Effective methods for teaching patient-centred interviewing skills are resource intensive. Providing students the opportunity to work in small groups with simulated patients is highly valued and has demonstrable long-term benefits. Expanding cohorts of medical students and diminishing faculty resources led to the implementation of a peer assisted learning (PAL) project in patient-centred interviewing skills. The paper reports the evaluation of a PAL project on student tutors. The methodology included direct and indirect measures of student tutors' skills in facilitation and patient-centred interviewing. The self-report evaluations strongly suggest that participating in a PAL project has substantial benefits for student tutors that included both interviewing and facilitation skills. Objective measures revealed no change in patient-centred interviewing skills after participating in the project. The study concludes that formalizing PAL may tap a valuable resource within the medical school and provide benefits for student tutors. Careful consideration needs to be given to ways in which student tutors are supported before, during and after the project.

The repeatability and efficiency of a corner detector determines how likely it is to be useful in a real-world application. The repeatability is important because the same scene viewed from different positions should yield features which correspond to the same real-world 3D locations. The efficiency is important because this determines whether the detector combined with further processing can operate at frame rate. Three advances are described in this paper. First, we present a new heuristic for feature detection and, using machine learning, we derive a feature detector from this which can fully process live PAL video using less than 5 percent of the available processing time. By comparison, most other detectors cannot even operate at frame rate (Harris detector 115 percent, SIFT 195 percent). Second, we generalize the detector, allowing it to be optimized for repeatability, with little loss of efficiency. Third, we carry out a rigorous comparison of corner detectors based on the above repeatability criterion applied to 3D scenes. We show that, despite being principally constructed for speed, on these stringent tests, our heuristic detector significantly outperforms existing feature detectors. Finally, the comparison demonstrates that using machine learning produces significant improvements in repeatability, yielding a detector that is both very fast and of very high quality.

Many neuropeptides and peptide hormones require amidation of their carboxy terminal for full biological activity. The enzyme peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL; EC 4.3.2.5) catalyzes the second and last step of this reaction, N-dealkylation of the peptidyl-alpha-hydroxyglycine to generate the alpha-amidated peptide and glyoxylate. Here we report the X-ray crystal structure of the PAL catalytic core (PALcc) alone and in complex with the nonpeptidic substrate alpha-hydroxyhippuric acid. The structures show that PAL folds as a six-bladed beta-propeller. The active site is formed by a Zn(II) ion coordinated by three histidine residues; the substrate binds to this site with its alpha-hydroxyl group coordinated to the Zn(II) ion. The structures also reveal a tyrosine residue (Tyr(654)) at the active site as the catalytic base for hydroxyl deprotonation, an unusual role for tyrosine. A reaction mechanism is proposed based on this structural data and validated by biochemical analysis of site-directed PALcc mutants.

Constitutive over-expression of antifungal genes from microorganisms involved in plant defence mechanisms represents a promising strategy for conferring genetic resistance against a broad range of plant pathogenic fungi. In the present work, two transgenic lemon clones with the chit42 gene from Trichoderma harzianum were tested for resistance to fungal disease and expression level of defence-related genes was evaluated. Different resistance-related processes, such as production of reactive oxygen species (ROS), systemic acquired resistance (SAR) and induced systemic resistance (ISR), were monitored in transgenic and wild type lemon clones inoculated with Botrytis cinerea, the causal agent of grey mould in citrus. Expression of genes that encode gluthatione peroxidase (GPX), a producer of ROS, chitinases, glucanases (SAR), PAL, HPL, and AOS (ISR) was measured by quantitative PCR during the first 24 h after leaf inoculation. Leaves of transgenic lemon plants inoculated with B. cinerea showed significantly less lesion development than wild type leaves. Tissues from detached leaves of different transgenic lemon clones showed a significant correlation between resistance and transgene expression. On the other hand, the over-expression of the transgenic fungal gene enhanced by two-three folds transcript levels of genes associated with enhanced ROS production and ISR establishment, while the expression of native chitinase and glucanase genes involved in SAR was down-regulated.

