bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repression of motility during fimbrial expression: identification of 14 mrpJ gene paralogues in Proteus mirabilis
Authors: Pearson Melanie M. , Mobley Harry L. T. 
Published: May 2008

Summary Proteus mirabilis alternates between motile and adherent forms. MrpJ, a transcriptional regulator previously reported to repress motility, is encoded at the 3′ end of the mrp fimbrial operon in P. mirabilis. Sequencing of the P. mirabilis genome revealed 14 additional paralogues of mrpJ, 10 of which are associated with fimbrial operons. Twelve of these genes, when overexpressed, repressed motility; several distinct patterns of swarming motility were noted. Expression of 10 of the 14 mrpJ paralogues repressed flagellin (FlaA) synthesis. Alignment of the predicted amino acid sequences of MrpJ and its 14 paralogues revealed a conserved consensus motif (SQQQFSRYE) within the helix‐turn‐helix domain. Site‐directed mutagenesis of these residues coupled with linker insertion mutagenesis of MrpJ confirmed the importance of this domain for repression of motility. Gel shift assays demonstrated that MrpJ and another paralogue UcaJ bind directly to the promoter region of the flagellar master regulator flhDC. Thus, P. mirabilis appears to use a related mechanism to inhibit motility during the production of at least 10 of its predicted fimbriae.
Identification of transcriptional activators for thienamycin and cephamycin C biosynthetic genes within the thienamycin gene cluster from Streptomyces cattleya
Authors: Rodríguez Miriam , Núñez Luz Elena , Braña Alfredo F. , Méndez Carmen , Salas José A. , Blanco Gloria 
Published: May 2008

SummaryTwo regulatory genes, thnI and thnU, were identified in the thienamycin (thn) gene cluster from Streptomyces cattleya. ThnI resembles LysR‐type transcriptional activators and ThnU belongs to the SARP family of transcriptional activators. Their functional role was established after independent inactivation by gene replacement together with transcriptional analysis involving reverse transcription polymerase chain reaction (RT‐PCR). Deletion of thnI abolished thienamycin production showing its involvement in thienamycin biosynthesis. Gene expression analysis applied to the thn gene cluster demonstrated that ThnI is a transcriptional activator essential for thienamycin biosynthesis that regulates the expression of nine genes involved in thienamycin assembly and export (thnH, thnJ, thnK, thnL, thnM, thnN, thnO, thnP and thnQ). Unexpectedly, the thnU disrupted mutant was not affected in thienamycin production but turned out to be essential for cephamycin C biosynthesis. Transcript analysis applied to early and late structural genes for cephamycin C biosynthesis (pcbAB and cmcI), revealed that ThnU is the transcriptional activator of these cephamycin C genes although they are not physically linked to the thn cluster. In addition, it was shown that deletion of thnI has an upregulatory effect on pcbAB and cmcI transcription consistent with a significant increase in cephamycin C biosynthesis in this mutant.
Lymphocyte hyporesponsiveness during filarial nematode infection
Authors: HARNETT W. , HARNETT M. M. 
Published: May 2008

SUMMARY A frequently observed feature of active infection with filarial nematodes is the presence of lymphocytes in the bloodstream that have impaired responsiveness to antigen. It is generally accepted that such a defect in lymphocyte function could contribute to the failure of the immune system to eliminate filarial nematodes. For this reason, understanding the mechanism underlying lymphocyte ‘hyporesponsiveness’ is an important goal for immunologists who study filarial nematodes. Thus, although there has long been an interest in answering questions such as what stage(s) of the nematode causes hyporesponsiveness, more recently, lymphocyte hyporesponsiveness has been increasingly studied at the molecular level. The result of this is that we are now beginning to learn much of the nature and cause of phenotypic changes in the hyporesponsive lymphocyte and also of the identity of the nematode‐derived molecules that induce them. As this information continues to be generated, the challenge will be to use it to find a way of reversing lymphocyte hyporesponsiveness in the hope that this will lead to rejection of filarial nematodes in the parasitized human host.
Protective immunity induced by daily bites from irradiated mosquitoes infected with Plasmodium yoelii
Authors: WONG K. A. , ZHOU A. , RODRIGUEZ A. 
Published: May 2008

