bluuebunny/crossref_metadata_2025_split huggingface dataset:
Short‐ and long‐term changes in proteome composition and kinetic properties in a culture of Escherichia coli during transition from glucose‐excess to glucose‐limited growth conditions in continuous culture and vice versa
Authors: Wick Lukas M. , Quadroni Manfredo , Egli Thomas 
Published: March 2003

To investigate the ability of Escherichia coli K12 MG1655 to cope with excess and limitation of a carbon and energy source, we studied the changes in kinetic properties and two‐dimensional (2D) gel protein patterns of an E. coli culture. The population was transferred from glucose‐excess batch to glucose‐limited continuous culture (D = 0.3 h−1), in which it was cultivated for 500 h (217 generations) and then transferred back to glucose‐excess batch culture. Two different stages to glucose‐limitation were recognized: a short‐term physiological adaptation characterized by a general effort in enhancing the cell's substrate scavenging ability and mutations resulting in a population exhibiting increased glucose affinity. Physiological short‐term adaptation to glucose‐limitation was achieved by upregulation of 12 proteins, namely MglB, MalE, ArgT, DppA, RbsB, YdcS, LivJ (precursor), UgpB (precursor), AceA, AldA, AtpA and GatY. Eight of these proteins are periplasmic binding proteins of ABC transporters. Most of them are not involved in glucose transport regulons, but rather in chemotaxis and transport of other substrates, whereas MalE and MglB have previously been shown to belong to transport systems important in glucose transport under glucose‐limited conditions. Evolution under low glucose concentration led to an up to 10‐fold increase in glucose affinity (from a Ks of 366 ± 36 µg l−1 at the beginning to 44 ± 7 µg l−1). The protein pattern of a ‘500‐h‐old’ continuous culture showed a highly increased expression of MglB and MalE as well as of the regulator protein MalI. When adapted cells taken from the ‘500‐h‐old’ continuous culture were transferred to batch culture, an increased expression of MalE was observed, compared with cells from un‐adapted batch‐grown cells. Otherwise, no significant changes were observed in the protein pattern of batch‐grown populations before and after 500 h of evolution in the glucose‐limited continuous culture.
Reduction of humic substances by halorespiring, sulphate‐reducing and methanogenic microorganisms
Authors: Cervantes Francisco J. , Bok Frank A. M. de , Duong‐Dac Tuan , Stams Alfons J. M. , Lettinga Gatze , Field Jim A. 
Published: March 2003

SummaryPhysiologically distinct anaerobic microorganisms were explored for their ability to oxidize different substrates with humic acids or the humic analogue, anthraquinone‐2,6‐disulphonate (AQDS), as a terminal electron acceptor. Most of the microorganisms evaluated including, for example, the halorespiring bacterium, Desulfitobacterium PCE1, the sulphate‐reducing bacterium, Desulfovibrio G11 and the methanogenic archaeon, Methanospirillum hungatei JF1, could oxidize hydrogen linked to the reduction of humic acids or AQDS. Desulfitobacterium dehalogenans and Desulfitobacterium PCE1 could also convert lactate to acetate linked to the reduction of humic substances. Humus served as a terminal electron acceptor supporting growth of Desulfitobacterium species, which may explain the recovery of these microorganisms from organic rich environments in which the presence of chlorinated pollutants or sulphite is not expected. The results suggest that the ubiquity of humus reduction found in many different environments may be as a result of the increasing number of anaerobic microorganisms, which are known to be able to reduce humic substances.
Effect of oil pollution on euendolithic cyanobacteria of the Arabian Gulf
Authors: Al‐Thukair Assad A. 
Published: March 2003

SummaryMicrobial euendoliths (true borer) cyanobacteria are carbonate‐boring microorganisms found in modern and ancient marine environments. Modern euendoliths include a wide range of prokaryotes as well as eukaryotes, which have been reported world‐wide. The importance of euendolithic cyanobacteria concerns their role in bio‐erosion of calcium carbonate substrates and as ecological indicators of shallow, tropical and subtropical marine environments. Arabian Gulf ooids from four sites along the east coast of Saudi Arabia have been bored and inhabited by several species of euendolithic cyanobacteria. This assemblage of different species exists simultaneously within the same ooid grain. Comparisons of 1989 and 1992 data reveal a drastic reduction in active euendoliths, and the average numbers of colonies in these ooids. This study reveals the harmful effect of the 1991 oil spill on these unique microorganisms residing in these ooids.
Correlation between pigmentation and antifouling compounds produced by Pseudoalteromonas tunicata
Authors: Egan Suhelen , James Sally , Holmström Carola , Kjelleberg Staffan 
Published: March 2003