Phenylalanine ammonia-lyase (PAL) is an important enzyme in both plant development and pathogen defense. In all plants it is encoded by a multi-gene family, ranging in copy number from four in Arabidopsis to a dozen or more copies in some higher plants. Many studies indicate that alternate genes are differentially regulated in response to environmental stimuli. In this study, Southern blot and dot blot analyses in tomato indicate a surprisingly large family of related sequences with approximately 26 copies in the diploid genome, some easily distinguished by restriction enzyme digestion. Analyses of a BAC genome library suggest that the genes are generally not clustered. A more detailed comparison of the gene sequences using PCR to isolate the individual copies and reverse transcription-PCR to study the transcripts that they encode indicates a significant diversity in the gene sequences themselves, but surprisingly only one mRNA transcript can be detected even when additional expression is induced by pathogen growth or wounding. Consistent with previous reports in other plants, a parallel study with a closely related plant, the potato, indicates a much broader utilization of the PAL genes, highlighting the unusual nature of this family in tomato and of the mechanism(s) that silences so many members. Plant transformation analyses further demonstrate the presence of very active silencing, suggesting aggressive competition between PAL gene duplication and copy inactivation during PAL gene evolution.

l-Phenylalanine ammonia-lyase (PAL) activity is low in the external layers (flavedo) of intact mature grapefruit peel. Flavedo discs evince upon incubation increasing PAL activity and ethylene production. Light has no effect in enhancing PAL activity in discs. Exogenous ethylene stimulates PAL activity in the flavedo of intact mature grapefruits (half maximum stimulation at 15 ppm); such activity rapidly decreases when fruit is removed from the ethylene containing atmosphere. Carbon dioxide inhibits both ethylene production and PAL activity of discs; exogenous ethylene only partly relieves PAL inhibition. Cycloheximide inhibits both PAL activity and ethylene production by flavedo discs. The same concentration of cycloheximide also inhibits PAL activity of discs in the presence of exogenous ethylene. Protein synthesis seems therefore to be needed at both levels of ethylene evolution and enhancement of PAL activity.

BACKGROUND

Peak atrial longitudinal strain (PALS) during the reservoir phase has been proposed as a measure of left atrium function in a range of cardiac conditions, with the potential for added pathophysiological insight and prognostic value. However, no studies have assessed the interrelation of PALS and left ventricular longitudinal strain (global longitudinal strain) in large-scale populations in regard to prognosis.

RESULTS

We prospectively included 843 patients (mean age 62.1±11.8; 74% male) with acute myocardial infarction and measured global longitudinal strain, left atrium volumes, and PALS within 48 hours of admission. PALS was related to a composite outcome of death and heart failure hospitalization. Reduced PALS was associated with hypertension, diabetes mellitus, and Killip class >1 (P<0.05 for all). Reduced PALS was associated with impairment of all measures of left ventricular systolic and diastolic function, and the correlation between global longitudinal strain and PALS was highly significant (P<0.001; r=-0.71). During follow-up (median 23.0 months Q1-Q3, 16.8-26.0), a total of 76 patients (9.0%) reached the composite end point of which 47 patients died (5.6%), and 29 patients were hospitalized for heart failure (3.4%). PALS was significantly associated with outcome (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.85-0.90; P<0.001); however, no independent effect of PALS (HR, 1.00; 95% CI, 0.94-1.05; P=0.87) was found when adjusting for global longitudinal strain (HR, 1.20; 95% CI, 1.09-1.33; P<0.001), maximum left atrium volume before mitral valve opening (HR, 1.02; 95% CI, 1.01-1.04; P=0.006), and age (HR, 1.06; 95% CI, 1.03-1.08; P<0.001).

CONCLUSIONS

PALS provides a composite measure of left ventricular longitudinal systolic function and maximum left atrium volume before mitral valve opening, and as such contains no added information when these readily obtained measures are known.

Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) and tyrosine ammonia-lyase (TAL, 4.3.1.), the key enzymes of the phenylpropanoid pathway, are inducible in response to biotic (such as chitin from fungal cell walls) and abiotic cues. Application of chitin and chitosan to soybean leaf tissues caused increased activity of PAL and TAL enzymes. The elevation of enzyme activity was dependent on the chain length of the oligomers and time after treatment. The hexamer of chitin and pentamer of chitosan produced the maximum activities at 36 h after treatment as compared to controls. Total phenolic content of soybean leaves increased following chitosan and chitin oligomer treatments, showing a positive correlation between enzyme activity and total phenolic content.

