bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of the fimB promoter: a case of differential regulation by ppGpp and DksA in vivo
Authors: Åberg Anna , Shingler Victoria , Balsalobre Carlos 
Published: February 2008

SummaryThe expression of type 1 fimbriae is dependent on the intracellular levels of ppGpp through stimulation of fimB transcription. Here we show that in contrast to the previously described decreased fimbriation observed in a ppGpp‐deficient strain, DksA deficiency results in a hyperfimbriated state. In vivo assays show that the effect of DksA deficiency on the type 1 fimbriae occurs at the phase variation level because of elevated transcription from the fimB P2 promoter. In contrast, our in vitro transcription studies demonstrate that ppGpp and DksA can stimulate transcription from the fimB P2 promoter both independently and codependently. We provide evidences that the apparently contradictory results from the in vivo and in vitro transcriptional studies are at least in part a consequence of the increased association of the anti‐pausing factors (GreA and GreB) to the RNA polymerase in the absence of DksA in vivo.
Legionella translocates an E3 ubiquitin ligase that has multiple U‐boxes with distinct functions
Authors: Kubori Tomoko , Hyakutake Akihiro , Nagai Hiroki 
Published: February 2008

Summary Legionella pneumophila has a Dot/Icm type IV secretion system used to translocate a number of ‘effector proteins’ which subvert host cell functions. In this study, we identified 19 novel Dot/Icm substrate proteins using a systematic screening technique. A blast analysis revealed that one of the substrates, which we named LubX (LegionellaU‐box protein), contains two domains that have a remarkable similarity to the U‐box, a domain found in eukaryotic E3 ubiquitin ligases. The expression of LubX is induced upon infection, and most of the LubX produced was translocated into the host cells. LubX has ubiquitin ligase activity in conjunction with UbcH5a or UbcH5c E2 enzymes and mediates polyubiquitination of host Clk1 (Cdc2‐like kinase 1). We demonstrate that one of the U‐boxes (U‐box 1) is critical to the ubiquitin ligation, and the other U‐box (U‐box 2) mediates interaction with Clk1. Thus, the two U‐boxes of LubX have distinct functions, and U‐box 2 plays a non‐canonical role in substrate binding. Although we demonstrate that inhibition of Clk kinase results in a marked reduction of Legionella growth within mouse macrophages, the consequence of Clk1 ubiquitination is still being elucidated. Together, these data suggest that Clk1 is the target host molecule which Legionella modulates during infection.
Gemini/GMOS spectroscopy of the spheroid and globular cluster system of NGC 3923
Authors: Norris Mark A. , Sharples Ray M. , Bridges Terry , Gebhardt Karl , Forbes Duncan A. , Proctor Robert , Raul Faifer Favio , Carlos Forte Juan , Beasley Michael A. , Zepf Stephen E. , Hanes David A. 
Published: February 2008

Abstract
We present a technique to extract ultra-deep diffuse-light spectra from the standard multi-object spectroscopic observations used to investigate extragalactic globular cluster (GC) systems. This technique allows a clean extraction of the spectrum of the host galaxy diffuse light from the same slitlets as the GC targets. We show the utility of the method for investigating the kinematics and stellar populations of galaxies at radii much greater than usually probed in longslit studies, at no additional expense in terms of telescope time. To demonstrate this technique, we present Gemini South Multi-Object Spectrograph (GMOS) spectroscopy of 29 GCs associated with the elliptical galaxy NGC 3923. We compare the measured stellar population parameters of the GC system with those of the spheroid of NGC 3923 at the same projected radii, and find the GCs to have old ages &gt;10 Gyr, [α/Fe]∼ 0.3 and a range of metallicities running from [Z/H]=−1.8 to +0.35. The diffuse light of the galaxy is found to have ages, metallicities and [α/Fe] abundance ratios indistinguishable from those of the red GCs.
Mucosal antibody responses in experimental hookworm infection
Authors: BUNGIRO R. D. , SUN T. , HARRISON L. M. , SHOEMAKER C. B. , CAPPELLO M. 
Published: February 2008