SUMMARY Individuals in malaria endemic regions do not develop fully protective immune responses against Plasmodium liver stage infections. In high transmission areas, individuals can be exposed to more than two infective mosquito bites daily. Their exposure to Plasmodium sporozoites, therefore, is in the form of small and frequent doses. This is very different from individuals studied in controlled immunization trials where the delivery of large numbers of radiation‐attenuated sporozoites in a limited number of doses can induce sterile protective immunity. Using irradiated mosquitoes infected with Plasmodium yoelii 17XNL, we tested whether daily bites from a few mosquitoes can induce a protective immune response in mice. This immunization strategy successfully induced a protective response, preventing the development of liver stages when mice were challenged with nonirradiated sporozoites. These results provide further support for the development of liver stage vaccines. They are also a call for further study into why fully protective responses against the liver stage are not seen in individuals from endemic regions.
Contractile roots in succulent monocots: convergence, divergence and adaptation to limited rainfall
Authors: NORTH GRETCHEN B. , BRINTON ERIN K. , GARRETT TADAO Y. 
Published: May 2008

ABSTRACTContractile roots (CRs) that pull shoots further down in the soil are a possible example of convergent evolution in two monocot families, the Agavaceae and the Asphodelaceae. The association between CRs, water uptake and habitat aridity was investigated for agaves, yuccas and aloes by assessing the occurrence of CRs and the amount of root contraction for glasshouse‐grown plants with respect to mean annual rainfall of their native habitats. Structural features of CRs as well as root hydraulic conductance were compared with those of non‐contractile roots (NCRs). CRs occurred in 55% of the 73 species examined, including 64% of the agaves and 85% of the yuccas, but in none of the aloes despite the occurrence of CRs in related genera. The phylogenetic distribution of CRs was consistent with multiple acquisitions or losses of the trait. The amount of root contraction showed a highly significant negative relationship with mean annual rainfall, although other environmental factors may also be important. Radial hydraulic conductance of the basal (contractile) zone exceeded that of the midroot zone for CRs; for NCRs, the opposite was true. Thus, CRs in the species examined may provide a mechanism for greater water uptake near the soil surface in regions with limited rainfall.
Do major oxide tectonic discrimination diagrams work? Evaluating new log‐ratio and discriminant‐analysis‐based diagrams with Indian Ocean mafic volcanics and Asian ophiolites
Authors: Sheth Hetu C. 
Published: May 2008

AbstractMany geochemical diagrams exist that classify old volcanic terranes of ambiguous provenance into various modern plate tectonic settings, with variable success. Recently proposed diagrams, based on log‐ratios and linear discriminant analysis with large datasets of major oxides, were tested here with data for ocean island, arc and mid‐ocean ridge lavas from the Indian Ocean. Success rates are 45–100%, with misclassifications potentially caused by alteration, although alteration demonstrably need not cause misclassification. The diagrams were further applied to some Asian ophiolites, representing Tethyan and Indian ocean crusts, to see if the diagrams confirm their tectonic setting inferred from trace and isotopic data. Lower success rates (30–60%, but 75–100% for specific suites) are not surprising in view of the ubiquitous and complex alteration in ophiolites. Log‐ratio transformation and linear discriminant analysis appear to be powerful methods when discrimination diagrams are based on major oxide data alone.
IMAGING STUDY: Modulation of brain response to emotional images by alcohol cues in alcohol‐dependent patients
Authors: Gilman Jodi M. , Hommer Daniel W. 
Published: May 2008

ABSTRACTAlcohol is often used to modulate mood states. Alcohol drinkers report that they use alcohol both to enhance positive affect and to reduce dysphoria, and alcohol‐dependent patients specifically state reduction of negative affect as a primary reason for drinking. The current study proposes that alcohol cues may reduce negative affect in alcoholics. We used functional magnetic resonance imaging to examine brain activation in response to combination images that juxtaposed negative or positive International Affective Picture System (IAPS) images with an alcohol or non‐alcohol‐containing beverage. We found that in the absence of the alcohol cue, alcoholics showed more activation to negative than to positive images and greater activation than controls to negative images. When the IAPS images were presented with the alcohol cue, there was a decreased difference in activation between the positive and negative images among the alcoholics, and a decreased difference in response to the negative images between controls and alcoholics. Additionally, in the neutral‐beverage conditions, anxiety ratings significantly predicted activation in the right parahippocampal gyrus but did not predict activation when the alcohol cues were presented. In conclusion, the alcohol cues may have modulated cortical networks involved in the processing of emotional stimuli by eliciting a conditioned response in the alcoholics, but not in the controls, which may have decreased responsiveness to the negative images.
Use of pheromone mimic to cause the disintegration and collapse of colonies of tent caterpillars (Malacosoma spp.)
Authors: Fitzgerald T. D. 
Published: May 2008