Miscanthus, a potential energy crop grass, can be damaged by late frost when shoots emerge too early in the spring and during the first winter after planting. The effects of cold acclimation on cell wall composition were investigated in a frost-sensitive clone of Miscanthus x giganteus compared to frost-tolerant clone, Miscanthus sinensis August Feder, and an intermediate frost-tolerant clone, M. sinensis Goliath. Cellulose and lignin contents were higher in M. x giganteus than in the M. sinensis genotypes. In ambient temperature controls, each clone displayed different glucuronoarabinoxylan (GAX) contents and degree of arabinose substitution on the xylan backbone. During cold acclimation, an increase in (1→3),(1→4)-β-D-glucan content was observed in all genotypes. Uronic acid level increased in the frost sensitive genotype but decreased in the frost tolerant genotypes in response to cold. In all clones, major changes in cell wall composition were observed with modifications in phenylalanine ammonia-lyase (PAL) and cinnamyl alcohol dehydrogenase (CAD) activities in both non- and cold-acclimated experiments. A large increase in CAD activity under cold stress was displayed in each clone, but it was largest in the frost-tolerant clone, M. sinensis August Feder. The marked increase in PAL activity observed in the frost-tolerant clones under cold acclimation, suggests a reorientation of the products towards the phenylpropanoid pathway or aromatic synthesis. How changes in cell wall physical properties can impact frost tolerance is discussed.

OBJECTIVE

To investigate the association between keratinized mucosa (KM) width and mucosal thickness (MTh) with clinical and immunological parameters around dental implants.

METHODS

Sixty-three functioning dental implants (3I osseotite) were examined. Clinical examinations included plaque index (PI), probing depth (PD), bleeding on probing (BOP), KM width, MTh and buccal mucosal recession (MR). Peri-implant crevicular fluid (PICF) samples were collected for PgE2 assay.

RESULTS

KM width ranged from 0 to 7 mm (mean 2.5+/-2), MTh ranged from 0.38 to 2.46 mm (mean 1.11+/-0.4) and the mean MR was 0.62 mm, ranging from 0 to 3 mm. A negative correlation was found between MTh and MR (r=-0.32, P=0.01); Likewise, KM width showed a negative correlation with MR, periodontal attachment level (<em>PAL</em>) and PgE2 levels (r=-0.41, P<0.001; r=-0.26, P=0.04; r=-0.26, P=0.04, respectively). In contrast, a positive correlation was found between KM width and PD (r=0.27, P=0.03). When data were dichotomized by KM width, a wider mucosal band (>1 mm) was associated with less MR compared with narrow (<or=1 mm) band (0.27 and 0.9 mm, respectively, P=0.001). A wider KM band was also associated with a greater PD (3.13 mm) compared with a narrow band (2.66 mm, P=0.04). Similarly, a thick mucosa >>or=1 mm) was associated with lesser recession compared with a thin (<1 mm) mucosa (0.45 and 0.9 mm, respectively, P=0.04).

CONCLUSIONS

The KM around dental implants affects both the clinical and the immunological parameters at these sites. These findings are of special importance in the esthetic zone, where thin and narrow KM may lead to a greater MR.

It has been suggested that salicylic acid (SA) is a signal in acquired resistance to pathogens in several plants. Also, it has been suggested that infestation of plants causes an increase in the activity of phenylalanine ammonia-lyase (PAL), a key phenolic biosynthesis enzyme. The purpose of this work was to investigate whether the induction of SA and PAL activity is related to the susceptibility of barley to aphid infestation. The induction of free and conjugated SA in two barley cultivars that differ in susceptibility to aphids was analyzed. Analyses of several physiological parameters showed that cv. UNA-80 was more susceptible to the aphid Schizaphis graminum than cv. LM-109. Salicylic acid was not detected in noninfested plants. Levels of free and conjugated SA in cv. LM-109 and of conjugated SA in cv. UNA-80 increased with aphid infestation, whereas the levels of free SA in cv. UNA-80 remained high under all infestation degrees. Maximum values reached in both cultivars were not significantly different. With respect to PAL activity, cv. LM-109 showed a significantly higher specific activity than cv. UNA-80, the more susceptible cultivar. The relationship between the susceptibility of a plant to aphid and SA induction and PAL activity is discussed.