SUMMARY Hookworms are bloodfeeding nematodes that reside in the intestinal mucosa. These parasites secrete proteins that induce robust systemic immune responses in humans and experimental animals. By contrast, mucosal immune responses in and around the site of attachment are not described as well. This paper presents data from studies aimed at examining hookworm‐specific mucosal antibody responses in a hamster model of Ancylostoma ceylanicum infection. Intestinal flush prepared from infected hamsters was analysed by ELISA and shown to be enriched in IgA‐specific for A. ceylanicum excretory–secretory (ES) products. Evaluation of mucosal IgA responses by immunoblot demonstrated that infected hamsters recognized a broad range of ES proteins. Hamsters repeatedly exposed to drug‐terminated infections were shown to have enhanced serum IgG and mucosal IgA responses, as well as a high level of protection from challenge infection. Parasite‐specific IgA was also detected in the faeces of hamsters undergoing a primary infection, and increasing faecal IgA responses were coincident with significant reductions in intestinal worm burdens and faecal ES output over time. Together these results suggest that secretory IgA may act in concert with other components of the mucosal and systemic immune response to promote protective immunity against hookworm infection and/or disease.
Investigating glutamate receptor‐like gene co‐expression inArabidopsis thaliana
Authors: ROY S. J. , GILLIHAM M. , BERGER B. , ESSAH P. A. , CHEFFINGS C. , MILLER A. J. , DAVENPORT R. J. , LIU L.‐H. , SKYNNER M. J. , DAVIES J. M. , RICHARDSON P. , LEIGH R. A. , TESTER M. 
Published: February 2008

ABSTRACTThere is increasing evidence of the important roles of glutamate receptors (GLRs) in plant development and in adaptation to stresses. However, the studies of these putative ion channels, bothin plantaand inXenopusoocytes, may have been limited by our lack of knowledge of possible GLR heteromer formation in plants. We have developed a modification of the single‐cell sampling technique to investigateGLRco‐expression, and thus potential heteromer formation, in single cells ofArabidopsis thalianaleaves. Micro‐EXpression amplification (MEX) has allowed us to amplify gene transcripts from a single cell, enabling expression of up to 100 gene transcripts to be assayed. We measured, on average, the transcripts of five to six differentAtGLRsin a single cell. However, no consistent patterns of co‐expression or cell‐type‐specific expression were detected, except that cells sampled from the same plant showed similar expression profiles. The only discernible feature was the detection ofAtGLR3.7in every cell examined, an observation supported by GUS staining patterns in plants stably expressing promoter::uidAfusions. In addition, we foundAtGLR3.7expression in oocytes induces a Ba2+‐, Ca2+‐ and Na+‐permeable plasma membrane conductance.
Sensitive real‐time PCR detection of Xanthomonas fragariae in strawberry plants
Authors: Vandroemme J. , Baeyen S. , Van Vaerenbergh J. , De Vos P. , Maes M. 
Published: February 2008

Xanthomonas fragariae, the causal agent of angular leaf spot on strawberry, is a quarantine organism in strawberry propagation material in the European Union. For the reliable screening of planting material for latent infections, a real‐time PCR assay based on Taqman® chemistry for the detection of X. fragariae was developed. Primers and probe sequences were based on a DNA fragment amplified by a previously reported X. fragariae‐specific technique. The sequence of this genomic fragment had no significant similarity with any published GenBank sequence. Specificity of the designed assay was tested with an extended range of X. fragariae collection strains and isolates, with other Xanthomonas spp. and with unidentified bacterial isolates from strawberry plants. A nested PCR, which until now was the reference method for sensitive detection in planta, cross‐reacted with the reference strain of Xanthomonas campestris pv. campestris. In combination with an elaborated DNA extraction procedure, the Taqman® PCR enabled reliable detection down to 300 colony forming units in a 100 mg strawberry leaf sample. The assay offers a new tool for epidemiological research and for sanitary control of plant material with low level or latent infections of X. fragariae.
Co‐culture of Head and Neck Squamous Cell Carcinoma Spheroids with Autologous Monocytes Predicts Prognosis
Authors: Kross K. W. , Heimdal J. H. , Olsnes C. , Olofsson J. , Aarstad H. J. 
Published: February 2008