Abstract Pseudoalteromonas tunicata is a marine bacterium with the ability to prevent biofouling by the production of at least four target‐specific compounds. In addition to these antifouling compounds, P. tunicata produces at least two pigments. These include a yellow and a purple pigment which, when combined, give the bacterium a dark green appearance. Transposon mutagenesis was used in this study to investigate the correlation between pigment production and the expression of specific antifouling phenotypes in P. tunicata. Four different categories of pigmentation mutants were isolated including yellow, dark‐purple, light‐purple and white mutants. The mutants were tested for their ability to inhibit the settlement of invertebrate larvae, algal spore germination, fungal growth and bacterial growth. The results showed that the yellow‐pigmented mutants retained full antifouling activity, whereas the purple and white mutant strains had lost some, or all, of their ability to inhibit target organisms. This demonstrates that the loss of antifouling capabilities correlates with the loss of yellow pigment and not purple pigment. Sequencing and analysis of the genes disrupted by the transposons in these mutants identified a number of potential biosynthetic enzymes and transport systems involved in the synthesis and regulation of pigmentation and fouling inhibitors in this organism.
Identification of complex composition, strong strain diversity and directional selection in local Pseudomonas stutzeri populations from marine sediment and soils
Authors: Sikorski Johannes , Möhle Martin , Wackernagel Wilfried 
Published: March 2003

SummaryMembers of Pseudomonas stutzeri have been isolated world‐wide from various habitats including aquatic and terrestrial ecosystems. The global population has a clonal structure, is of exceptionally high genetic diversity and has been grouped into eight genomovars. We have analysed four local populations (n = 89–125) from three geographically separated habitats (two from a marine sediment and two from different soils) by random amplified polymorphic DNA–polymerase chain reaction (RAPD‐PCR), restriction fragment length polymorphism (RFLP) of the rpoB gene and 16S rDNA sequences in order to quantify the influence of evolutionary forces on closely related groups of proliferating cells in situ. All populations consisted of a complex structure of genomic subgroups with variable numbers of members. The analyses revealed that the two populations from marine sediment were rather similar. At least three of the populations were influenced by migrational input as concluded from the presence of members from different genomovars. All populations showed very high strain diversity suggesting strong influence of mutability. Neutrality tests indicated that two or possibly three of the populations were shaped by directional selection. Thus, the local populations of P. stutzeri reflect already the high genetic diversity of the global population and are influenced, to different extents, by migration, mutation and directional selection.
Compatible solutes of organisms that live in hot saline environments
Authors: Santos Helena , Da Costa Milton S. 
Published: March 2003

SummaryThe accumulation of organic solutes is a prerequisite for osmotic adjustment of all microorganisms. Thermophilic and hyperthermophilic organisms generally accumulate very unusual compatible solutes namely, di‐myo‐inositol‐phosphate, di‐mannosyl‐di‐myo‐­inositol‐phosphate, di‐glycerol‐phosphate, mannosylglycerate and mannosylglyceramide, which have not been identified in bacteria or archaea that grow at low and moderate temperatures. There is also a growing awareness that some of these compatible solutes may have a role in the protection of cell components against thermal denaturation. Mannosylglycerate and di‐glycerol‐phosphate have been shown to protect enzymes and proteins from thermal denaturation in vitro as well, or better, than compatible solutes from mesophiles. The pathways leading to the synthesis of some of these compatible solutes from thermophiles and hyperthermophiles have been elucidated. However, large numbers of questions remain unanswered. Fundamental and applied interest in compatible ­solutes and osmotic adjustment in these organisms, drives research that, will, in the near future, allow us to understand the role of compatible solutes in osmotic protection and thermoprotection of some of the most fascinating organisms known on Earth.
Influence of the growth substrate on the mycolic acid profiles of mycobacteria
Authors: Wick Lukas Y. , Wattiau Pierre , Harms Hauke 
Published: March 2003