AbstractThe disruption of the trail‐based communication system of eastern tent caterpillars (ETC) (Malacosoma americanum) and forest tent caterpillars (FTC) (M. disstria) by spraying host trees with a trail pheromone mimic caused the disintegration and collapse of young colonies. A 1‐ppm formulation of 5β‐cholestan‐3‐one or a control formulation was sprayed on trees either before or after eclosion of the caterpillars in the spring. For pre‐eclosion trials, an average of 92% of the FTC colonies on control trees, but only 17% of colonies on treated trees consisted of viable, cohesive aggregates when survival was assessed 5–23 days post‐spray. The remaining colonies had either completely disappeared or were reduced to small, disintegrated fragments. For the ETC, 100% of colonies on control trees and an average of 12% of colonies on treated trees consisted of cohesive aggregates inhabiting tents when survival was assessed 3–41 days post‐spray. The remaining colonies were completely destroyed, reduced to scattered individuals, or to small, disintegrated, shelter‐less fragments. For post‐eclosion trials with the FTC in which colonies were sprayed during their first or second larval stadium, an average of 63% of individuals in control groups but only 7% in treatment groups were still on the sprayed trees 5–18 days post‐spray. For the ETC, colonies were largely unaffected when trees were not sprayed until after the caterpillars had eclosed and established tents. For all trials, the loss of individuals on treated trees was largely attributable to the inability of dispersed and isolated first or second instar caterpillars to maintain secure purchase, causing them to fall from trees and perish. To our knowledge, this is the first study to investigate the potential of manipulating populations of pest species by interfering with a trail‐based, chemical communication system.
Insulin resistance in experimental alcohol‐induced liver disease
Authors: De La Monte Suzanne M , Yeon Jong‐Eun , Tong Ming , Longato Lisa , Chaudhry Rajeev , Pang Mao‐Yin , Duan Kevin , Wands Jack R. 
Published: May 2008

AbstractBackground and Aim:  Chronic ethanol consumption impairs liver regeneration due, in part, to inhibition of insulin signaling. This study characterizes the mechanisms and consequences of ethanol‐impaired insulin signaling in relation to oxidative injury and altered gene expression.Methods:  Long‐Evans rats were fed for 8 weeks with isocaloric liquid diets containing 0% (control) or 37% ethanol (caloric content). Livers were used to examine histopathology, indices of oxidative stress, gene expression required for insulin and insulin‐like growth factor (IGF) signaling, insulin‐responsive gene expression, i.e. glyceraldehydes‐3‐phosphate dehydrogenase (GAPDH) and aspartyl‐asparaginyl‐β‐hydroxylase (AAH), and competitive equilibrium binding to the insulin, IGF‐I, and IGF‐II receptors.Results:  Chronic ethanol exposure caused liver injury with increased hepatocellular steatosis, inflammation, apoptosis, and increased immunoreactivity for activated caspase‐3, 8‐hydroxy‐2′‐deoxyguanosine, and 4‐hydroxy‐2,3‐nonenol. These effects were associated with increased expression of IGF‐I receptor, IGF‐II, and IGF‐II receptor, and expression of IGF‐I, AAH, and GAPDH, which mediate energy metabolism and cell motility/remodeling, and reduced binding to the insulin receptor.Conclusions:  Chronic ethanol‐induced liver injury causes insulin resistance with inhibition of insulin‐responsive genes needed for metabolism, remodeling, and regeneration. In contrast, the IGF‐I and IGF‐II signaling mechanisms remain relatively preserved, suggesting that insulin‐regulated hepatic functions may be selectively vulnerable to the toxic effects of ethanol.
Changing the pathogenetic roadmap of liver fibrosis? Where did it start; where will it go?
Authors: Gressner Olav A , Rizk Mohamed S , Kovalenko Evgeniya , Weiskirchen Ralf , Gressner Axel M 
Published: May 2008

