factors can explain the almost general protection of infected cells against apoptotic stimuli.
A
Vibrio vulnificus
Type IV Pilin Contributes to Biofilm Formation, Adherence to Epithelial Cells, and Virulence
Authors: Paranjpye Rohinee N. , Strom Mark S.
Published: February 2005

Vibrio vulnificus
expresses a multitude of cell-associated and secreted factors that potentially contribute to pathogenicity, although the specific roles of most of these factors have been difficult to define. Previously we have shown that a mutation in
pilD
(originally designated
vvpD
), which encodes a type IV prepilin peptidase/
N
-methyltransferase, abolishes expression of surface pili, suggesting that they belong to the type IV class. In addition, a
pilD
mutant exhibits reduced adherence to HEp-2 cells, a block in secretion of several exoenzymes that follow the type II secretion pathway, and decreased virulence. In this study, we have cloned and characterized a
V. vulnificus
type IV pilin (PilA) that shares extensive homology to group A type IV pilins expressed by many pathogens, including
Vibrio cholerae
(PilA),
Pseudomonas aeruginosa
(PilA), and
Aeromonas hydrophila
(TapA). The
V. vulnificus pilA
gene is part of an operon and is clustered with three other pilus biogenesis genes,
pilBCD
. Inactivation of
pilA
reduces the ability of
V. vulnificus
to form biofilms and significantly decreases adherence to HEp-2 cells and virulence in iron dextran-treated mice. Southern blot analysis demonstrates the widespread presence of both
pilA
and
pilD
in clinical as well as environmental strains of
V. vulnificus
.
Staphylococcus aureus
Capsular Polysaccharide Types 5 and 8 Reduce Killing by Bovine Neutrophils In Vitro
Authors: Kampen Annette H. , Tollersrud Tore , Lund Arve
Published: February 2005

Isogenic variants of
Staphylococcus aureus
strain Reynolds expressing either no capsule or capsular polysaccharide (CP) type 5 (CP5) or type 8 (CP8) were used to assess the effect of CP on bacterial killing and the respiratory burst of bovine neutrophils. The effects of antisera specific for CP5 and CP8 were also evaluated. The killing of live bacteria by isolated neutrophils was quantified in a bactericidal assay, while the respiratory burst after stimulation with live bacteria in whole blood was measured by flow cytometry. The expression of a CP5 or CP8 capsule protected the bacteria from being killed by bovine neutrophils in vitro (
P
< 0.001), and the capsule-expressing variants did not stimulate respiratory burst activity in calf whole blood. The addition of serotype-specific antisera increased the killing of the capsule-expressing bacteria and enhanced their stimulating effect in the respiratory burst assay (
P
< 0.01). When the
S. aureus
variants were grown under conditions known not to promote capsule expression, there were no significant differences between them. The present study demonstrates that the expression of
S. aureus
CP5 or CP8 confers resistance to opsonophagocytic killing and prevents the bacteria from inducing respiratory burst of bovine neutrophils in vitro and that these effects can be reversed by the addition of serotype-specific antisera.
Bordetella pertussis-Infected Human Monocyte-Derived Dendritic Cells Undergo Maturation and Induce Th1 Polarization and Interleukin-23 Expression
Authors: Fedele Giorgio , Stefanelli Paola , Spensieri Fabiana , Fazio Cecilia , Mastrantonio Paola , Ausiello Clara M.
Published: February 2005

