bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcriptional regulation of the agr locus and the identification of DNA binding residues of the global regulatory protein SarR in Staphylococcus aureus
Authors: Manna Adhar C. , Cheung Ambrose L. 
Published: April 2006

SummaryMany members of the transcriptional regulator SarA protein family are winged‐helix proteins that are involved in gene regulation essential to Staphylococcus aureus pathogenesis. Investigation of the mechanism by which this family of genes acts at the molecular level will likely contribute to the understanding of the pathogenesis process and enhance the potential for the development of inhibitors capable of controlling S. aureus infections. Our previously published studies demonstrate that SarR is a repressor of sarA expression. Here, we show that SarR (a member of the SarA protein family) in part regulates agr expression by direct binding to the agr intergenic promoter region as determined by gel shift and DNase I footprinting assays. Analysis of the double sarA/sarR mutant in the early phase of growth reveals its significant role in regulating agr expression as compared with single mutants. Based on the previously reported crystal structure of SarR, we conducted site‐specific mutagenesis and demonstrate that K52 residues within helix–turn–helix (HTH), K80, R82 and R88 (in the wing) and L105 (in the α5 helix) are important for DNA binding. Interestingly, SarR and SarA binding sites on the agr promoter are confined within the same region of DNA. Additional gel shift studies with SarR and SarA suggest that these two proteins may bind the same region of the agr promoter.
High expression in leaves of the zinc hyperaccumulator Arabidopsis halleri of AhMHX, a homolog of an Arabidopsis thaliana vacuolar metal/proton exchanger
Authors: ELBAZ BENAYAHU , SHOSHANI‐KNAANI NOA , DAVID‐ASSAEL ORA , MIZRACHY‐DAGRI TALYA , MIZRAHI KEREN , SAUL HELEN , BROOK EMIL , BEREZIN IRINA , SHAUL ORIT 
Published: April 2006

ABSTRACTZn hyperaccumulator plants sequester Zn into their shoot vacuoles. To date, the only transporters implicated in Zn sequestration into the vacuoles of hyperaccumulator plants are cation diffusion facilitators (CDFs). We investigated the expression in Arabidopsis halleri of a homolog of AtMHX, an A. thaliana tonoplast transporter that exchanges protons with Mg, Zn and Fe ions. A. halleri has a single copy of a homologous gene, encoding a protein that shares 98% sequence identity with AtMHX. Western blot analysis with vacuolar‐enriched membrane fractions suggests localization of AhMHX in the tonoplast. The levels of MHX proteins are much higher in leaves of A. halleri than in leaves of the non‐accumulator plant A. thaliana. At the same time, the levels of MHX transcripts are similar in leaves of the two species. This suggests that the difference in MHX levels is regulated at the post‐transcriptional level. In vitro translation studies indicated that the difference between AhMHX and AtMHX expression is not likely to result from the variations in the sequence of their 5′ untranslated regions (5′UTRs). The high expression of AhMHX in A. halleri leaves is constitutive and not significantly affected by the metal status of the plants. In both species, MHX transcript levels are higher in leaves than in roots, but the difference is higher in A. halleri. Metal sequestration into root vacuoles was suggested to inhibit hyperaccumulation in the shoot. Our data implicate AhMHX as a candidate gene in metal accumulation or tolerance in A. halleri.
Molecular characterization of Erwinia amylovora strains from different host plants through RFLP analysis and sequencing of hrpN and dspA/E genes
Authors: Giorgi S. , Scortichini M. 
Published: April 2006

A total of 73 Erwinia amylovora strains obtained from 13 Maloideae host species and from Rubus spp., and isolated from different geographic areas, were assessed using RFLP and DNA sequencing analysis of the 3′hrpN gene and/or of a fragment of 1341 bp of the dspA/E region. An Erwinia pyrifoliae strain, used as outgroup, was checked in the same way. For the three strains isolated from Rubus spp. and for one strain from Amelanchier sp., RFLP analysis of the hrpN gene using the RsaI enzyme yielded a PCR product 60 bp smaller than that of all the other strains. Sequence analysis of the gene revealed this was due to the absence of a 60 bp fragment in the noncoding region downstream of the gene. The strain PD 2915, isolated from Amelanchier sp. grown in Canada, showed five same‐sense substitutions and one missense substitution at position 868 of the hrpN gene, converting aspartic acid into asparagine. Also, restriction analysis of a fragment of 613 bp of the dspA/E region with CfoI revealed an RFLP pattern suitable for differentiating the E. amylovora strains isolated from Rubus spp. and Amelanchier sp. from all the others. In the dspA/E coding region, the four strains showed 13–14 missense point mutations, in some cases yielding drastic amino acid substitutions. In addition, partial sequencing of the dspA/E region of PD 2915 from Amelanchier sp. indicated a higher similarity to E. amylovora strains isolated from Rubus spp. than towards strains from other Maloideae hosts. The E. pyrifoliae strain showed 23 single nucleotide substitutions along the hrpN gene and 88% of nucleotide identity with E. amylovora strains in the portion of dspA/E region. Artificial inoculations on immature pear fruits and young shoots of Maloideae and Ruboideae showed a restricted pathogenicity for the strains from Rubus and Amelanchier, with the latter inciting blight symptoms only on Amelanchier.
Genetic diversity of Claviceps africana on sorghum and Hyparrhenia
Authors: Pažoutová S. , Frederickson D. E. 
Published: April 2006

