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L B Ellis

Publications and source records attributed to L B Ellis.

At least 19 recordsLinked to original sources
PubMed1995

A manganese-dependent dioxygenase from Arthrobacter globiformis CM-2 belongs to the major extradiol dioxygenase family.

Almost all bacterial ring cleavage dioxygenases contain iron as the catalytic metal center. We report here the first available sequence for a manganese-dependent 3,4-dihydroxyphenylacetate (3,4-DHPA) 2,3-dioxygenase and its further characterization. This manganese-dependent extradiol dioxygenase from Arthrobacter globiformis CM-2, unlike iron-dependent extradiol dioxygenases, is not inactivated by hydrogen peroxide. Also, ferrous ions, which activate iron extradiol dioxygenases, inhibit 3,4-DHPA 2,3-dioxygenase. The gene encoding 3,4-DHPA 2,3-dioxygenase, mndD, was identified from an A. globiformis CM-2 cosmid library. mndD was subcloned as a 2.0-kb SmaI fragment in pUC18, from which manganese-dependent extradiol dioxygenase activity was expressed at high levels in Escherichia coli. The mndD open reading frame was identified by comparison with the known N-terminal amino acid sequence of purified manganese-dependent 3,4-DHPA 2,3-dioxygenase. Fourteen of 18 amino acids conserved in members of the iron-dependent extradiol dioxygenase family are also conserved in the manganese-dependent 3,4-DHPA 2,3-dioxygenase (MndD). Thus, MndD belongs to the extradiol family of dioxygenases and may share a common ancestry with the iron-dependent extradiol dioxygenases. We propose the revised consensus primary sequence (G,T,N,R)X(H,A)XXXXXXX(L,I,V,M,F)YXX(D,E,T,N,A)PX(G,P) X(2,3)E for this family. (Numbers in brackets indicate a gap of two or three residues at this point in the sequence.) The suggested common ancestry is also supported by sequence obtained from genes flanking mndD, which share significant sequence identity with xylJ and xylG from Pseudomonas putida.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Valid and invalid implementations of GOR secondary structure predictions.

GOR algorithms have long been a standard methodology for predicting protein secondary structure from primary sequence. We have developed two short validation sequences for the GOR I and GOR II algorithms. Use of these sequences with seven commercial and non-commercial implementations of these algorithms demonstrated that several were incorrect implementations, including two of the three commercial modules implementing the GOR I algorithm. This may be due to an easy misinterpretation of the GOR I algorithm and related data tables. We present the validation sequences and discuss implications of this widely propagated error on secondary and tertiary structure prediction, using several proteins of known structure in three different structural classes as examples. A valid GOR I implementation predicts secondary structure increases the accuracy of predictions by from 1-13 percentage points over an invalid implementation based on the easy misinterpretation. A valid implementation of the GOR I and GOR II algorithms is available from the authors.

Algorithms↗
PubMed1992

Identification of the three-dimensional thioredoxin motif: related structure in the ORF3 protein of the Staphylococcus aureus mer operon.

We have developed a computerized search pattern for recognition of the three-dimensional redox site of thioredoxins based on primary and predicted secondary structure. This pattern, developed in the ARIADNE protein expert system, is used to search for thioredoxin-like tertiary structural motif among proteins for which the only structural information is the primary sequence. The pattern was trained on 102 protein sequences (25 functionals and 77 controls); it matches all 25 members of the functional set under cutoff conditions that include only 2 members of the control set, for a sensitivity of 1.0 and a specificity of 0.97. The pattern matches only one of the two thioredoxin-like domains in protein disulfide isomerases (PDIs) and their analogues, suggesting that the C-terminal domain is more structurally similar to thioredoxin than the N-terminal domain. The Escherichia coli DsbA protein, a possible PDI analogue, appears to be more structurally similar to the N-terminal thioredoxin-like domain of PDIs. Thioredoxin-like redox functionality has been proposed for lutropin and follitropin, in part on the basis of their having -Cys-X-Pro-Cys- sequences. None match our pattern; all lack a predicted alpha-helix pattern element immediately after the active site. Hypothetical proteins in the National Biomedical Research Foundation Protein Identification Resource database were searched for matches to the pattern. The most interesting match was a hypothetical protein (161 residues) from the third open reading frame in the Staphylococcus aureus mer operon, which is involved in mercury detoxification. The match to our pattern and the hydrophobicity distribution in aligned elements of secondary structure not in our pattern strongly suggest that it has thioredoxin-like structure.

Amino Acid Sequence↗
PubMed1991

Knowledge gains from a computer-based health risk appraisal.

During 1990, 83 patients seen for a general physical examination at a family practice clinic completed a computer-based health risk appraisal in one of two formats, batch or interactive. They also completed a written questionnaire on their health risks and knowledge before taking the appraisal, and 65 of them completed another health risk appraisal and questionnaire three months later. No difference in user evaluation of the appraisal regarding its helpfulness, their intent to change behavior based on the appraisal, or amount learned from the appraisal was found between batch and interactive formats. About half (48%) of the individuals correctly estimated their overall health risks before taking the health risk appraisal. Among those who initially misjudged their health risks, few women adjusted their health risk rating at followup. Men showed a tendency to adjust their rating to more closely agree with the health risk appraisal estimates although the differences are not statistically significant. Eighty percent of the men and 55% of the women accurately rated their overall risk at followup. Knowledge of specific causes of death did not improve at followup.

Adult↗
PubMed1991

Use of a computer-based health risk appraisal by older adults.