The moss Physcomitrella patens (P. patens) is a useful model to study abiotic stress responses since it is highly tolerant to drought, salt and osmotic stress. However, very little is known about the defense mechanisms activated in this moss after pathogen assault. In this study, we show that P. patens activated multiple and similar responses against Pythium irregulare and Pythium debaryanum, including the reinforcement of the cell wall, induction of the defense genes CHS, LOX and PAL, and accumulation of the signaling molecules jasmonic acid (JA) and its precursor 12-oxo-phytodienoic acid (OPDA). However, theses responses were not sufficient and infection could not be prevented leading to hyphae colonization of moss tissues and plant decay. Pythium infection induced reactive oxygen species production and caused cell death of moss tissues. Taken together, these data indicate that Pythium infection activates in P. patens common responses to those previously characterized in flowering plants. Microscopic analysis also revealed intracellular relocation of chloroplasts in Pythium-infected tissues toward the infection site. In addition, OPDA, JA and its methyl ester methyl jasmonate induced the expression of PAL. Our results show for the first time JA and OPDA accumulation in a moss and suggest that this defense pathway is functional and has been maintained during the evolution of plants.

Leaves of a novel strain of peas (Pisum sativum L.) were used to determine the distribution of secondary metabolites and their biosynthetic enzymes. Leaf epidermal layers in this strain are easily separated from the parenchyma. Anthocyanins and flavonol glycosides were localized in epidermal vacuoles only. Among the biosynthetic enzymes studied, phenylalanine ammonia-lyase (PAL, EC 4.3.1.5), S-adenosyl-1-methionine (SAM):caffeic acid and SAM:quercetin methyltransferases (o-dihydric phenol methyltransferase, EC 2.1.1.42) and a flavonoid 7-O-glucosyltransferase (EC 2.4.1.91) were chiefly localized in the parenchyma, whereas trans-cinnamate 4-monooxygenase (EC 1.14.13.11), hydroxycinnamate:CoA ligases (EC 6.2.1.12) and a flavonoid 3-O-glucosyltransferase (EC 2.4.1.91) were found mainly in the epidermis. Flavanone (chalcone) synthase activity was found only in the epidermis, whereas chalcone isomerase (EC 5.5.1.6) was evenly distributed in epidermal and parenchyma tissues.

OBJECTIVE

The aim of this study was to develop a bone metastases module to supplement the European Organisation for Research and Treatment of Cancer Core Questionnaire (EORTC QLQ-C30) or the EORTC QLQ-C15-PAL for patients with bone metastases.

METHODS

Phases 1-2 of module development were conducted in Canada, Australia and Germany according to EORTC QOL group guidelines. Phase 3 was conducted in nine countries in seven languages.

RESULTS

Sixty-one health-related quality of life (HRQOL) issues were generated from health care professionals (n=152) and patients (n=413). This resulted in a 22-item provisional module. Further testing in 170 patients from nine countries resulted in the EORTC QLQ-BM22 module, containing 22 items, conceptualised into both symptom scales, with five painful sites and three pain characteristics, and also functional scales, with eight functional interference and six psychosocial aspects.

CONCLUSIONS

This study provides a provisional comprehensive HRQOL measurement tool for future trials, which will continue to undergo further validation.