SummaryThe influence of growth substrates on mycolic acid profiles of PAH‐degrading Mycobacterium spp. LB501T, LB307T and VM552 was examined by high‐performance liquid chromatography (HPLC) using glucose, alkanes, polycyclic aromatic hydrocarbons (PAH) or Luria–Bertani medium (LB) as the sole carbon source. The substrates gave rise to varying mycolic acid profiles, as bacteria growing on poorly water‐soluble substrates exhibited more hydrophobic mycolic acids than cells grown on glucose. Our results indicate that mycobacteria respond to the growth substrate by changing the mycolic acid composition of their cell wall, pointing at the importance of the growth substrate for mycolic acid profiling as an identification method of actinomycetes.
Characterization of the surface hydrophobicity of filamentous fungi
Authors: Smits Theo H. M. , Wick Lukas Y. , Harms Hauke , Keel Christoph 
Published: March 2003

SummaryA method for the quantitative analysis of the hydrophobicity of the mycelial mat of filamentous fungi based on contact angle measurements is presented. It was tested for a range of fungi belonging to the classes of basidiomycetes, ascomycetes and deuteromycetes. The measured contact angles of the mycelial mats ranged between hydrophilic (<30°) for the deuteromycetes Fusarium oxysporum Fo47 GUS1 and Trichoderma harzianum P1[pZEGA1] and hydrophobic (>60°) for the ascomycete Cladosporium sp. DSE48.1b and the basidiomycetes Paxillus involutus WSL 37.7, Hebeloma crustiliniforme WSL 6.2, Suillus bovinus WSL 48.1 and Laccaria bicolor WSL 73.1. For some fungi, variations in the hydrophobicity of the mycelium depending on the growth medium, the physiological state and the exposure to water were distinguished.
Reducing the risk of stroke in diabetes: what have we learned that is new?
Authors: Sacco Ralph L. 
Published: March 2003

SummaryGiven the significant public health impact of stroke and the identification of nonmodifiable (age, gender, race/ethnicity) and modifiable (blood pressure, diabetes, lipid profile, and lifestyle) risk factors, early prevention strategies should be initiated. When a patient suffers a stroke, the focus of care becomes prevention of future events. For the patient with diabetes, comprehensive medical management of ischaemic stroke (primary or secondary prevention) includes antihypertensive and lipid‐lowering therapy, as well as antiplatelet therapy. Despite the cerebrovascular risk reduction with these modalities, clearly new agents are needed. The Heart Outcomes Prevention Evaluation (HOPE) study provides compelling evidence that treatment with the angiotensin converting enzyme inhibitor, ramipril, can further reduce the risk of stroke in high‐risk patients by mechanisms other than lowering blood pressure. In HOPE, patients were normotensive at baseline. Therefore, for the first time, in a patient population without left ventricular dysfunction, the effects of an ACE inhibitor ramipril on reducing stroke risk were demonstrated. Ramipril 10 mg achieved a significant 33% reduction in stroke among patients with diabetes. Based on the HOPE study, the recently published American Heart Association guidelines for the primary prevention of stroke recommend ramipril to prevent stroke in high‐risk patients and in patients with diabetes and hypertension. Wide‐scale adherence to these guideline recommendations for the prevention of primary and secondary stroke would significantly benefit the public health.
Distribution of newly formed vessels in human colorectal carcinomas with microangiography
Authors: Ogawa  , Miyazaki  , Tokunaga  
Published: March 2003