BACKGROUND: A health risk appraisal (HRA) is a tool for health promotion. Conversational microcomputer-based HRAs may be more cost effective than other HRA formats. The acceptability of conversational HRAs, however, has not been demonstrated for older adults. METHODS: We studied the acceptability of a conversational microcomputer-based HRA in a sample of 247 adults at the Minnesota State Fair and the Senior Options Exposition. All users were offered the appraisal via mouse or keyboard interface. Acceptability was measured in terms of user-reported helpfulness, intent to change, time of use, and willingness to view HRA health recommendations. Data on completion time and willingness to view HRA recommendations were collected for Senior Exposition users only. Regression analyses were used to examine the combined impact of interface (mouse or keyboard), location (State Fair or Senior Exposition), age, and sex on user acceptability. Results. Interface and location had no effect on helpfulness or change ratings. Older users rated the appraisal more helpful (P less than .007). Both older and female users reported more intent to change behavior (P = .016, both). Time to use the appraisal was related to interface, age, and sex. Mouse users (P less than .0001), older users (P less than .0001) and female users (P less than .05) took significantly longer to use the appraisal. Significantly more mouse users declined to see recommendations (P less than .02). CONCLUSIONS: Older users can derive as much or more value from conversational health risk appraisals as younger users; however, a mouse interface may be less effective for this age group.

Adult↗
PubMed1988

Echocardiographic dimensions in trained and untrained 12-year-old boys and girls.

The purpose of this study was to compare echocardiographically measured left ventricular (LV) dimensions of 85 trained 11-12-year-old athletes with 106 untrained children matched for skeletal age and fat-free mass. Training status for each group applied to the 3 years prior to the measurements. It was found that 12 min and 100 m runs demonstrated the superior athletic ability of the trained children, but there were no significant differences in LV internal diameters at diastole and systole, in LV posterior wall thickness, or in LV end-diastolic volume and LV mass. These data indicate that little difference occurs in LV size between moderately trained and untrained 11-12-year olds or between boys and girls matched for fat-free mass and skeletal age. It is also evident that consistent but moderate training during late pre-adolescence has little effect on LV development.

Adipose Tissue↗
PubMed1986

Computers as learning resources in the health sciences: impact and issues.

Starting with two computer terminals in 1972, the Health Sciences Learning Resources Center of the University of Minnesota Bio-Medical Library expanded its instructional facilities to ten terminals and thirty-five microcomputers by 1985. Computer use accounted for 28% of total center circulation. The impact of these resources on health sciences curricula is described and issues related to use, support, and planning are raised and discussed. Judged by their acceptance and educational value, computers are successful health sciences learning resources at the University of Minnesota.

Computer-Assisted Instruction↗
PubMed1985

Computer-based patient education.

The increased exposure of health professionals to computers and the decreased cost of this technology make computer-based instruction an increasingly attractive alternative for patient education. This article presents an overview of the present status of computer-based patient education and suggests guidelines for the development and use of such educational materials. It emphasizes general techniques applicable to a wide range of patients and conditions and includes a list of resources available to the interested health professional.

Computer-Assisted Instruction↗
PubMed1982

A conversational microcomputer-based health risk appraisal.

We have developed a conversational microcomputer-based health risk appraisal program. This appraisal has been tested on over 200 users at 3 locations in urban and suburban Minneapolis. It was considered helpful by 92% of its users, and 25% stated that they would probably or definitely change a living habit based on its use. All 3 populations considered it comparably helpful, irrespective of their different age and sex distributions. A complex health appraisal, which was formerly assumed to require batch processing on a large computer, can be carried out on a small personal system in an interactive mode. Such a program is acceptable to users and has the potential to motivate change in risky behavior.

Adult↗
PubMed1982

Microcomputer as patient educator.

A computer-assisted lesson on general drug knowledge as a patient education tool is described. A drug I.Q. quiz is one of seven microcomputer lessons available to patients in the waiting room of an ambulatory-care clinic. The drug quiz consists of 19 multiple-choice and six true or false questions. After each question, the computer responds with a brief paragraph keyed to the answer selected by the user. If the answer for a multiple-choice question is incorrect, the user can reanswer the question before proceeding. At the end of the lesson, a score is graphically displayed and the user is asked to evaluate the lesson. The computer stores the total number of lessons completed, total scores, number of times each question was answered incorrectly on first and second attempts, number of times each question was answered a second time, and each user's responses to the quiz and evaluation questions. Based on 313 completions of the drug quiz from September 1981 through May 1982, 86% of the users stated that they learned at least something useful, and 72% liked the quiz. The mean (+/- S.D.) number of correct answers on the first attempt was 16 +/- 5; scores improved by an average of 2.5 +/- 2 by reanswering questions. Of 2421 multiple-choice questions answered incorrectly, 62% were reanswered. Of these second attempts, 52% were correct. Item validity scores indicated that the drug quiz serves as a realistic appraisal of drug knowledge. The microcomputer can be an effective medium for patient education.

Computers↗
PubMed1975

Differential posteclosion housing experiences and reproduction in Drosophila.

Differential housing following eclosion was found to affect the mating behaviour of both sexes of Drosophila melanogaster. Flies housed in isolation showed higher mating frequencies and shorter latencies than did group-housed flies. Given a choice of an isolated or group-housed male, females tended to mate with males with similar housing experiences as themselves. Given a choice of an isolated or group-housed female, males strongly preferred the former. The possibility is advanced that these effects are mediated by olfactory stimuli.

Animals↗