bluuebunny/crossref_metadata_2025_split huggingface dataset:
Circadian gene mPer2 overexpression induces cancer cell apoptosis
Authors: Hua Hui , Wang Yueqi , Wan Chaomin , Liu Yanyou , Zhu Bin , Yang Chunlei , Wang Xiaojia , Wang Zhengrong , Cornelissen–Guillaume Germaine , Halberg Franz 
Published: April 2006

The Period2 gene, an indispensable component of the circadian clock, not only modulates circadian oscillations, but also regulates organic function. We examined whether overexpression of the mouse Period2 gene (mPer2) in tumor cells influences cell growth and induces apoptosis. Overexpression of PERIOD2 in the mouse Lewis lung carcinoma cell line (LLC) and mammary carcinoma cell line (EMT6) results in reduced cellular proliferation and rapid apoptosis, but not in NIH 3T3 cells. Overexpressed mPER2 also altered the expression of apoptosis‐related genes. The mRNA and protein levels of c‐Myc, Bcl‐XL and Bcl‐2 were downregulated, whereas the expression of p53 and bax was upregulated in mPER2‐overexpressing LLC cells compared with control cells transferred with empty plasmid. Our results suggest that the circadian gene mPeriod2 may play an important role in tumor suppression by inducing apoptotic cell death, which is attributable to enhanced pro‐apoptotis signaling and attenuated anti‐apoptosis processes. (Cancer Sci 2006; 97: 589–596)
PARK2/PACRG polymorphisms and susceptibility to typhoid and paratyphoid fever
Authors: Ali S , Vollaard A M , Widjaja S , Surjadi C , Van De Vosse E , Van Dissel J T 
Published: April 2006

Summary
Host genetic factors may contribute to susceptibility to and outcome in infectious diseases. Recently polymorphisms in PARK2/PACRG, a gene cluster linked to ubiquitination and proteasome-mediated protein degradation, were found to be associated with manifest infection by M. leprae. Here, we address whether these polymorphisms are associated with susceptibility to infection with Salmonella typhi and S. paratyphi A, intracellular pathogens that upon infection of humans share with mycobacteria aspects of the hosts’ immune response. The polymorphisms of PARK_e01(−697), PARK2_e01(−2599), rs1333955 and rs1040079 were analysed by polymerase chain reaction and restriction fragment length polymorphism in a case-control study of typhoid and paratyphoid fever patients in an endemic area in Jakarta, Indonesia. For this study, samples were obtained from patients with blood culture-confirmed typhoid fever (n = 90), paratyphoid fever (n = 26) and fever controls (n = 337) in a passive, community-based surveillance and compared to those of randomly selected community controls (n = 322) from the same city area. The PARK2_e01(−2599) allele T was significantly associated with typhoid and paratyphoid fever (OR: 1·51, 95%CI: 1·02–2·23) but the other polymorphisms, PARK2_e01(−697), rs1333955 and rs1040079, were not associated. Although within the PARK2/PACRG gene cluster the PARK2_e01(−2599) allele T was most strongly associated with leprosy (OR∼ 3–5), the association with typhoid is much less strong. Our findings suggest that this polymorphism in PARK2/PACRG plays a small but significant role in susceptibility to the intracellular pathogens S. typhi and S. paratyphi.
Preferential recognition of the phosphorylated major linear B-cell epitope of La/SSB 349–368aa by anti-La/SSB autoantibodies from patients with systemic autoimmune diseases
Authors: Terzoglou A G , Routsias J G , Avrameas S , Moutsopoulos H M , Tzioufas A G 
Published: April 2006