AbstractCo‐culture of monocytes with autologous fragment (F) spheroids originating from malignant (M) tumour or benign (B) control mucosa of head and neck squamous cell carcinoma (HNSCC) yields interleukin (IL)‐6 and monocyte chemo‐attractant protein (MCP)‐1 secretion. This study investigates the association between this cytokine co‐culture response and prognosis. Analysis of IL‐6 and MCP‐1 content of supernatants from monocytes in vitro co‐culture with autologous MF‐ or BF‐spheroids was investigated in a cohort of HNSCC patients (n = 65) diagnosed between 1998 and 2005, all of whom were treated with curative intent by primary surgery. The IL‐6 response was expressed as a fraction of the lipopolysaccharid response of the same batch of monocytes. Recurrence, survival and causes of death were then established following the second part of 2005. MCP‐1 levels did not predict prognosis. We found that increased levels of IL‐6 from autologous monocytes in co‐culture with MF‐spheroids predicted recurrence with a hazard ratio (HR) of 1.5 [confidence interval (CI): 1.01–2.60; P = 0.05] and co‐culture with BF‐spheroids and monocytes predicted recurrence (HR = 4.17; CI: 1.54–11.29; P = 0.005). The same results where obtained in addition with TNM stage of the patients. Simultaneous analysis of BF‐ and MF‐spheroid co‐culture IL‐6 responses as well as adjustment for age and TNM stage of the patients allowed prediction of total survival (HR = 3.1; CI: 1.11–8.56; P = 0.03) based on BF co‐culture levels. IL‐6 secreted upon in vitro co‐culture with monocytes and BF‐spheroids predicts recurrence and prognosis, whereas co‐culture with monocytes and MF‐spheroids predicts recurrence.
Combinatorial interactions of multiple cis‐elements regulating the induction of the Arabidopsis XERO2 dehydrin gene by abscisic acid and cold
Authors: Chung Susanna , Parish Roger W. 
Published: February 2008

SummaryMultiple combinations of mutations in the promoter of the XERO2 dehydrin gene were used to identify elements involved in ABA and cold induction. Mutating one of the three ACGT elements (ACGT1) increases expression in the absence of cold or ABA. An AT‐rich element is a novel partner (coupling element) of ACGT‐containing ABA‐responsive cis‐elements. A 12‐bp palindrome also acts as a coupling element for ABA induction and includes one of the three dehydration‐responsive element/C‐repeat (DRE/CRT) elements and two overlapping motifs (TGTCG and TCGGC) previously shown to be statistically enriched in ABA‐dependent and ‘VP1 or ABA’‐dependent activated genes (Plant Physiol. 2005; 139:437). At least two of the DRE/CRT elements are required for significant cold induction. During cold induction the AT‐rich element also functions as a coupling element and ACGT1 is involved in repressing this induction. Two of the ACGT and DRE/CRT elements overlap, and mutating a single base in the ACGT of either of the two GCCGACGT sequences while retaining a DRE element reduced both ABA and cold induction. Changing the spatial relationships between the elements by deletion, inversion or insertion of DNA sequences reduced both cold and ABA induction. Overexpression of CBF1, −2 or −3 induced XERO2 expression in untreated plants. The ABI5 transcription factor may have a role in ABA‐induced XERO2 expression, whereas ABI3 and ABI4 do not. The GCA2 gene was essential for both cold and ABA induction. A combination of the same overlapping and shared elements is used in the regulation of transcription by ABA and cold.
SMAP29 congeners demonstrate activity against oral bacteria and reduced toxicity against oral keratinocytes
Authors: Weistroffer P. L. , Joly S. , Srikantha R. , Tack B. F. , Brogden K. A. , Guthmiller J. M. 
Published: February 2008