Bordetella pertussis, the causative agent of whooping cough, is internalized by several cell types, including epithelial cells, monocytes, and neutrophils. Although its ability to survive intracellularly is still debated, it has been proven that cell-mediated immunity (CMI) plays a pivotal role in protection. In this study we aimed to clarify the interaction ofB. pertussiswith human monocyte-derived dendritic cells (MDDC), evaluating the ability of the bacterium to enter MDDC, to survive intracellularly, to interfere with the maturation process and functional activities, and to influence the host immune responses. The results obtained showed thatB. pertussishad a low capability to be internalized by—and to survive in—MDDC. Upon contact with the bacteria, immature MDDC were induced to undergo phenotypic maturation and acquired antigen-presenting-cell functions. Despite the high levels of interleukin-10 (IL-10) and the barely detectable levels of IL-12 induced byB. pertussis, the bacterium induced maturation of MDDC and T helper 1 (Th1) polarized effector cells. Gene expression analysis of the IL-12 cytokine family clearly demonstrated thatB. pertussisinduced high levels of the p40 and p19 subunits of IL-23 yet failed to induce the expression of the p35 subunit of IL-12. Overall our findings show thatB. pertussis, even if it survives only briefly in MDDC, promotes the synthesis of IL-23, a newly discovered Th1 polarizing cytokine. A Th1-oriented immune response is thus allowed, relevant in the induction of an adequate CMI response, and typical of protection induced by natural infection or vaccination with whole-cell vaccines.
Demonstration of Type IV Pilus Expression and a Twitching Phenotype by
Haemophilus influenzae
Authors: Bakaletz Lauren O. , Baker Beth D. , Jurcisek Joseph A. , Harrison Alistair , Novotny Laura A. , Bookwalter James E. , Mungur Rachna , Munson Robert S.
Published: February 2005

Haemophilus influenzae
is considered a nonmotile organism that expresses neither flagella nor type IV pili, although
H. influenzae
strain Rd possesses a cryptic pilus locus. We demonstrate here that the homologous gene cluster
pilABCD
in an otitis media isolate of nontypeable
H. influenzae
strain 86-028NP encodes a surface appendage that is highly similar, structurally and functionally, to the well-characterized subgroup of bacterial pili known as type IV pili. This gene cluster includes a gene (
pilA
) that likely encodes the major subunit of the heretofore uncharacterized
H. influenzae
-expressed type IV pilus, a gene with homology to a type IV prepilin peptidase (
pilD
) as well as two additional uncharacterized genes (
pilB
and
pilC
). A second gene cluster (
comABCDEF
) was also identified by homology to other
pil
or type II secretion system genes. When grown in chemically defined medium at an alkaline pH, strain 86-028NP produces approximately 7-nm-diameter structures that are near polar in location. Importantly, these organisms exhibit twitching motility. A mutation in the
pilA
gene abolishes both expression of the pilus structure and the twitching phenotype, whereas a mutant lacking ComE, a
Pseudomonas
PilQ homologue, produced large appendages that appeared to be membrane bound and terminated in a slightly bulbous tip. These latter structures often showed a regular pattern of areas of constriction and expansion. The recognition that
H. influenzae
possesses a mechanism for twitching motility will likely profoundly influence our understanding of
H. influenzae
-induced diseases of the respiratory tract and their sequelae.
Comparison between
Candida albicans
Agglutinin-Like Sequence Gene Expression Patterns in Human Clinical Specimens and Models of Vaginal Candidiasis
Authors: Cheng Georgina , Wozniak Karen , Wallig Matthew A. , Fidel Paul L. , Trupin Suzanne R. , Hoyer Lois L.
Published: February 2005

Expression of the eight genes in the
Candida albicans
agglutinin-like sequence (ALS) family was studied by reverse transcription-PCR of RNA isolated from clinical vaginal fluid specimens and vaginal candidiasis model systems. Although expression of all ALS genes was detected across the set of clinical specimens,
ALS1
,
ALS2
,
ALS3
, and
ALS9
transcripts were detected most frequently, and expression of
ALS4
and
ALS5
was detected least frequently. Laboratory strain 3153A and two
C. albicans
strains isolated from the clinical specimens were studied using two models of vaginal candidiasis to determine how closely these models mimicked the clinical specimens at the level of gene expression. ALS gene expression patterns in a murine vaginitis model were identical to those from the clinical specimens. Expression of more ALS genes was detected in specimens collected 7 days after infection compared to those collected at 4 days. Similar patterns of ALS gene expression were observed when the three
C. albicans
strains were tested in the reconstituted human vaginal epithelium model. In this model, expression of
ALS4
,
ALS5
,
ALS6
, and
ALS7
was least frequently detected. Negative or weakened signals for
ALS4
expression were observed at early time points, suggesting that
ALS4
expression, which was strong in the inoculum cells, was down-regulated upon contact of
C. albicans
with vaginal epithelial cells in this model. The data presented here support the conclusion of host-site-specific influences on ALS gene expression and validate the use of the experimental models for evaluating the phenotype of
als
/
als
mutant strains.
GastricHelicobacterInfection Induces a Th2 Phenotype but Does Not Elevate Serum Cholesterol in Mice Lacking Inducible Nitric Oxide Synthase
Authors: Ihrig Melanie , Whary Mark T. , Dangler Charles A. , Fox James G.
Published: February 2005