Increasing evidence from human and laboratory studies showed the effect of zinc (Zn) on diabetic complications. Nuclear factor-erythroid 2-related factor 2 (Nrf2) plays important role in the prevention of oxidative damage. This study was to define whether Zn statues (deficiency or supplement) affect the Nrf2 expression and function, and also affect the damage severity of human renal tubular (HK11) cells exposed to high glucose (HG) with palmitate (Pal) and kidney of diabetic mice induced by multiple low-dose streptozotocins. For Zn deficiency diabetic mice were treated with Zn chelator PTEN at 5 mg/kg bw daily for 4 months. Results showed that HG/Pal significantly increased the expression of pro-fibrotic mediators, connective tissue growth factor and PAI-1, in HK11 cells, which was exacerbated by TPEN that depleted intracellular free Zn and decreased Nrf2 expression and transcription. Zn supplement prevented the effects of TPEN and also increased Akt and GSK-3β phosphorylation with a decrease in Nrf2 nuclear exporter, Fyn. All these effects of Zn were abolished by Akt inhibitor. Therefore, Zn up-regulates Nrf2 function via activating Akt-mediated inhibition of Fyn function. Treatment of diabetic mice with TPEN decreased renal Zn level and Nrf2 expression and transcription, with an exacerbation of renal oxidative damage, inflammation and fibrosis. These results suggest the essentiality of Zn for Nrf2 expression and transcription function.

L-Phenylalanine is one of the essential amino acids that cannot be synthesized in mammals in adequate amounts to meet the requirements for protein synthesis. Fungi and plants are able to synthesize phenylalanine via the shikimic acid pathway. L-Phenylalanine, derived from the shikimic acid pathway, is used directly for protein synthesis in plants or metabolized through the phenylpropanoid pathway. This phenylpropanoid metabolism leads to the biosynthesis of a wide array of phenylpropanoid secondary products. The first step in this metabolic sequence involves the action of phenylalanine ammonia-lyase (PAL). The discovery of PAL enzyme in fungi and the detection of (14)CO(2) production from (14)C-ring-labeled phenylalanine and cinnamic acid demonstrated that certain fungi can degrade phenylalanine by a pathway involving an initial deamination to cinnamic acid, as happens in plants. In this review, we provide background information on PAL and a recent update on the presence of PAL genes in fungi.

Southern blot analyses of genomic DNA fragments suggest there are five different classes of phenylalanine ammonia-lyase (<em>PAL</em>, EC 4.3.1.5) genomic sequence in tomato (Lycopersicon esculentum). Isolation and subsequent sequence analysis of three examples from genomic libraries reveal highly homologous coding sequences but also a surprisingly high frequency of single point mutations which would truncate protein synthesis. The nucleotide sequence for one of the genes (<em>PAL</em>5) encodes a normal polypeptide of 721 amino acids, interrupted by a 710-base pair intron in the codon for amino acid 139. In contrast, premature stop codons, 363 triplets from the end in <em>PAL</em>1 and 304 triplets from the end in <em>PAL</em>3 would result in substantially (51-43%) shorter polypeptides that are consistent with the protein polymorphism, recently reported in alfalfa (Jorrin, J., and Dixon, R. A. (1990) Plant Physiol. 92, 447-445) but ascribed to protein degradation. S1 mapping of the mRNA termini and polymerase chain reaction analysis of cDNA transcripts indicate that at least one of these truncated coding sequences is expressed, strongly suggesting that at least some of the shorter polypeptides constitute original gene products with a potentially important function.

The function of hydrogen peroxide (H(2)O(2)) as a signal molecule regulating gene expression and cell death induced by external stresses was studied in birch (Betula pendula). Ozone (O(3)), Pseudomonas syringae pv syringae (Pss), and wounding all induced cell death of various extents in birch leaves. This was temporally preceded and closely accompanied by H(2)O(2) accumulation at, and especially surrounding, the lesion sites. O(3) and Pss, along with an artificial H(2)O(2) producing system glucose (Glc)/Glc oxidase, elicited elevated mRNA levels corresponding to genes encoding reactive oxygen species detoxifying enzymes, Pal, Ypr10, and mitochondrial phosphate translocator 1. In addition to the regulation of gene expression, Glc/Glc oxidase also induced endogenous H(2)O(2) production in birch leaves, accompanied by cell death that resembled O(3) and Pss damage. Wound-induced gene expression differed from that induced by O(3) and Pss. Thus, it appears that at least two separate defense pathways can be activated in birch leaves by stress factors, even though the early H(2)O(2) accumulation response is common among them all.