Introduction:  Cathelicidins are antimicrobial peptides found in epithelial and mucosal tissues as well as the secondary granules of neutrophils. SMAP29, a sheep cathelicidin, has differential antimicrobial properties against various pathogens, including periodontal organisms. The purpose of this study was to evaluate the antimicrobial properties and cytotoxicity of SMAP29, SMAP28, and three congeners (SMAP18A, SMAP18D, and SMAP14A).Methods:  The peptides at concentrations ranging from 0.25 to 250 μg/ml were tested for their activity against multiple strains of Streptococcus mutans, Streptococcus sanguis, Actinomyces israelii, Actinomyces naeslundii, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Peptostreptococcus micros, and Porphyromonas gingivalis using a radial diffusion assay. Cytotoxicity of keratinocytes was evaluated by measuring lactate dehydrogenase release after incubation with the individual peptides.Results:  SMAP28, thought to be the biologically active peptide, was the most potent antimicrobial (range of minimum inhibitory concentrations 0.06–7.03 μg/ml, P < 0.05); however, the activity of SMAP28 and SMAP29 was strongly associated (r = 0.933). The congeners also demonstrated antimicrobial activity against the bacteria tested (range of minimum inhibitory concnetrations 0.21–79 μg/ml). Overall, F. nucleatum was the most susceptible organism, while P. gingivalis was the least susceptible. Keratinocyte cytotoxicity was dependent on peptide length and dose. SMAP28 was the most cytotoxic, while SMAP14A was the least cytotoxic.Conclusion:  The antimicrobial activities against oral microorganisms and the minimal toxicity seen in this study suggest that the congeners of SMAP29 may serve as an alternative to traditional antibiotics in the prevention and treatment of periodontal and other oral diseases.
Distribution of Porphyromonas gingivalis fimA genotypes in cardiovascular specimens from Japanese patients
Authors: Nakano K. , Inaba H. , Nomura R. , Nemoto H. , Takeuchi H. , Yoshioka H. , Toda K. , Taniguchi K. , Amano A. , Ooshima T. 
Published: February 2008

Introduction:  Porphyromonas gingivalis, a major periodontal pathogen, is gaining increasing attention for its possible association with cardiovascular diseases. Its fimbriae are classified into six genotypes (types I–V and Ib) based on the diversity of the fimA genes encoding the fimbrial subunits. In this study, fimA genotypic distribution was analyzed in P. gingivalis‐infected cardiovascular specimens.Methods:  A total of 112 heart valves and 80 atheromatous plaque specimens were collected from patients undergoing cardiovascular surgery, as well as 56 dental plaque specimens. Bacterial DNA was extracted from each, and polymerase chain reaction analysis was carried out with a P. gingivalis‐specific set of primers. P. gingivalis‐positive specimens were further analyzed to discriminate the fimA genotype using polymerase chain reaction with fimA type‐specific primer sets.Results:  P. gingivalis was detected in 10.4% of the cardiovascular specimens and 50.0% of the dental plaque samples. In the latter, type II was most frequently detected (35.7%), followed by types I (28.6%) and IV (21.4%), while types IV and II were detected with considerable frequencies of 45.0% and 30.0%, respectively, in the cardiovascular specimens. In contrast, the occurrence of type I was limited (5.0%) in the cardiovascular specimens.Conclusion:  These results suggest that specific fimA genotypic clones, which are reportedly associated with periodontitis, are also frequently harbored in cardiovascular specimens, indicating the possible involvement of type II and IV clones in the initiation and progression of cardiovascular diseases.
Increased interleukin‐18 in gingival crevicular fluid from periodontitis patients
Authors: Figueredo C. M. , Rescala B. , Teles R. P. , Teles F. P. , Fischer R. G. , Haffajee A. D. , Socransky S. S. , Gustafsson A. 
Published: February 2008

Introduction:  This study aimed to measure the levels of interleukin‐18 (IL‐18) in inflamed shallow sites and inflamed deep sites in patients with periodontitis and to compare the data with results from inflamed shallow sites in patients with gingivitis. A secondary aim was to examine the composition of the subgingival microbiota in the sampled sites.Methods:  Gingival crevicular fluid was collected from five gingivitis sites and five periodontitis sites from 18 patients with chronic periodontitis, and from five gingivitis sites from 15 patients with gingivitis. Samples from each site category were pooled and IL‐18 levels were measured using an enzyme‐linked immunosorbent assay. The subgingival microbiota was analyzed by checkerboard DNA–DNA hybridization.Results:  All clinical parameters and gingival crevicular fluid volumes were higher in periodontitis sites compared with gingivitis sites from patients with periodontitis and gingivitis. The total amount of IL‐18 was higher in periodontitis sites than gingivitis sites in both periodontitis (P = 0.018) and gingivitis (P = 0.002) patients and was higher in gingivitis sites from periodontitis patients than in those from gingivitis patients (P = 0.015). There were higher levels of Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola (red complex species) in periodontitis sites compared with gingivitis sites in both the periodontitis and gingivitis patients (P < 0.001).Conclusion:  Levels of IL‐18 were higher in patients with chronic periodontitis compared with patients with gingivitis, even at sites with similar pocket depths. The presence of similar levels of red complex species in gingivitis sites from periodontitis patients and from gingivitis patients suggested that the higher levels of IL‐18 were not associated with a different microbial challenge.
Color‐Based Association Among Heterospecifics in Lake Malaŵi Rock‐Dwelling Cichlids
Authors: Jordan Rebecca C. 
Published: February 2008