PersistentHelicobacter felisinfection in (C57BL/6 × 129SvEv)F1mice induces chronic gastritis. Expression of inducible nitric oxide synthase (iNOS) is upregulated in response toHelicobacterinfection. In this study, 20 10-week-old iNOS−/−mice and 20 wild-type [(C57BL/6 × 129SvEv)F1] mice were infected withH. felisby oral gavage and were assessed histologically and serologically at 32 weeks postinfection. Equal numbers of uninfected controls were sham inoculated. The mice were scored for severity of gastric inflammation, hyperplasia, glandular atrophy, and mucous metaplasia in the corpus and for the level of helicobacter colonization. The immunoglobulin G1 (IgG1), IgG2a, and IgG2c antibody responses toH. feliswere determined. As a secondary measure, serum cholesterol levels were assessed. iNOS−/−mice have a propensity for increased serum cholesterol, and although controversial, several human epidemiologic studies have demonstrated an association betweenHelicobacterinfection and several risk factors for cardiovascular disease, including elevated serum cholesterol. Nevertheless, no differences in serum cholesterol levels were observed between theH. felis-infected and -uninfected iNOS−/−mice in this study. The uninfected animals had minimal to no gastric pathology. The gastric pathology scores for the infected animals were reduced significantly in the iNOS-deficient mice relative to those for the wild-type mice (allP< 0.01).Helicobacter-infected iNOS−/−mice had chronic lymphoid infiltration and negligible to mild glandular atrophy and mucous metaplasia in the fundic mucosa, whileH. felis-infected wild-type mice had severe atrophic and metaplastic mucosal changes. The atrophic gastritis in the infected wild-type mice, particularly the female mice, was also accompanied by greater granulocytic infiltration, antral hyperplasia, and diminished antral colonization, unlike that in the infected iNOS−/−mice. iNOS−/−mice developed significantly lower Th1-associated IgG2c antibody responses toH. felis(P< 0.0003); the Th2-associated IgG1 responses were similar (P= 0.09), suggesting a greater effect of the iNOS defect on Th1 responses.H. feliscolonization was significantly greater in the iNOS-deficient mice. These findings are indicative of an impaired Th1 component of theH. felis-induced inflammatory response when the influence of iNOS is removed.
HosA, a Member of the SlyA Family, Regulates Motility in Enteropathogenic
Escherichia coli
Authors: Ferrándiz Maria-José , Bishop Keith , Williams Paul , Withers Helen
Published: February 2005

In enteropathogenic and enterohemorraghic
Escherichia coli
(EPEC and EHEC), two members of the SlyA family of transcriptional regulators have been identified as SlyA. Western blot analysis of the wild type and the corresponding
hosA
and
slyA
deletion mutants indicated that SlyA and HosA are distinct proteins whose expression is not interdependent. Of 27 different
E. coli
strains (EPEC, EHEC, enteroinvasive, enteroaggregative, uropathogenic, and commensal) examined, 14 were positive for both genes and proteins. To investigate
hosA
expression, a
hosA
::
luxCDABE
reporter gene fusion was constructed.
hosA
expression was significantly reduced in the
hosA
but not the
slyA
mutant and was influenced by temperature, salt, and pH. In contrast to SlyA, HosA did not activate the cryptic
E. coli
K-12 hemolysin ClyA. Mutation of
hosA
did not influence type III secretion, the regulation of the LEE1 and LEE4 operons, or the ability of E2348/69 to form attaching-and-effacing lesions on intestinal epithelial cells. HosA is, however, involved in the temperature-dependent positive control of motility on swim plates and regulates
fliC
expression and FliC protein levels. In electrophoretic mobility shift assays, purified HosA protein bound specifically to the
fliC
promoter, indicating that HosA directly modulates flagellin expression. While direct examination of flagellar structure and the motile behavior of individual
hosA
cells grown in broth culture at 30°C did not reveal any obvious differences,
hosA
mutants, unlike the wild type, clumped together, forming nonmotile aggregates which could account for the markedly reduced motility of the
hosA
mutant on swim plates at 30°C. We conclude that SlyA and HosA are independent transcriptional regulators that respond to different physicochemical cues to facilitate the environmental adaptation of
E. coli
.
Activities of
Pseudomonas aeruginosa
Effectors Secreted by the Type III Secretion System In Vitro and during Infection
Authors: Lee Vincent T. , Smith Roger S. , Tümmler Burkhard , Lory Stephen
Published: February 2005