SummarySera from patients with primary Sjögren Syndrome (pSS) or Systemic Lupus Erythematosus (SLE) often contain autoantibodies directed against La/SSB. The sequence 349–368aa represents the major B-cell epitope of La/SSB, also it contains, at position 366, a serine aminoacid residue which constitutes the main phosphorylation site of the protein. In this study we investigated the differential recognition of the 349–368aa epitope and its phosphorylated form by antibodies found in sera from patients with systemic autoimmune diseases. Peptides corresponding to the sequence of the unphosphorylated (pep349–368aa) and the phosphorylated form (pep349–368aaPh) of the La/SSB epitope 349–368aa, as well as to a truncated form spanning the sequence 349–364aa and lacking the phosphorylation site (pep349–364aa), were synthesized. Sera from 53 patients with pSS and SLE with anti-La/SSB specificity, 30 patients with pSS and SLE without anti-La/SSB antibodies, 25 patients with rheumatoid arthritis and 32 healthy individuals were investigated by ELISA experiments. Autoantibodies to pep349–368aaPh were detected in sera of anti-La/SSB positive patients with a higher prevalence compared to the pep349–368aa (66%versus 45%). Pep349–368aaPh inhibited the antibody binding almost completely (92%), while pep349–368aa inhibited the binding only partially (45%). Anti-La/SSB antibodies presented a higher relative avidity for the phosphorylated than the unphosphorylated peptide. Immunoadsorbent experiments using the truncated peptide pep349–364aa indicated that the flowthrough showed a selective specificity for pep349–368aaPh, while the eluted antibodies reacted with both peptide analogues of the La/SSB epitope. These data suggest that sera from pSS and SLE patients with anti-La/SSB reactivity possess autoantibodies that bind more frequently and with a higher avidity to the phosphorylated major B-cell epitope of the molecule.
Characterization of a conjugative transposon integrase, IntDOT
Authors: Malanowska Karolina , Salyers Abigail A. , Gardner Jeffrey F. 
Published: April 2006

SummarySequence analysis revealed that the integrase of the Bacteroides conjugative transposon CTnDOT (IntDOT) might be a member of the tyrosine recombinase family because IntDOT has five of six highly conserved residues found in the catalytic domains of tyrosine recombinases. Yet, IntDOT catalyses a reaction that appears to differ in some respects from well‐studied tyrosine recombinases such as that of phage λ. To assess the importance of the conserved residues, we changed residues in IntDOT that align with conserved residues in tyrosine recombinases. Some substitutions resulted in a complete loss or significant decrease of integration activity in vivo. The ability of the mutant proteins to cleave and ligate CTnDOT attachment site (attDOT) DNA in vitro in general paralleled the in vivo results, but the H345A mutant, which had a wild‐type level of integration in vivo, exhibited a slightly lower level of cleavage and ligation in vitro. Our results confirm the hypothesis that IntDOT belongs to the tyrosine recombinase family, but the catalytic core of the protein seems to have somewhat different organization. Previous DNA sequence analyses showed that CTnDOT att sites contain 5 bp non‐homologous coupling sequences which were assumed to define the putative staggered sites of cleavage. However, cleavage assays showed that one of the cleavage sites is 2 bp away from the junction of CTnDOT and coupling sequence DNA. The site is in a region of homology that is conserved in CTnDOT att sites.
The Campylobacter jejuni PEB1a adhesin is an aspartate/glutamate‐binding protein of an ABC transporter essential for microaerobic growth on dicarboxylic amino acids
Authors: Del Rocio Leon‐Kempis Maria , Guccione Edward , Mulholland Francis , Williamson Michael P. , Kelly David J. 
Published: April 2006

SummaryThe PEB1a protein of the gastrointestinal pathogen Campylobacter jejuni mediates interactions with epithelial cells and is an important factor in host colonization. Cell fractionation and immunoblotting showed that PEB1a is most abundant in the periplasm of C. jejuni, and is detectable in the culture supernatant but not in the inner or outer membrane. The protein is homologous with periplasmic‐binding proteins associated with ABC transporters and we show by fluorescence spectroscopy that purified recombinant PEB1a binds l‐aspartate and l‐glutamate with sub µM Kd values. Binding of l‐14C‐aspartate or l‐14C‐glutamate was strongly out‐competed by excess unlabelled aspartate or glutamate but only poorly by asparagine and glutamine. A mutant in the Cj0921c gene, encoding PEB1a, was completely unable to transport 5 µM l‐14C‐glutamate and showed a large reduction (∼20‐fold) in the rate of l‐14C‐aspartate transport compared with the wild type. Although microaerobic growth of this mutant was little affected in complex media, growth on aspartate or glutamate in defined media was completely prevented, whereas growth with serine was similar to wild type. 1H‐NMR analysis of the culture supernatants of the Cj0921c mutant showed some utilization of aspartate but not glutamate, consistent with the transport data. It is concluded that in addition to the established role of PEB1a as an adhesin, the PEB1 transport system plays a key role in the utilization of aspartate and glutamate, which may be important in vivo carbon sources for this pathogen.
Regulated expression of glutamyl‐tRNA synthetase is directed by a mobile genetic element in the cyanobacterium Tolypothrix sp. PCC 7601
Authors: Luque Ignacio , Andújar Alfonso , Jia Lin , Zabulon Gérald , De Marsac Nicole Tandeau , Flores Enrique , Houmard Jean 
Published: April 2006