AbstractFemale mate choice can be an imperfect barrier against hybridization. Among the cichlid fishes of the East African great lakes, sexual selection on male nuptial coloration has been noted as being particularly important for reproductive isolation among closely related lineages. Diversification of the rock‐dwelling cichlids of Lake Malaŵi has led to a repeating pattern of color morphs wherein more distantly related species may look more similar than a more closely related pair. Using members of the Metriaclima zebra group and a heterogener, I tested the hypothesis that females would spend greater time associating with males more similarly colored to her species than females would with divergently colored, although more closely related males. Experimental results were consistent with this hypothesis, thus supporting the speculation and some field observation that mate choice can fail as a barrier to hybridization if a female encounters a distantly related male that shares the nuptial coloration of males of her own species and color morph. This notion is discussed in the broader context of both the adaptive and non‐adaptive mechanisms that have been suggested to be important to the radiation of this group.
Sexual Cannibalism in the Brown Widow Spider (Latrodectus geometricus)
Authors: Segoli Michal , Arieli Ruthie , Sierwald Petra , Harari Ally R. , Lubin Yael 
Published: February 2008

AbstractSexual cannibalism may represent an extreme form of male monogamy. According to this view, males gain reproductive success by sacrificing themselves to females. We studied the occurrence and timing of sexual cannibalism in the brown widow spiderLatrodectus geometricusand compared male courtship and mating behavior with virgin and with previously mated females.We found that events of sexual cannibalism are frequent, that they occur during copulation and that males initiate cannibalism by placing the abdomen in front of the female’s mouth‐parts during copulation (somersault behavior). Both the somersaults and mating occurred more frequently with virgins than with previously mated females. Our results support the hypothesis that sexual cannibalism is a male strategy in this species. The somersault behavior was previously known only from the redback spider,Latrodectus hasselti.It is as yet unknown whether self‐sacrifice has evolved more than once in this genus.
Different Forms of Vigilance in Response to the Presence of Predators and Conspecifics in a Group‐Living Mammal, the European Rabbit
Authors: Monclús Raquel , Rödel Heiko G. 
Published: February 2008

AbstractIn group‐living mammals, the major functions of vigilance are to detect the presence of predators and to monitor the movements of conspecific competitors, i.e. of potential opponents in agonistic encounters. The minimum distance to such a conspecific competitor that an animal considers safe is usually lower than to a predator, whereas the frequency of encounters with conspecifics is higher. Therefore, the acquisition of information about a predator or about a conspecific could lead to the existence of at least two different modes of vigilance behaviour. The aim of the present study was to describe and compare different forms of vigilance behaviour that European rabbits, Oryctolagus cuniculus, display in anti‐predator and social contexts. We conducted an observational study on individually marked animals from a field enclosure population. We recorded social interactions of the animals, the presence of aerial predators (common buzzard Buteo buteo), and the vigilance behaviour of the rabbits. We distinguished between two forms of vigilance of different intensity: subtle and overt. The frequencies of both forms of vigilance displayed by the rabbits differed significantly in occurrence, duration, and distribution over time. Females and males showed higher frequencies of overt but not subtle vigilance when buzzards were present. In contrast, the presence of conspecifics in close proximity affected the display of subtle but not overt vigilance: males increased the frequency of subtle vigilance when other males were close. Females increased subtle vigilance in proximity of males and females; however, this effect was only apparent in females with a more unstable social situation. In conclusion, European rabbits differentially increased two different forms of vigilance behaviour in social and anti‐predator contexts.