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The Criticism Management System for the Cochrane Library.

In April 1997, the Cochrane Collaboration implemented the Criticism Management System for The Cochrane Library, allowing readers to electronically submit criticisms on Cochrane reviews and protocols. As a result of resource constraints and user feedback, the Criticism Management System evolved through three different versions. Major problems have included difficult access to the system, a lack of automation within the system, a low number of submissions (171 criticisms submitted per 1,388 reviews), and a low response rate to these criticisms by authors of reviews (26 criticisms have received published responses). These low figures suggest that users of The Cochrane Library are not commenting on the published reviews or not using the Criticism Management System to make their criticisms known to the authors. An easier-to-use system and better ways of encouraging feedback from readers and responses from reviewers are needed in the future.

Databases, Bibliographic↗

Automated main-chain model building by template matching and iterative fragment extension.

An algorithm for the automated macromolecular model building of polypeptide backbones is described. The procedure is hierarchical. In the initial stages, many overlapping polypeptide fragments are built. In subsequent stages, the fragments are extended and then connected. Identification of the locations of helical and beta-strand regions is carried out by FFT-based template matching. Fragment libraries of helices and beta-strands from refined protein structures are then positioned at the potential locations of helices and strands and the longest segments that fit the electron-density map are chosen. The helices and strands are then extended using fragment libraries consisting of sequences three amino acids long derived from refined protein structures. The resulting segments of polypeptide chain are then connected by choosing those which overlap at two or more C(alpha) positions. The fully automated procedure has been implemented in RESOLVE and is capable of model building at resolutions as low as 3.5 A. The algorithm is useful for building a preliminary main-chain model that can serve as a basis for refinement and side-chain addition.

Algorithms↗

DNA sequencing: modular primers for automated walking.

Here we describe our progress in the development of the technology of DNA sequencing by primer walking based on the modular primer approach, which eliminates the primer synthesis bottleneck. Modular primers are assembled from 5-mers, 6-mers, or 7-mers selected from a presynthesized library of as few as 1000 oligonucleotides. This technology is expected to reduce the time per walk by a factor of 20 to 50, and the cost of DNA sequencing by a factor of 5 to 15. Both time and expense will be saved not only on the primer synthesis per se but, more importantly, as a result of the closed-end automation of the complete cycle of walking sequencing, where no human intervention will be required between the walks. Such closed-end automation has until now been precluded due to the need to synthesize a new primer for each walk. As a part of the closed cycle automation development, this report deals with modular primers used for sequencing with fluorescent dye terminators. The success rate and the quality of automated sequencing with modular primers are found similar to those with the conventional 17-20-base-long primers. One of the advantages of the described technique is simple purification without any proteins that need to be removed.

Base Sequence↗

Backbone-dependent rotamer library for proteins. Application to side-chain prediction.

A backbone-dependent rotamer library for amino acid side-chains is developed and used for constructing protein side-chain conformations from the main-chain co-ordinates. The rotamer library is obtained from 132 protein chains in the Brookhaven Protein Database. A grid of 20 degrees by 20 degrees blocks for the main-chain angles phi, psi is used in the rotamer library. Significant correlations are found between side-chain dihedral angle probabilities and backbone phi, psi values. These probabilities are used to place the side-chains on the known backbone in test applications for six proteins for which high-resolution crystal structures are available. A minimization scheme is used to reorient side-chains that conflict with the backbone or other side-chains after the initial placement. The initial placement yields 59% of both chi 1 and chi 2 values in the correct position (to within 40 degrees) for thermolysin to 81% for crambin. After refinement the values range from 61% (lysozyme) to 89% (crambin). It is evident from the results that a single protein does not adequately test a prediction scheme. The computation time required by the method scales linearly with the number of side-chains. An initial prediction from the library takes only a few seconds of computer time, while the iterative refinement takes on the order of hours. The method is automated and can easily be applied to aid experimental side-chain determinations and homology modeling. The high degree of correlation between backbone and side-chain conformations may introduce a simplification in the protein folding process by reducing the available conformational space.

Amino Acid Sequence↗

Sequencing of megabase plus DNA by hybridization: theory of the method.