SummaryThe genome of Tolypothrix sp. PCC 7601 carries two copies of a novel insertion sequence, ISTosp1. One of the two copies is located upstream of the gene encoding glutamyl‐tRNA synthetase, an enzyme playing a key role in protein and pigment synthesis. The tnpA gene of the IS element and gltX were co‐transcribed and their expression was transiently upregulated upon retrieval of the ammonium source irrespective of whether nitrate or no nitrogen source were available. The second copy is also transcribed and shows a similar regulatory pattern. Structural elements of the promoter (−10 and −35 sequences) directing the expression of the tnpA‐gltX operon have been localized within the IS. Regulatory sequences involving the NtcA transcription factor in the control of tnpA‐gltX expression were found both within and in sequences upstream of the insertion element. The expression of gltX in a closely related cyanobacterium, Nostoc sp. PCC 7120, which lacks the insertion upstream of gltX, decreased upon ammonium retrieval, a regulatory pattern that markedly differs from that observed in Tolypothrix sp. PCC 7601. ISTosp1 constitutes a good example of how cells can make use of a transposable element to evolve an original regulatory mechanism.
M. tuberculosis Rv2252 encodes a diacylglycerol kinase involved in the biosynthesis of phosphatidylinositol mannosides (PIMs)
Authors: Owens Róisín M. , Hsu Fong Fu , VanderVen Brian C. , Purdy Georgiana E. , Hesteande Elizabeth , Giannakas Peter , Sacchettini James C. , McKinney John D. , Hill Preston J. , Belisle John T. , Butcher Barbara A. , Pethe Kevin , Russell David G. 
Published: April 2006

SummaryPhosphorylated lipids play important roles in biological systems, not only as structural moieties but also as modulators of cellular function. Phospholipids of pathogenic bacteria are known to play roles both as membrane components and as factors that modulate the infectious process. Mycobacterium tuberculosis is, however, noteworthy in that it has an extremely diverse repertoire of biologically active phosphorylated lipids that, in the absence of a specialized protein translocation system, appear to constitute the main means of communication with the host. Many of these lipids are derived from phosphatidylinositol (PI) that is differentially processed to give rise to phosphatidylinositol mannosides (PIMs) or lipoarabinomannan. In preliminary studies on the lipid processing enzymes associated with the bacterial cell wall, a kinase activity was noted that gave rise to a novel lipid species released by the bacterium. It was determined that this kinase activity was encoded by the ORF Rv2252. Rv2252 demonstrates the capacity to phosphorylate various amphipathic lipids of host and bacterial origin, in particular a M. tuberculosis derived diacylglycerol. Targeted deletion of the rv2252 gene resulted in disruption of the production of certain higher order PIM species, suggesting a role for Rv2252 in the biosynthetic pathway of PI, a PIM precursor.
Tonoplast‐located GmCLC1 and GmNHX1 from soybean enhance NaCl tolerance in transgenic bright yellow (BY)‐2 cells
Authors: LI WING‐YEN FRANCISCA , WONG FUK‐LING , TSAI SAU‐NA , PHANG TSUI‐HUNG , SHAO GUIHUA , LAM HON‐MING 
Published: April 2006

ABSTRACTGenes encoding ion transporters that regulate ion homeostasis in soybean have not been carefully investigated. Using degenerate primers, we cloned a putative chloride channel gene (GmCLC1) and a putative Na+/H+ antiporter gene (GmNHX1) from soybean. Confocal microscopic studies using yellow fluorescent fusion proteins revealed that GmCLC1 and GmNHX1 were both localized on tonoplast. The expressions of GmCLC1 and GmNHX1 were both induced by NaCl or dehydration stress imposed by polyethylene glycol (PEG). Using mitochondrial integrity and cell death as the damage indicators, a clear alleviation under NaCl stress (but not PEG stress) was observed in both GmCLC1 and GmNHX1 transgenic cells. Using fluorescent dye staining and quenching, respectively, a higher concentration of chloride ion (Cl–) or sodium ion (Na+) was observed in isolated vacuoles in the cells of GmCLC1 and of GmNHX1 transgenic lines. Our result suggested that these vacuolar‐located ion transporters function to sequester ions from cytoplasm into vacuole to reduce its toxic effects.
Genetic diversity and host differentiation among isolates of Phytophthora infestans from cultivated potato and wild solanaceous hosts in Peru
Authors: Garry G. , Forbes G. A. , Salas A. , Santa Cruz M. , Perez W. G. , Nelson R. J. 
Published: April 2006