BACKGROUND

Aggregatibacter actinomycetemcomitans is an oral bacterium associated with aggressive forms of periodontitis. Increasing evidence points to a link between periodontitis and cardiovascular diseases, however, the underlying mechanisms are poorly understood. This study investigated the pathogenic potential of free-soluble surface material, released from live planktonic and biofilm A. actinomycetemcomitans cells.

RESULTS

By employing an ex vivo insert model (filter pore size 20 nm) we demonstrated that the A. actinomycetemcomitans strain D7S and its derivatives, in both planktonic and in biofilm life-form, released free-soluble surface material independent of outer membrane vesicles. This material clearly enhanced the production of several proinflammatory cytokines (IL-1 beta, TNF-alpha, IL-6, IL-8, MIP-1 beta) in human whole blood, as evidenced by using a cytokine antibody array and dissociation-enhanced-lanthanide-fluorescent-immunoassay. In agreement with this, quantitative real-time PCR indicated a concomitant increase in transcription of each of these cytokine genes. Experiments in which the LPS activity was blocked with polymyxin B showed that the stimulatory effect was only partly LPS-dependent, suggesting the involvement of additional free-soluble factors. Consistent with this, MALDI-TOF-MS and immunoblotting revealed release of GroEL-like protein in free-soluble form. Conversely, the immunomodulatory toxins, cytolethal distending toxin and leukotoxin, and peptidoglycan-associated lipoprotein, appeared to be less important, as evidenced by studying strain D7S cdt/ltx double, and pal single mutants. In addition to A. actinomycetemcomitans a non-oral species, Escherichia coli strain IHE3034, tested in the same ex vivo model also released free-soluble surface material with proinflammatory activity.

CONCLUSIONS

A. actinomycetemcomitans, grown in biofilm and planktonic form, releases free-soluble surface material independent of outer membrane vesicles, which induces proinflammatory responses in human whole blood. Our findings therefore suggest that release of surface components from live bacterial cells could constitute a mechanism for systemic stimulation and be of particular importance in chronic localized infections, such as periodontitis.

The capacity to migrate from peripheral tissues, where antigen is encountered, to lymphoid organs, where the primary immune response is initiated, is crucial to the immunogenic function of dendritic cells (DC). The skin is a suitable tissue to study migration. DC were observed to gather in distinct nonrandom arrays ("cords") in the dermis upon culture of murine whole skin explants. It is assumed that cords represent lymphatic vessels. Using a similar organ culture model with human split-thickness skin explants, we investigated migration pathways in human skin. We made the following observations. 1) Spontaneous emigration of Langerhans cells took place in skin cultured for 1-3 d. Nonrandom distribution patterns of strongly major histocompatibility complex class II-expressing DC (cords) occurred in cultured dermis. A variable, yet high (>50%) percentage of these DC coexpressed the Birbeck granule-associated antigen "Lag." Ultrastructurally, the cells corresponded to mature DC. 2) Electron microscopy proved that the dermal structures harboring the accumulations of DC (i.e., cords) were typical lymph vessels. Moreover, markers for blood endothelia (monoclonal antibody PAL-E, Factor VIII-related antigen) and markers for cords (strong major histocompatibility complex class II expression on nonrandomly arranged, hairy-appearing cells) were expressed in a mutually exclusive pattern. 3) On epidermal sheets we failed to detect gross changes in the levels of expression of adhesion molecules (CD44, CD54/ ICAM-1, E-cadherin) on keratinocytes in the course of the culture period. The reactivity of a part of the DC in the dermal cords with Birbeck granule-specific monoclonal antibody "Lag" suggests that the migratory population is composed of both epidermal Langerhans cells and dermal DC. We conclude that this organ culture model may prove helpful in resolving pathways and mechanisms of DC migration.