Objectives Together, tumour cells and blood vessels compose a highly integrated ecosystem. This study was designed to investigate the distribution of newly formed vessels and the relationship of tissue structure to vascularity in human colorectal carcinomas.Subjects and methods Microangiography, a silicone rubber compound injection method, was used successfully to study 18 resected colon cases. Vascular densities were evaluated by soft x‐ray examination, and histological constitution was assessed by an ocular, square lattice, superimposing technique.Results On average, vascular density was 1.43 times greater (range 1.02–1.80) in tumour tissue than in normal mucosa. However, the vascular density in mucinous adenocarcinomas was significantly lower than that in well and moderately differentiated adenocarcinomas. When vascular densities were compared in an upper peripheral region (UR) and a lower central region (LR) (designated as upper and lower with reference to their position in relation to the submucosal vessels), the UR showed significantly higher vascular density than the LR. Histologically, the UR had a significantly higher density of carcinoma cells than the LR.Conclusion These results suggest that the vascularity of colorectal carcinomas varies with respect to their topographical position and their histological subtypes.
Rectal bleeding in general and hospital practice; ‘the tip of the iceberg’
Authors: Thompson  , Pond  , Ellis  , Beach  , Thompson  
Published: March 2003

ObjectiveTo determine the incidence of rectal bleeding and its predictive value for cancer in the general population, patient consultation rates to GPs, referral rates to hospital and the nature of rectal bleeding from benign causes.Subjects and methodsThe study was based on a postal questionnaire in the setting of three General Practices in Portsmouth and South‐east Hampshire (two in Portsmouth, one in Petersfield). There were 6000 subjects, over the age of 16 years, randomly selected from the three General Practices. The main outcome measures were incidence of rectal bleeding with respect to age and sex, the number who sought medical advice from their GPs and the numbers referred on to hospital. The frequency of dark red bleeding, of an associated change in bowel habit and the presence or absence of anal symptoms were also determined. The prevalence of colorectal cancer was determined in subjects reporting rectal bleeding in the 5‐year period after the postal survey.ResultsSix thousand questionnaires were sent and 4006 (67%) were returned. Of the respondents 18% (709/4006) reported rectal bleeding in the previous year. Four percent (175/4006) had had bleeding for the first time and 38% (1522/4006) had bled at some time in the past. Of the 709 individuals, 512 (72%) had not consulted their GPs. Of the 197 (28%) who did, 50 (1:4, 7%) were referred to hospital. Eighteen percent (125/709) described the blood as dark red, and 88% (621/709) had anal symptoms. In 56% (394/709) the rectal bleeding was associated with a change in bowel habit mostly to hard stools (n=208), fewer to loose stools (n=98). Rectal cancer was diagnosed in only one patient 4 years after the first episode of rectal bleeding, giving a predictive value of rectal bleeding for colorectal cancer in the community of 1:709.ConclusionMany people in the community have painless rectal bleeding, an associated change in bowel habit and dark red bleeding, factors previously thought to indicate a high risk of colorectal cancer. Rectal bleeding has however a low (1:709) predictive value for cancer. As the result of a considerable selection process, only a small number are investigated in hospital. These patients therefore represent a small proportion of all patients with this symptom. The value of the factors used to decide which patients need investigation should be re‐assessed.
Impact of surgeon organization and specialization in rectal cancer outcome
Authors: García‐Granero E. , Martí‐Obiol R. , Gómez‐Barbadillo J. , García‐Armengol J. , Esclapez P. , Espí A. , Jiménez E. , Millán M. , Lledó S. 
Published: March 2003

PurposeThe present study was designed to assess the differences in the outcome of patients with rectal cancer treated by a group of surgeons before and after being organized as a Coloproctology Unit at the same University Department of Surgery.MethodsComparison of two periods of rectal cancer surgery: I (1986–91) and II (1992–95). Period I: 94 patients were operated on by 14 general surgeons. Period II: 108 patients were operated on by only 4 surgeons of the same group organized as a Colorectal Surgery Unit after visiting referral centres abroad, adopting techniques such as total mesorectal excision (TME) for middle and low rectal cancer and washout of rectal stump. Mean follow‐up during periods I and II was 69.1 and 42.0 months, respectively. A prospective data base analysis was used. Survival and local recurrence rates were calculated by the actuarial method. For comparison between groups the log rank method was used.ResultsThe two groups were comparable with respect to mean age, gender, TNM and rectal tumour location. A significant increase in radical resectability and a decrease of the Abdominoperineal resection (APR)/Low anterior resection (LAR) ratio were observed in the second period. The overall pelvic recurrence rate was 25% in the first period and 11 in the second (P < 0.01). Significant differences were also found when the patients with LAR were compared between both periods, 30% vs 9% (P < 0.01) and specially when the 10 cm anal verge distance was considered to divide the LAR groups. No differences were found regarding the APR procedures in both periods. There was improved cancer‐specific survival for the LAR group in the second period (P=0.03).ConclusionSpecialization and centralization influence the quality of rectal cancer surgery, mainly local recurrence rates and survival after low anterior resection.
Primary adenosquamous carcinoma of the rectum. Report of 4 cases and review of the literature
Authors: Schlegel R. D. , Dehni N. , Cravino A. T. , Tiret E. , Prevot S. , Waisman H. J. , Parc R. 
Published: March 2003