To test the hypothesis that isolates of Phytophthora infestans attacking wild Solanaceae exhibit specialization for particular host species, 115 isolates of P. infestans were collected from cultivated potatoes, nontuber‐bearing Solanum spp. of the Basarthrum section and wild tomatoes from five departments in the northern and central highlands of Peru, and characterized using several neutral markers. All isolates belonged to one of four clonal lineages described previously in Peru: EC‐1, US‐1, PE‐3 and PE‐7. There was a strong association of three lineages with host species: PE‐3 was only isolated from cultivated potato, while PE‐7 and US‐1 were only isolated from nontuber‐bearing Solanum spp. (Basarthrum section and wild tomatoes). EC‐1 was isolated from all host groups sampled. A subset (n = 74) of the isolates was evaluated for metalaxyl resistance. High levels of resistance were found almost exclusively in EC‐1 and PE‐3, while US‐1 and PE‐7 isolates were generally sensitive. In a detached‐leaf assay for lesion diameter using five EC‐1 isolates from S. caripense and seven EC‐1 isolates from cultivated potato, there was a significant interaction between isolate origin and inoculated host, caused by higher aggressiveness of EC‐1 from cultivated potato on its host of origin. In a comparison of EC‐1 (seven isolates from cultivated potato) and US‐1 (three isolates from S. caripense), each pathogen lineage was more aggressive on its original host species, causing a highly significant interaction between isolate origin and inoculated host. Wild tomatoes and nontuber‐bearing Solanum spp. harbour several pathogen lineages in Peru and could serve as reservoirs of inoculum that might contribute to epidemics on potato or tomato. Potential risks associated with the use of wild Solanum hosts as sources of resistance to P. infestans are discussed.
AtNAP, a NAC family transcription factor, has an important role in leaf senescence
Authors: Guo Yongfeng , Gan Susheng 
Published: April 2006

SummaryLeaf senescence is a unique developmental process that is characterized by massive programmed cell death and nutrient recycling. The underlying molecular regulatory mechanisms are not well understood. Here we report the functional analysis of AtNAP, a gene encoding a NAC family transcription factor. Expression of this gene is closely associated with the senescence process of Arabidopsis rosette leaves. Leaf senescence in two T‐DNA insertion lines of this gene is significantly delayed. The T‐DNA knockout plants are otherwise normal. The mutant phenotype can be restored to wild‐type by the intact AtNAP, as well as by its homologs in rice and kidney bean plants that are also upregulated during leaf senescence. Furthermore, inducible overexpression of AtNAP causes precocious senescence. These data strongly suggest that AtNAP and its homologs play an important role in leaf senescence in Arabidopsis and possibly in other plant species.
TT8 controls its own expression in a feedback regulation involving TTG1 and homologous MYB and bHLH factors, allowing a strong and cell‐specific accumulation of flavonoids in Arabidopsis thaliana
Authors: Baudry Antoine , Caboche Michel , Lepiniec Loïc 
Published: April 2006

SummaryThe control of TT8 expression was investigated in this study, and it was demonstrated that it constitutes a major regulatory step in the specific activation of the expression of flavonoid structural genes. First, the GUS activity generated in planta from a TT8::uidA construct revealed cell‐specific activation of the TT8 promoter consistent with the known involvement of the TT8 bHLH factor in proanthocyanidin, anthocyanin and mucilage biosynthesis. Moreover, the activity of this reporter construct was strongly affected in ttg1, TT2 overexpressers (OE), and PAP1‐OE, suggesting interplay between TT2, PAP1, TTG1 and the activation of the TT8 promoter in planta. To further investigate the mechanisms involved, we used 35S::TT2‐GR and 35S::TTG1‐GR transgenic plants (expressing fusion proteins with the glucocorticoid receptor), as well as one‐hybrid experiments, to determine the direct effect of these factors on TT8 expression. Interestingly, in vivo binding of TT2 and PAP1 to the TT8 promoter was dependent on the simultaneous expression of TT8 or the homologous bHLH factors GL3 and EGL3. Consistent with these results, the activity of the TT8::uidA reporter was strongly affected in the seed endothelium of a tt8 mutant. Similarly, a strong decrease in the level of TT8 mRNA was detected in the siliques of a gl3 × egl3 mutant and in plants that express a dominant negative form of the PAP1 protein, suggesting that TT8 expression is controlled by different combinations of MYB and bHLH factors in planta. The importance of this positive feedback mechanism in the strong and specific induction of proanthocyanidin biosynthesis in the seed coat of Arabidopsis thaliana is discussed.
The Arabidopsis SPA1 gene is required for circadian clock function and photoperiodic flowering
Authors: Ishikawa Masaki , Kiba Takatoshi , Chua Nam‐Hai 
Published: April 2006