RAPD markers were used to survey genetic variability among 140 isolates of Claviceps africana collected from Southern Africa, India, Thailand, Australia and the Americas in 1992–2002. Amplified fragment length polymorphisms were determined for a subset of the isolates. Both markers gave similar results in phenetic analysis of genetic distances between haplotypes of different geographical origin. In the Americas, a single RAPD haplotype was found throughout the various countries. The Eastern lineage consisted of two close haplotypes (one from India, the other from Thailand and Australia). Among five specialized isolates of C. africana from the alternative hosts (Hyparrhenia spp.), three haplotypes were found. Eleven private alleles distinguished the Hyparrhenia population from that on sorghum. rDNA sequences of sorghum and Hyparrhenia isolates differed in three positions. The African sorghum population of C. africana consisted of 10, mostly closely related haplotypes. Low genotypic diversity (HE = 0·0337) and the fact that most of the variation originated from between populations (GST = 0·866) suggested founder effects following recent invasion. In Southern Africa, no significant differentiation was found among six populations. Therefore the data were pooled and tested for prevalence of clonal or sexual reproduction. The presence of the over‐represented, widespread RAPD haplotype A; gametic disequilibrium (37% loci detected by exact tests); index of association (IA) significantly >0; and the high proportion of compatible loci (in the clone‐corrected and total data sets found to be 94 and 99%, respectively) support the hypothesis of clonality as the predominant means of reproduction.
A transglucosidase necessary for starch degradation and maltose metabolism in leaves at night acts on cytosolic heteroglycans (SHG)
Authors: Fettke Joerg , Chia Tansy , Eckermann Nora , Smith Alison , Steup Martin 
Published: April 2006

SummaryThe recently characterized cytosolic transglucosidase DPE2 (EC 2.4.1.25) is essential for the cytosolic metabolism of maltose, an intermediate on the pathway by which starch is converted to sucrose at night. In in vitro assays, the enzyme utilizes glycogen as a glucosyl acceptor but the in vivo acceptor molecules remained unknown. In this communication we present evidence that DPE2 acts on the recently identified cytosolic water‐soluble heteroglycans (SHG) as does the cytosolic phosphorylase (EC 2.4.1.1) isoform. By using in vitro two‐step 14C labeling assays we demonstrate that the two transferases can utilize the same acceptor sites of the SHG. Cytosolic heteroglycans from a DPE2‐deficient Arabidopsis mutant were characterized. Compared with the wild type the glucose content of the heteroglycans was increased. Most of the additional glucosyl residues were found in the outer chains of SHG that are released by an endo‐α‐arabinanase (EC 3.2.1.99). Additional starch‐related mutants were characterized for further analysis of the increased glucosyl content. Based on these data, the cytosolic metabolism of starch‐derived carbohydrates is discussed.
Differentiating enterocutaneous fistulae from suture abscesses complicating Crohn’s disease using oral administration of indocyanine green
Authors: Sou Suketo , Matsui Toshiyuki , Yao Tsuneyoshi , Naito Miki , Yorioka Makoto , Beppu Takahiro , Nagahama Takashi , Futami Kitaro 
Published: April 2006