ObjectiveTo review the experience of two referral centres in the management of an infrequent condition: primary adenosquamous carcinoma of the rectum, a rare disease.Materials and methodsFour cases of primary adenosquamous carcinomas of the rectum are reported with a review of the literature. No preoperative diagnosis of adenosquamous carcinoma was established. All tumours were located in the rectum. Two patients presented with liver metastasis. No preoperative therapies were indicated. All patients underwent surgery.ResultsPatients underwent anterior resections (n=2), recto‐sigmoid resection (n=1) and abdomino‐perineal excision (n=1). All resected specimens had positive lymph nodes and metastatic liver disease was confirmed in the two cases. No adjuvant therapy was carried out after surgery and patients died within 8 months after surgical treatment.ConclusionsAdenosquamous carcinoma of the rectum is a rare and aggressive tumour characterized by coexisting of malignant glandular and squamous components. Presentation is usually at an advanced stage. The tumour is aggressive and metastatic disease at the time of diagnosis is common. Surgery is the treatment of choice. Adjuvant therapy is difficult to evaluate prospectively due to the rarity of the condition. Survival is less than 50% than that for adenocarcinoma.
Preliminary evaluation of United Kingdom National Referral Guidelines for lower gastrointestinal tract cancer
Authors: Mahon C. C. W. , Vaizey C. J. , Taylor I. , Boulos P. B. 
Published: March 2003

ObjectiveTo evaluate the efficiency of the criteria proposed by the National Referral Guidelines at selecting patients with lower gastrointestinal tract cancer for urgent outpatient assessment when compared with the standard method for prioritization.Patients and methodsConsecutive patients aged 50 and over referred to a colorectal unit were offered urgent or non‐urgent outpatient appointments on the basis of the contents of the referral letter. Clinical information obtained during the outpatient consultation was used to identify those patients that satisfied the guideline criteria for urgent referral. Patients were investigated and the findings recorded.ResultsOf 247 patients who completed their investigations 18 were found to have lower gastrointestinal tract cancer. Urgent outpatient appointments were offered to 115 patients of whom 14 had cancer (P = 0.0067, sensitivity=78%). A total of 119 patients satisfied the guideline criteria for urgent referral, including 17 of the patients who were found to have cancer (P < 0.0001, sensitivity=94%).ConclusionThe criteria used in the guidelines provide an effective method for selecting patients with cancer for urgent assessment. Application of the guidelines by general practitioners can be recommended.
Flexible sigmoidoscopy in general practice
Authors: Vellacott K. D. , Clarke D. , Beech C. , Joshi H. 
Published: March 2003

ObjectiveFlexible sigmoidoscopy (FS) is increasingly being accepted as the method of choice for initial investigation of rectal bleeding and other lower gastrointestinal symptoms. The aim of this study was to assess the feasibility of FS in general practice and to compare the yield, cost and efficiency of a service provided by a consultant surgeon and a General Practitioner (GP).Subjects and methodsA prospective study of FS was undertaken on 430 unsedated patients with symptoms suggestive of lower bowel disease in two general practices.ResultsThe yield was comparable to hospital based data. Fifteen (3.5%) cancers were detected, of which 40% were Dukes A, and 46 (10.7%) adenomatous polyps. Cost per patient examination by a GP including capital costs, depreciation of equipment, and training was calculated to be cheaper or at least equivalent to a hospital‐based service but inefficient due to the low numbers examined per month. There were no complications and no missed cancers after a minimum follow up of 2 years.ConclusionsThe results suggest that FS can be safely performed by a suitably trained GP in health centres, but better utilization of equipment and value for money would be obtained by providing the service for a group of practices rather than a single practice as in this study.