SummaryArabidopsis phytochrome A (phyA) regulates not only seed germination and seedling de‐etiolation but also circadian rhythms and flowering time in adult plants. The SUPPRESSOR OF PHYA‐105 (SPA1) acts as a negative regulator of phyA‐mediated de‐etiolation of young seedlings, but its roles in adult plants have not yet been described. Here, we show that SPA1 is involved in regulating circadian rhythms and flowering time in plants. Under constant light, the abundance of SPA1 protein exhibited circadian regulation, whereas under constant darkness, SPA1 protein levels remained unchanged. These results indicate that the SPA1 protein is controlled by the circadian clock and light signals. In addition, the spa1‐3 mutation slightly shortened the circadian period of CCA1, TOC1/PRR1 and SPA1 transcript accumulation under constant light. Phenotypic analysis showed that the spa1‐3 mutant flowers early under short‐day (SD) but not long‐day (LD) conditions. Consistent with this finding, transcripts encoding flowering locus T (FT), which promotes flowering, increased in spa1‐3 under only SD conditions, although the CONSTANS (CO) transcript level was not affected under either SD nor LD conditions. Our results indicate that SPA1 not only negatively controls phyA‐mediated signaling in seedlings, but also regulates circadian rhythms and flowering time in plants.
Prevalence of celiac disease among school children in Punjab, North India
Authors: Sood Ajit , Midha Vandana , Sood Neena , Avasthi Gurcharan , Sehgal Alok 
Published: April 2006

AbstractBackground:  Celiac disease, as of today, is said to exist in almost all parts of the world, although it is rare among people of purely African–Caribbean, Japanese and Chinese background. The disease has also been considered uncommon in India until recently. Hospital records have revealed an increasing trend of the disease in predominantly wheat‐eating areas of North India. The aim of the present study was to determine the prevalence of celiac disease among school children in Punjab, North India.Methods:  The study was carried out in the Ludhiana district of Punjab, Northern India. A total of 4347 children aged 3–17 years attending different schools were enrolled. A structured questionnaire was used to collect sociodemographic data and symptoms and signs related to celiac disease and various sociodemographic factors. The screening for celiac disease for the suspected celiacs was done by testing for antitissue transglutaminase (anti‐tTG) by indirect solid‐phase immunometric assay (ELISA). All children with high anti‐tTG whose parents consented underwent upper gastrointestinal endoscopy for small bowel biopsy from the second part of the duodenum. Histopathology was expressed according to the Marsh classification of 1992. Follow up was carried out among children who were put on a gluten‐restricted diet, at monthly intervals for 3 months and every 3 months thereafter. The diagnosis of celiac disease was established on the basis of the revised European Society of Paediatric Gastroenterologists and Nutritionists (ESPGAN) criteria (confirmed cases).Results:  A total of 4347 school children (1967 girls, 2380 boys, age range 3–17 years) were screened for celiac disease. Out of these, 198 suspected children were identified for further evaluation. Twenty‐one children tested positive for anti‐tTG assay (10.6%, 95% confidence interval: 16.91–34.79). Seventeen of these 21 children agreed to undergo biopsy; of these, 14 had histological changes consistent with celiac disease and all these 14 children had clinical response to gluten restriction. Three children with high anti‐tTG had normal mucosa on duodenal biopsy and were not labelled as being in the celiac disease group. In the final analysis the disease prevalence was one in 310 children.Conclusions:  This is the first study on celiac disease prevalence among school children from India. Although this disease frequency of one in 310 is thought to be an under‐assessment, it clearly shows that celiac disease is not rare in wheat‐eating areas of North India.