We have identified a new En/Spm-like transposable element, Tdc1, in the 5' flanking region of a phenylalanine ammonia-lyase gene (gDcPAL1) that is normally induced by transferring cells of carrot suspension cultures to fresh liquid medium (transfer or dilution effect). The initial integration into gDcPAL1 occurred more than 4 years after culture initiation. Tdc1 was first detected in gDcPAL1 genomic clones of a genomic library made from cells of the same cultured cell line 7 years after its initiation and thus following repeated subculturing. Twelve years after initiation, about 5-10% of the cells had Tdc1 inserted into the gDcPAL1 gene, indicating that Tdc1 insertion into gDcPAL1 occurred in one (or more) cell(s) during the first 4-7 years of subculturing. These mutant cells did not disappear during numerous passages; instead the proportion of cells having this Tdc1 inserted into gDcPAL1 has been increasing over the last 5 years. The promoter activity and the inducibility by transfer/dilution of the gDcPAL1 gene harboring Tdc1 is reduced relative to wild type. Finally, we show that insertion of a transposable element is one of the mechanisms that can cause variation of plant cell cultures during repeated subculture.

TolB is a periplasmic protein of the cell envelope Tol complex. It is partially membrane associated through an interaction with the outer membrane lipoprotein PAL (peptidoglycan-associated lipoprotein), which also belongs to the Tol system. The interaction of TolB with outer membrane porins of Escherichia coli was investigated with a purified TolB derivative harboring a six-histidine tag. TolB interacted with the trimeric porins OmpF, OmpC, PhoE, and LamB but not with their denatured monomeric forms or OmpA. These interactions took place both in the presence and in the absence of lipopolysaccharide. TolA, an inner membrane component of the Tol system, also interacts with the trimeric porins via its central periplasmic domain (R. Dérouiche, M. Gavioli, H. Bénédetti, A. Prilipov, C. Lazdunski, and R. Lloubès, EMBO J. 15:6408-6415, 1996). In the presence of the purified central domain of TolA (TolAIIHis), the TolB-porin complexes disappeared to form TolAIIHis-porin complexes. These results suggest that the interactions of TolA and TolB with porins might take place in vivo and might be concomitant events participating in porin assembly. They also suggest that the Tol system as a whole may be involved in porin assembly in the outer membrane.

In a mouse model, we have shown previously that macrophages are the principal source of complement C1q. Furthermore, spleen, heart, and brain were found to contain substantial levels of murine C1q-specific mRNA, whereas liver, kidney, lung, and small intestine contained only trace amounts of C1q-specific mRNA. This work addresses the identification of C1q-expressing spleen cells in the rat, using Northern blotting and in situ detection of rat C1q mRNA combined with immunohistochemical analysis. The complete sequence of mRNA encoding the B chain of rat C1q was established. The cloned cDNA was found to hybridize primarily with spleen-derived mRNA of 1.2 kb, and additionally with a novel mRNA species of 3 kb. In situ hybridization together with immunohistochemistry revealed most of the C1q-expressing cells to be located in the red pulp of the spleen, and to be mainly of the monocyte-macrophage lineage, as indicated by coexpression of ED-1, an established marker for this type of cell. In addition, C1q was expressed in S-100-positive but ED-1-negative cells, in germinal center follicular dendritic cells, and in some interdigitating dendritic cells of the periarteriolar lymphatic sheath (PALS). These results indicate that the spleen, containing the above APCs that are all involved to a major extent in the adaptive immune response and are all capable of synthesizing C1q that is involved intimately in the innate immune response, may provide the site at which the innate and adaptive immune systems merge.

Young (n = 24) and old (n = 24) participants rated 160 faces of young and old individuals taken from the CAL/PAL Face Database (Minear & Park, 2004) with regard to attractiveness, likeability, distinctiveness, goal orientation, energy, mood, and age. Ratings are reported for each face separately. Further analyses showed that the age groups differed in their ratings of young and old faces. On average, old participants evaluated the faces as more positive (i.e., more attractive, more energetic) than did young participants. In line with research on a negative aging stereotype, old faces were judged as less positive than young faces. They were, for instance, seen as less attractive, less likeable, less distinctive, less growth-oriented, and less energetic. The findings of the present study can serve as a basis for the selection of appropriate facial stimuli in age-comparative studies of face perception, face processing, or memory for faces. All face-specific data are archived at www.psychonomic.org/archive.