AbstractBackground and Aim:  Clinicians encounter difficulties distinguishing enterocutaneous fistulae from postoperative suture abscesses solely by diagnostic imaging in patients with Crohn’s disease. The aim of this study was to examine whether use of intraintestinal administration of indocyanine green (ICG) could differentiate the conditions.Methods:  Twenty‐four patients with Crohn’s disease and a possible enterocutaneous fistula at the abdominal wall based on manifestations of pus drainage and exudate were enrolled. A positive test was defined by macroscopic confirmation of staining by ICG dye, which had been administered orally, on the gauze dressing applied to the lesion site.Results:  Positive responses occurred in 16 of the 24 patients. In 13 of the 16 positive patients, a fistulous communication between the lesion and the gastrointestinal tract was documented by either surgery or X‐ray examination. In the remaining three, fistulae were completely closed after administration of infliximab. The positive predictive value of the oral ICG test was 16/16 (100%). Six of the eight negative oral ICG test patients (75%) had subcutaneous (silk‐suture) abscesses that were easily closed following fistulotomy. The other two patients had fistulas confirmed either by surgery or fistulography, indicating a false negative response from the oral ICG test. The negative predictive value of the oral ICG test was 6/8 (75%); thus, the ability of the oral ICG test to correctly diagnose was 22/24 (92%).Conclusions:  This oral ICG test offers a suitable methodology for those patients possessing an occult fistulous lesion at an early stage, and where a differential diagnosis is difficult using diagnostic imaging.
Intrafamilial prevalence of hepatitis B virus in Western Brazilian Amazon region: Epidemiologic and biomolecular study
Authors: Lobato Cirley , Tavares‐Neto José , Rios‐Leite Márcio , Trepo Christian , Vitvitski Ludmila , Parvaz Parviz , Zoulim Fabien , D’Oliveira Argemiro , Paraná Raymundo 
Published: April 2006

AbstractBackground:  Hepatitis B is endemic in the Amazon region.Methods:  Serological markers for hepatitis B virus (HBV) were determined in 266 household members for hepatitis B surface antigen (HBsAg)‐positive women (G1) and 395 household members for HBsAg‐negative women (G2), randomly selected in Acre State Women’s Medical Care Program, in order to evaluate the prevalence of HBV in this population. Before blood sample collection an epidemiological questionnaire was applied.Results:  The overall prevalence of HBV carriers (HBsAg) and exposed individuals (anti‐HBc, IgG) was, respectively, 21.1% and 60.5% in G1 and 2.8% and 27.4% in G2 (P < 0.0000001). The frequency of HBsAg was higher among siblings from group G1 (75%) compared to the absence of any HBsAg‐positive sibling in G2 (P < 0.00006). The HBV markers in other family members was as follows: G1 parents, 27.3% vs 4.5% (P < 0.03), sexual partners, 21.1% vs 2.5% (P < 0.04), and offspring, 10.4% vs 1.5% (P < 0.04). A low prevalence of HBsAg and anti‐HBc (IgG) was observed for the last offspring of G2 mothers compared to the high prevalence among children of G1 mothers (0% vs 18.2%, P < 0.01 and 2.3% vs 59.1%, P < 0.0000005, respectively), with children younger than 1 year being the most affected. The frequency of the habit of sharing toothbrushes and the presence of at least one HBsAg carrier were higher in G1 than in G2 (P < 0.0001 and P < 0.000002), respectively. Genotypes A, D and G were found to be predominant by Innolipa test. There were cases that reacted to more than one genotype.Conclusion:  Intrafamilial transmission of HBV is evident in the present study and is possibly associated with the presence of more than one HBV carrier in the family and the shared use of toothbrushes among household contacts. Genotype analysis confirms intrafamilial transmission.
Detrimental effects of nitric oxide inhibition on hepatic encephalopathy in rats with thioacetamide‐induced fulminant hepatic failure: Role of nitric oxide synthase isoforms
Authors: Chu Chi‐Jen , Chang Ching‐Chih , Wang Teh‐Fang , Lee Fa‐Yauh , Chang Full‐Young , Chen Yi‐Chou , Chan Che‐Chang , Huang Hui‐Chun , Wang Sun‐Sang , Lee Shou‐Dong 
Published: April 2006