AbstractThe pathophysiology of liver injury has attracted the interest of experimentalists and clinicians over many centuries. With the discovery of liver‐specific pericytes – formerly called fat‐storing cells, Ito‐cells, lipocytes, and currently designated as hepatic stellate cells (HSC) – the insight into the cellular and molecular pathobiology of liver fibrosis has evolved and the pivotal role of HSC as a precursor cell‐type for extracellular matrix–producing myofibroblasts has been established. Although activation and transdifferentiation of HSC to myofibroblasts is still regarded as the pathogenetic key mechanism of fibrogenesis, recent studies point to a prominent heterogeneity of the origin of myofibroblasts. Currently, the generation of matrix‐synthesizing fibroblasts by epithelial–mesenchymal transition, by influx of bone marrow–derived fibrocytes into damaged liver tissue, and by differentiation of circulating monocytes to fibroblasts after homing in the injured liver are discussed as important complementary mechanisms to enlarge the pool of (myo‐)fibroblasts in the fibrosing liver. Among the molecular mediators, transforming growth factor‐beta (TGF‐β) plays a central role, which is controlled by the bone‐morphogenetic protein (BMP)‐7, an important antagonist of TGF‐β action. The newly discovered pathways supplement the linear concept of HSC activation to myofibroblasts, point to fibrosis as a systemic response involving extrahepatic organs and reactions, add further evidence to a more or less uniform concept of organ fibrosis in general (e.g. liver, lung, kidney), and offer innovative approaches for the development of non‐invasive biomarkers and antifibrotic trials.
Ground glass hepatocytes contain pre‐S mutants and represent preneoplastic lesions in chronic hepatitis B virus infection
Authors: Su Ih‐Jen , Wang Hui‐Ching , Wu Han‐Chieh , Huang Wen‐Ya 
Published: May 2008

AbstractThe discovery of “ground glass” hepatocytes (GGH) that contain hepatitis B virus (HBV) surface antigens by Hadziyannis and Popper in 1973 represents a historical landmark in the pathology of chronic HBV infection. Different types of GGH have been correlated to the expression patterns of surface/core antigens and the stages of virus replication. The original two types (designated types I & II) of GGH were found to contain specific pre‐S mutants with deletions over either pre‐S1 or pre‐S2 regions, respectively. Type II GGH consistently harbor pre‐S2 deletion mutants, which can escape from immune attack and grow preferentially to form clusters. Both types of pre‐S mutants can induce endoplasmic reticulum (ER) stress and oxidative DNA damage. The pre‐S2 mutants, albeit inducing a weaker level of ER stress signals, could additionally initiate ER stress‐independent retinoblastoma/adenovirus E2 promoter binding factor/cyclin A signaling through their interaction with c‐Jun activation domain binding protein 1 to degrade p27, illustrating the growth advantage of type II GGH. The combined effects of genomic instability and the proliferation of hepatocytes harboring pre‐S mutants could potentially lead to hepatocarcinogenesis over the decades of chronic HBV infection. The presence of pre‐S mutants in sera was reported to carry a high risk of developing hepatocellular carcinoma (HCC). Furthermore, transgenic mice harboring pre‐S2 mutant plasmids have been shown to develop a dysplastic change of hepatocytes and HCC. Therefore, in addition to being a histological marker of chronic HBV infection, GGH, particularly type II GGH, may represent the preneoplastic lesions of HBV‐related HCC.
A microdiversity study of anammox bacteria reveals a novel Candidatus Scalindua phylotype in marine oxygen minimum zones
Authors: Woebken Dagmar , Lam Phyllis , Kuypers Marcel M. M. , Naqvi S. Wajih A. , Kartal Boran , Strous Marc , Jetten Mike S. M. , Fuchs Bernhard M. , Amann Rudolf 
Published: May 2008