Pseudomonas aeruginosa
utilizes a number of distinct pathways to secrete proteins that play various roles during infection. These include the type II secretion system, which is responsible for the secretion of the majority of exoproducts into the surrounding environment, including toxins and degradative enzymes. In contrast, the type III secretion system mediates the delivery of protein effectors directly into the cytoplasm of the host cell. Using tissue culture assays and a mouse acute-pneumonia model, we have determined the contribution of each of the type III effectors during infection. In strain PAK, ExoS is the major cytotoxin required for colonization and dissemination during infection. ExoT confers protection of tissue culture cells from type III-dependent lysis, while ExoY seemed to have little effect on cytotoxicity. ExoU is over 100-fold more cytotoxic than ExoS. The cytotoxicity of type II secretion was determined following deletion of the genes for the more toxic type III secretion system. The participation of these secretion systems during lifelong colonization of cystic fibrosis (CF) patients is unclear. By comparing clonal strains from the same patient isolated at the initial onset of
P. aeruginosa
infection and more than a decade later, after chronic colonization has been established, we show that initial strains are more cytotoxic than chronic strains that have evolved to reduce type III secretion. Constitutive expression of genes for the type III secretion system restored ExoS secretion but did not always reestablish cytotoxicity, suggesting that CF strains accumulate a number of mutations to reduce bacterial toxicity to the host.
Age Alterations in Extent and Severity of Experimental Intranasal Infection withChlamydophila pneumoniaein BALB/c Mice
Authors: Little C. Scott , Bowe Andrew , Lin Richard , Litsky Jason , Fogel Robert M. , Balin Brian J. , Fresa-Dillon Kerin L.
Published: February 2005

The intracellular bacteriumChlamydophila(“Chlamydia”)pneumoniaeis a pathogen for several respiratory diseases and may be a factor in the pathogenesis of chronic diseases of aging including atherosclerosis and Alzheimer's disease. We assessed whether aging is coupled with increased burden of infection in BALB/c mice after intranasal infection byC. pneumoniae. Six- and twenty-month-old BALB/c mice were infected intranasally with 5 × 104inclusion forming units (IFU) or 5 × 105IFU ofC. pneumoniae. Lung, brain, and heart tissue were analyzed for infectiousC. pneumoniaeand forChlamydophilaantigen by immunohistochemistry. At both doses, aging was associated with a decreased proportion of animals that cleared infection from the lung and greater burden of infectious organism within the lung. We observed dose-dependent spread to the heart/ascending aorta in animals infected withC. pneumoniae. In mice given 5 × 104IFU, spread to the heart by day 14 was only observed in old mice. By day 28, all animals inoculated with 5 × 104IFU showed evidence of spread to the heart, although higherC. pneumoniaetiters were observed in the hearts from old mice. In mice inoculated with 5 × 105IFU, spread ofC. pneumoniaeto the heart was evident by day 14, with no discernible age effect.C. pneumoniaewas also recovered from the central nervous system (brain and olfactory bulb) of all mice by day 28 postinfection, with higherC. pneumoniaetiters in old animals than in young animals. Our results suggest that infection withC. pneumoniaemay be more severe in old animals.
Neutrophil Responses toMycobacterium tuberculosisInfection in Genetically Susceptible and Resistant Mice
Authors: Eruslanov Evgenyi B. , Lyadova Irina V. , Kondratieva Tatiana K. , Majorov Konstantin B. , Scheglov Ilya V. , Orlova Marianna O. , Apt Alexander S.
Published: February 2005