AbstractBackground:  Hepatic encephalopathy is a complex neuropsychiatric syndrome. A previous study showed that chronic nitric oxide (NO) inhibition aggravated the severity of encephalopathy in thioacetamide (TAA)‐treated rats. The present study investigated the relative contribution of NO synthase (NOS) isoforms on the severity of hepatic encephalopathy in TAA‐treated rats.Method:  Fulminant hepatic failure was induced in male Sprague‐Dawley rats by intraperitoneal injection of TAA (350 mg/kg/day) for 3 days. Rats were divided into three groups to receive Nω‐nitro‐L‐arginine methyl ester (L‐NAME, a non‐selective NOS inhibitor, 25 mg/kg/day in tap water), L‐canavanine (an inducible NOS inhibitor, 100 mg/kg/day via intraperitoneal injection) or normal saline (N/S) from 2 days prior to TAA administration and lasting for 5 days. Severity of encephalopathy was assessed by the counts of motor activity. Plasma levels of tumor necrosis factor‐α (TNF‐ α) were determined by enzyme‐linked immunosorbent assay (ELISA), and total bilirubin, alanine aminotransferase (ALT) and creatinine were determined by colorimetric assay.Results:  Compared with L‐canavanine or N/S‐treated rats (0% and 4%, respectively), the mortality rate was significantly higher in rats receiving L‐NAME administration (29%, P < 0.005). Inhibition of NO created detrimental effects on the counts of motor activities (P < 0.05). Rats treated with L‐NAME had significantly higher plasma levels of total bilirubin, ALT, creatinine and TNF‐ α as compared with rats treated with L‐canavanine or N/S (P < 0.01).Conclusion:  Chronic L‐NAME administration, but not L‐canavanine, had detrimental effects on the severity of hepatic damage and motor activities in TAA‐treated rats. These results suggest that constitutive NOS activities play a major protective role in rats with fulminant hepatic failure.
Necrolytic acral erythema in Egyptian patients with hepatitis C virus infection
Authors: El‐Ghandour Tarek M , Sakr Mohammad A , El‐Sebai Hatem , El‐Gammal Tarek F , El‐Sayed Manal H 
Published: April 2006

AbstractBackground:  Necrolytic acral erythema (NAE) is a distinctive skin lesion that was first described in 1996 with only few cases being reported, mostly from Egypt. It is unique in its acral distribution and exclusive association with hepatitis C virus (HCV) infection.Methods:  Twenty‐three patients (mean age 41.7 ± 11.5 years; M : F 10:13) with clinical features consistent with NAE were enrolled in a 3‐year period. Five of those were known HCV‐infected individuals and 18 were referred by the dermatologist for evaluation and HCV screening. Liver function tests, serum zinc, hepatitis B markers, HCV antibodies and HCV‐RNA were tested. All patients were subjected to skin biopsy examination; five lesional biopsies were selected for electron microscopic examination and capillary endothelium was scanned for hepatitis C viral particles. An additional five patients were subjected to detection of HCV‐RNA in their skin biopsies by polymerase chain reaction. All patients received oral zinc sulfate supplementation while interferon‐α therapy combined with ribavirin was available for four patients.Results:  Most NAE patients were adults (91.3%) and the skin lesions were predominantly chronic (78.3%), with affection of the dorsa of toes and/or feet in all cases. Skin biopsies showed hyperkeratosis, psoriasiform epidermis and upper epidermal necrosis. Electron microscope examination demonstrated clumped tonofilaments in the keratinocytes, yet HCV‐RNA could not be detected in the skin lesions of examined cases. Interferon‐α combined with ribavirin caused regression of skin lesions in three patients and complete clearance in one patient. Some improvement was induced by oral zinc administration.Conclusion:  Necrolytic acral erythema is considered to be a cutaneous marker for HCV infection. The majority of patients are diagnosed by dermatologists. Therefore, improved awareness of this cutaneous lesion should prompt early diagnosis and treatment of HCV, which should in turn cure the lesion and prevent progression of liver disease.
Clinical implications of C‐kit gene mutation in patients with large gastrointestinal stromal tumors
Authors: Lin Shee‐Chan , Liu Chien‐Liang , Wang Tzang‐In , Chang Wen‐Shiung , Tzen Chin‐Yuan , Huang Ming‐Jer 
Published: April 2006

AbstractBackground and Aim:  To evaluate the clinical implications of C‐kit gene mutation in patients with gastrointestinal stromal tumors (GIST) greater than 10 cm in size.Methods:  All cases of pathologically diagnosed GIST with positive CD117 immunostaining from one hospital were retrospectively reviewed. Tissue from the 25 patients with tumors greater than 10 cm in diameter were collected and DNA was extracted. Exons 9, 11, and 13 of the C‐kit gene were analyzed and the mutations compared with the clinical and pathological characteristics of the corresponding tumors.Results:  Of the 25 tumors studied, 16 had C‐kit gene mutations and nine did not. Of the 16 with mutations, there were four with exon 9 mutations, 12 with exon 11 mutations, and none with exon 13 mutations. Gene mutations were more frequent in male than female patients (12/13, 92%vs 4/12, 33%). There were no significant differences in age, resectability, recurrence rate, tumor characteristics (ulceration, necrosis, hemorrhage and mitotic counts), or survival in patients with or without gene mutations.Conclusions:  C‐kit gene mutations were frequently found in patients with large GIST, more commonly in men than in women. However, the presence of a mutation was not predictive of prognosis in patients with large GIST.
Relationship between biomarker expression and allelic alteration in esophageal carcinoma
Authors: Vegh Irene , De‐La‐Calle Santiuste Angel , Colina Francisco , Bor Lázsló , Bermejo Clara , Aragón Ana , Morán‐Jiménez María‐José , Gómez‐Cámara Agustín , De Salamanca Rafael Enríquez , Moreno‐González Enrique 
Published: April 2006