SummaryThe anaerobic oxidation of ammonium (anammox) contributes significantly to the global loss of fixed nitrogen and is carried out by a deep branching monophyletic group of bacteria within the phylum Planctomycetes. Various studies have implicated anammox to be the most important process responsible for the nitrogen loss in the marine oxygen minimum zones (OMZs) with a low diversity of marine anammox bacteria. This comprehensive study investigated the anammox bacteria in the suboxic zone of the Black Sea and in three major OMZs (off Namibia, Peru and in the Arabian Sea). The diversity and population composition of anammox bacteria were investigated by both, the 16S rRNA gene sequences and the 16S‐23S rRNA internal transcribed spacer (ITS). Our results showed that the anammox bacterial sequences of the investigated samples were all closely related to the Candidatus Scalindua genus. However, a greater microdiversity of marine anammox bacteria than previously assumed was observed. Both phylogenetic markers supported the classification of all sequences in two distinct anammox bacterial phylotypes: Candidatus Scalindua clades 1 and 2. Scalindua 1 could be further divided into four distinct clusters, all comprised of sequences from either the Namibian or the Peruvian OMZ. Scalindua 2 consisted of sequences from the Arabian Sea and the Peruvian OMZ and included one previously published 16S rRNA gene sequence from Lake Tanganyika and one from South China Sea sediment (97.9–99.4% sequence identity). This cluster showed only ≤ 97% sequence identity to other known Candidatus Scalindua species. Based on 16S rRNA gene and ITS sequences we propose that the anammox bacteria of Scalindua clade 2 represent a novel anammox bacterial species, for which the name Candidatus Scalindua arabica is proposed. As sequences of this new cluster were found in the Arabian Sea, the Peruvian OMZ, in Lake Tanganyika and in South China sediment, we assume a global distribution of Candidatus Scalindua arabica as it is observed for Candidatus Scalindua sorokinii/brodae (or Scalindua clade 1).
The Canadian Uro‐Oncology Group multicentre phase II study of docetaxel administered every 3 weeks with prednisone in men with metastatic hormone‐refractory prostate cancer progressing after mitoxantrone/prednisone
Authors: Saad Fred , Ruether Dean , Ernst Scott , North Scott , Cheng Tina , Perrotte Paul , Karakiewicz Pierre , Winquist Eric 
Published: May 2008

OBJECTIVETo investigate the use of docetaxel 75 mg/m2 intravenously every 3 weeks plus prednisone 5 mg orally twice daily in men with metastatic hormone‐refractory prostate cancer (HRPC) progressing after first‐line mitoxantrone/prednisone (MP), the primary outcome being progression‐free survival with prostatic‐specific antigen (PSA) and pain response, toxicity and quality of life (QoL) also assessed.PATIENTS AND METHODSThirty patients from four centres were enrolled in the study; all had had previous MP for symptomatic, metastatic HRPC and all had castrate levels of testosterone maintained during therapy.RESULTSAt enrolment, the median age was 69 years, the mean PSA level was 324 ng/dL, and 86% of patients reported pain. There was a PSA response in 57% of the men and a reduction in pain in >60%; the overall QoL was maintained. There were four cases of febrile neutropenia and two treatment‐related deaths. The median progression‐free and overall survival were 5 and 15 months, respectively.CONCLUSIONDocetaxel was associated with high rates of PSA and pain response in this study. Non‐haematological toxicity was similar to that during first‐line treatment, but rates of febrile neutropenia and toxic death appeared to be slightly higher. In selected patients with progressive metastatic HRPC previously treated with mitoxantrone, docetaxel appears to be a beneficial therapeutic option.
Extracorporeal shock‐wave therapy for treating chronic pelvic pain syndrome: a feasibility study and the first clinical results
Authors: Zimmermann Reinhold , Cumpanas Alin , Hoeltl Lorenz , Janetschek Gunther , Stenzl Arnulf , Miclea Florin 
Published: May 2008

OBJECTIVETo investigate the feasibility and clinical outcome of extracorporeal shock‐wave therapy (ESWT) for patients suffering from chronic pelvic pain syndrome (CPPS).PATIENTS AND METHODSThe study included 34 patients who had had CPPS for ≥3 months, who were investigated in two subsequent studies. ESWT was administered using a perineal approach with two different standard ESWT devices with and without an ultrasonographic positioning system. The follow‐up was at 1, 4 and 12 weeks after ESWT, to evaluate the effects on pain, quality of life and voiding. Imaging studies and changes in prostate‐specific antigen (PSA) were used to investigate the safety and side‐effects of ESWT.RESULTSAll patients completed the treatments and follow‐up; there were statistically significant improvements in pain and quality of life after ESWT. Voiding conditions were temporarily improved but with no statistical significance. Perineal ESWT was easy and safe to administer with no anaesthesia on an outpatient basis. Side‐effects could be excluded clinically, by imaging studies and by changes in PSA level.CONCLUSIONPerineal ESWT must be considered as a promising new therapy for CPPS, in particular as it is easy to apply and causes no side‐effects.