The role of neutrophils in tuberculosis (TB) resistance and pathology is poorly understood. Neutrophil reactions are meant to target the offending pathogen but may lead to destruction of the host lung tissue, making the defending cells an enemy. Here, we show that mice of the I/St strain which are genetically susceptible to TB show an unusually high and prolonged neutrophil accumulation in their lungs after intratracheal infection. Compared to neutrophils from more resistant A/Sn mice, I/St neutrophils display an increased mobility and tissue influx, prolonged lifespan, low expression of the CD95 (Fas) apoptotic receptor, relative resistance to apoptosis, and an increased phagocytic capacity for mycobacteria. Segregation genetic analysis in (I/St × A/Sn)F2hybrids indicates that the alleles of I/St origin at the chromosome 3 and 17 quantitative trait loci which are involved in the control of TB severity also determine a high level of neutrophil influx. These features, along with the poor ability of neutrophils to restrict mycobacterial growth compared to that of lung macrophages, indicate that the prevalence of neutrophils in TB inflammation contributes to the development of pathology, rather than protection of the host, and that neutrophils may play the role of a “Trojan horse” for mycobacteria.
Colonization and Inflammation Deficiencies in Mongolian Gerbils Infected byHelicobacter pyloriChemotaxis Mutants
Authors: McGee David J. , Langford Melanie L. , Watson Emily L. , Carter J. Elliot , Chen Yu-Ting , Ottemann Karen M.
Published: February 2005

Helicobacter pyloricauses disease in the human stomach and in mouse and gerbil stomach models. Previous results have shown that motility is critical forH. pylorito colonize mice, gerbils, and other animal models. The role of chemotaxis, however, in colonization and disease is less well understood. Two genes in theH. pylorichemotaxis pathway,cheYandtlpB, which encode the chemotaxis response regulator and a methyl-accepting chemoreceptor, respectively, were disrupted. ThecheYmutation was complemented with a wild-type copy ofcheYinserted into the chromosomalrdxAgene. ThecheYmutant lost chemotaxis but retained motility, while all other strains were motile and chemotactic in vitro. These strains were inoculated into gerbils either alone or in combination with the wild-type strain, and colonization and inflammation were assessed. While thecheYmutant completely failed to colonize gerbil stomachs, thetlpBmutant colonized at levels similar to those of the wild type. With thetlpBmutant, there was a substantial decrease in inflammation in the gerbil stomach compared to that with the wild type. Furthermore, there were differences in the numbers of each immune cell in thetlpB-mutant-infected stomach: the ratio of lymphocytes to neutrophils was about 8 to 1 in the wild type but only about 1 to 1 in the mutant. These results suggest that the TlpB chemoreceptor plays an important role in the inflammatory response while the CheY chemotaxis regulator plays a critical role in initial colonization. Chemotaxis mutants may provide new insights into the steps involved inH. pyloripathogenesis.
Profile of
Candida albicans-
Secreted Aspartic Proteinase Elicited during Vaginal Infection
Authors: Taylor Brad N. , Staib Peter , Binder Ayfer , Biesemeier Antje , Sehnal Miriam , Röllinghoff Martin , Morschhäuser Joachim , Schröppel Klaus
Published: February 2005

Vaginal infections caused by the opportunistic yeast
Candida albicans
are a significant problem in women of child-bearing age. Several factors are recognized as playing a crucial role in the pathogenesis of superficial candidiasis; these factors include hyphal formation, phenotypic switching, and the expression of virulence factors, including a 10-member family of secreted aspartic proteinases. In the present investigation, we analyzed the secreted aspartic proteinase gene (
SAP
) expression profile of
C. albicans
that is elicited in the course of vaginal infection in mice and how this in vivo expression profile is associated with hyphal formation. We utilized two different genetic reporter systems that allowed us to observe
SAP
expression on a single-cell basis, a recombination-based in vivo expression technology and green fluorescent protein-expressing
Candida
reporter strains. Of the six
SAP
genes that were analyzed (
SAP1
to
SAP6
), only
SAP4
and
SAP5
were detectably induced during infection in this model. Expression of both of these genes was associated with hyphal growth, although not all hyphal cells detectably expressed
SAP4
and
SAP5. SAP5
expression was induced soon after infection, whereas
SAP4
was expressed at later times and in fewer cells compared with
SAP5
. These findings point to a link between morphogenetic development and expression of virulence genes during
Candida
vaginitis in mice, where host signals induce both hyphal formation and expression of
SAP4
and
SAP5
, but temporal gene expression patterns are ultimately controlled by other factors.
Factors Characterizing
Staphylococcus epidermidis
Invasiveness Determined by Comparative Genomics
Authors: Yao Yufeng , Sturdevant Daniel E. , Villaruz Amer , Xu Lin , Gao Qian , Otto Michael
Published: February 2005