AbstractBackground and Aim:  Expression of biomarkers and probable allelic alterations were studied in esophagus tissue samples from patients with esophageal carcinoma.Methods:  A total of 116 esophagus tissue samples were obtained from 25 patients with esophagus cancer. Histological studies revealed 23 samples were adenocarcinoma and 14 samples were epidermoid carcinoma while 79 samples were non‐tumor. Expression of biomarkers was determined by enzyme immunoassay, and allelic alterations on chromosome 17p were performed by polymerase chain reaction (PCR) using primers D17S513 and D17S514.Results:  The adenocarcinoma group exhibited an increase of matrix metalloproteinase (MMP)‐1 (P < 0.0001) and sialyl Le (a) (P < 0.001) mean levels when compared with the non‐tumor group. Adenocarcinoma samples from patients with more than three positive lymph nodes had lower levels of tissue‐inhibitor metalloproteinase (TIMP)‐1 than those with negative nodes (P < 0.0005). Positive allelic alteration was associated with high levels of MMP‐1 expression (P = 0.003). Epidermoid carcinoma samples showed higher expression of MMP‐1 (P < 0.0001) and TIMP‐1 (P < 0.02) than non‐tumor samples. Both epidermal growth factor receptor and sialyl Le (a) levels were overexpressed in tumors of patients with more than three positive lymph nodes (P < 0.005). Carcinoembryonic antigen levels were higher in tumors associated with allelic wild type group (P = 0.0001) and patients with negative lymph nodes (P < 0.05). Furthermore, variability in expression of biomarkers was observed according to sample location, and allelic alterations were also found both in tumor and in some non‐tumor samples.Conclusion:  The data suggest that overexpression of tissue biomarkers associated with allelic alterations may have potential prognostic implications with different behavior in esophagus cancer.
Association between interleukin‐1 gene polymorphisms and Helicobacter pylori infection in gastric carcinogenesis in a Chinese population
Authors: Li Chun , Xia Harry Hua‐Xiang , Xie Wei , Hu Zhengguo , Ye Mei , Li Jin , Cheng Hong , Zhang Xiaolian , Xia Bing 
Published: April 2006

AbstractBackground and Aim:  Helicobacter pylori is a major cause of chronic gastritis and peptic ulcer disease and a definite carcinogen for gastric adenocarcinoma. However, the underlying pathogenic mechanisms are not fully understood. Interleukin‐1 (IL‐1) is a key cytokine involved in H. pylori‐induced gastric inflammation. The present study aimed to determine polymorphisms of IL‐1B and IL‐1 receptor antagonist (IL‐1RN) genes and their association with H. pylori infection and gastroduodenal diseases in Chinese patients.Methods:  Three hundred and ninety‐nine patients with gastroduodenal diseases (129 chronic gastritis, 127 duodenal ulcer and 143 non‐cardiac gastric cancer) and 264 healthy controls were genotyped for IL‐1B‐511 and IL‐1RN gene polymorphisms by the PCR‐RFLP method. H. pylori infection status was determined by a validated serological test.Results:  The frequency of IL‐1B‐511 T allele was significantly higher in H. pylori positive patients with non‐cardiac gastric cancer than in both H. pylori negative patients with non‐cardiac gastric cancer (60%vs 46%, P = 0.0342, OR = 1.666, 95% confidence interval [CI]: 1.045–2.656) and in healthy controls (60%vs 48%, P = 0.0071, OR = 1.665, 95%CI: 1.149–2.412). However, the polymorphism was not associated with chronic gastritis and duodenal ulcer. Multivariate logistic regression analyses identified that IL‐1B‐511 T/T carrier status was an independent risk factor for non‐cardiac gastric cancer in the presence of H. pylori infection (adjusted OR = 3.01, 95%CI: 1.27–7.11, P = 0.01), and the frequency of IL‐1B‐511 T allele was an increased risk factor for developing gastric cancer (P = 0.03, adjusted OR = 2.29, 95%CI: 1.08–4.86). There was no association between IL‐1RN gene polymorphisms and H. pylori infection and other gastroduodenal diseases.Conclusion:  IL‐1B‐511 T allele is associated with H. pylori infection in non‐cardiac gastric cancer in a Chinese population. The IL‐1B‐511 gene polymorphism appears to play an important role in gastric carcinogenesis in Chinese patients with H. pylori infection.