Virulence mechanisms of the leading nosocomial pathogen
Staphylococcus epidermidis
are poorly understood. We used microarray-based genome-wide comparison of clinical and commensal
S. epidermidis
strains to identify putative virulence determinants. Our study revealed high genetic variability of the
S. epidermidis
genome, new markers for invasiveness of
S. epidermidis
, and potential targets for drug development against
S. epidermidis
infections.
Sublethal Infection of C57BL/6 Mice with
Salmonella enterica
Serovar Typhimurium Leads to an Increase in Levels of Toll-Like Receptor 1 (TLR1), TLR2, and TLR9 mRNA as Well as a Decrease in Levels of TLR6 mRNA in Infected Organs
Authors: Tötemeyer Sabine , Kaiser Pete , Maskell Duncan J. , Bryant Clare E.
Published: February 2005

Sublethal infection of C57BL/6 mice with
Salmonella enterica
serovar Typhimurium M525P initiates a strong inflammatory response. We measured organ expression of mRNA for Toll-like receptors and their associated signaling molecules during
S. enterica
serovar Typhimurium infection. During infection, the Toll-lie receptor 1 (TLR1), TLR2, and TLR9 mRNA levels increased, while TLR6 mRNA expression decreased.
GeneChip Analyses of Global Transcriptional Responses of Murine Macrophages to the Lethal Toxin ofBacillus anthracis
Authors: Comer Jason E. , Galindo Cristi L. , Chopra Ashok K. , Peterson Johnny W.
Published: February 2005

We performed GeneChip analyses on RNA fromBacillus anthracislethal toxin (LeTx)-treated RAW 264.7 murine macrophages to investigate global effects of anthrax toxin on host cell gene expression. Stringent analysis of data revealed that the expression of several mitogen-activated protein kinase kinase-regulatory genes was affected within 1.5 h post-exposure to LeTx. By 3.0 h, the expression of 103 genes was altered, including those involved in intracellular signaling, energy production, and protein metabolism.
Mycobacterium tuberculosis
with Disruption in Genes Encoding the Phosphate Binding Proteins PstS1 and PstS2 Is Deficient in Phosphate Uptake and Demonstrates Reduced In Vivo Virulence
Authors: Peirs Priska , Lefèvre Philippe , Boarbi Samira , Wang Xiao-Ming , Denis Olivier , Braibant Martine , Pethe Kevin , Locht Camille , Huygen Kris , Content Jean
Published: February 2005

By measuring phosphate uptake by
Mycobacterium tuberculosis
strains with the
pstS1
and
pstS2
genes genetically inactivated, we showed that these
pstS
genes encode high-affinity phosphate binding proteins. In a mouse infection model, both mutants were attenuated in virulence, suggesting that
M. tuberculosis
encounters limiting phosphate concentrations during its intracellular life span.
Mice Fed Lipid-Encapsulated
Mycobacterium bovis
BCG Are Protected against Aerosol Challenge with
Mycobacterium tuberculosis
Authors: Aldwell Frank E. , Brandt Lise , Fitzpatrick Clare , Orme Ian M.
Published: February 2005

Mice that consumed a single dose of 10
7
lipid-encapsulated
Mycobacterium bovis
BCG bacilli showed significant pulmonary and systemic protection against aerosol challenge with
M. tuberculosis
H37Rv. As an extension of previous challenge studies with virulent strains of
M. bovis
, this report describes a reduction in
M. tuberculosis
infection in mice vaccinated orally with lipid-encapculated BCG comparable to that observed in mice vaccinated subcutaneously with BCG. These results are consistent with the induction of tuberculin-specific cell-mediated immune responses.