A mismatch-free hybridization of oligonucleotides containing from 11 to 20 monomers to unknown DNA represents, in essence, a sequencing of a complementary target. Realizing this, we have used probability calculations and, in part, computer simulations to estimate the types and numbers of oligonucleotides that would have to be synthesized in order to sequence a megabase plus segment of DNA. We estimate that 95,000 specific mixes of 11-mers, mainly of the 5'(A,T,C,G)(A,T,C,G)N8(A,T,C,G)3' type, hybridized consecutively to dot blots of cloned genomic DNA fragments would provide primary data for the sequence assembly. An optimal mixture of representative libraries in M13 vector, having inserts of (i) 7 kb, (ii) 0.5 kb genomic fragments randomly ligated in up to 10-kb inserts, and (iii) tandem "jumping" fragments 100 kb apart in the genome, will be needed. To sequence each million base pairs of DNA, one would need hybridization data from about 2100 separate hybridization sample dots. Inevitable gaps and uncertainties in alignment of sequenced fragments arising from nonrandom or repetitive sequence organization of complex genomes and difficulties in cloning "poisonous" sequences in Escherichia coli, inherent to large sequencing by any method, have been considered and minimized by choice of libraries and number of subclones used for hybridization. Because it is based on simpler biochemical procedures, our method is inherently easier to automate than existing sequencing methods. The sequence can be derived from simple primary data only by extensive computing. Phased experimental tests and computer simulations increasing in complexity are needed before accurate estimates can be made in terms of cost and speed of sequencing by the new approach. Nevertheless, sequencing by hybridization should show advantages over existing methods because of the inherent redundancy and parallelism in its data gathering.

Algorithms↗

Identification of pediococci by ribotyping.

Pediococci are among the most prevalent microbial contaminants in breweries and they can cause ropiness and the accumulation of high levels of diacetyl in beer. The accurate identification of pediococci is important, because different species do not possess equal spoilage potential. In this study, 18 Pediococcus strains, mainly of brewery origin, were first identified using phenotypical characterization (API 50 CHL and SDS-PAGE profiling), and then ribotyped using a RiboPrinterR System. Six Pediococcus type strains and three other Pediococcus strains were used as references. Ribotyping showed higher discriminative capacity than phenotypical identification methods. Strains could be identified to species level and in many cases, differentiated even at strain level using this genetic fingerprinting method. The identifications performed by ribotyping were confirmed by 16S rDNA sequencing of selected strains. Automated ribotyping was found to be a rapid and reliable method for identifying pediococci, but requires the construction of a comprehensive fingerprint library.

Bacterial Typing Techniques↗

Reflective Evaluation of Next-Generation Sequencing Data during Early Phase Detection of the Delta Variant.

During the SARS-CoV-2 pandemic, next-generation sequencing (NGS) technologies like the Ion Torrent S5 and Illumina MiSeq, alongside advanced software, improved genomic surveillance in South Africa. This study analysed anonymized samples from the Eastern Cape using Genome Detective and NextClade, showing Ion Torrent S5 and Illumina MiSeq success rates of 96% and 94%, respectively. The study focused on genomic coverage (above 80%) and mutation detection (below 100), with the Ion Torrent S5 achieving 99% coverage compared to Illumina MiSeq's 80%, likely due to different primers used in amplification. The Ion Torrent S5 was more effective in sequencing varied viral loads, whereas Illumina MiSeq had difficulties with lower loads. Both platforms were adept at identifying clades, successfully differentiating between Beta (<45%) and Delta variants (<30%), despite minor discrepancies in assignments due to Illumina MiSeq's lower coverage, leading to a failure rate of up to 6%. Manual library preparation showed similar sample processing and clade identification capabilities for both platforms. However, differences in sequencing duration (3.5 vs. 36 hours), automation level, genomic coverage (80% vs. 99%), and viral load compatibility were noted, highlighting each platform's unique advantages and challenges in SARS-CoV-2 genomic surveillance. In conclusion, the Illumina MiSeq and Ion Torrent S5 platforms are both efficacious in executing whole-genome sequencing (WGS) via amplicons, facilitating precise, accurate, and high-throughput examinations of SARS-CoV-2 viral genomes. However, it is important to note the existence of disparities in the quality of data produced by each platform. Each system offers unique benefits and limitations, rendering them viable choices for the genomic surveillance of SARS-CoV-2.

Illumina MiSeq↗

Application of in situ PCR to yeast cells for screening YAC libraries.

We have used in situ PCR technology in yeast cells with the ultimate goal of cloning and screening genomic yeast artificial chromosome (YAC) libraries. The target sequences in YAC clones were amplified "in situ" in yeast cells by the same set of microsatellite primers used in solution-based PCR screening. The method is fast and sensitive and obviates the steps required for individual isolation of DNAs from hundreds to thousands of YAC clones and thus has an advantage over conventional solution-based PCR screening. This approach can conceivably be applied to the products of automated robotic workstations.

Animals↗

Fluorescence imaging of mobility shifts: an expression cloning method for identification of cell signaling targets.

There is a need for a simple global approach to identify signaling targets that are posttranslationally modified in response to physiologic or pathologic stimuli within living cells. Reported here is a simple method, fluorescence imaging of mobility shifts (FIMS), which relies on in-gel detection of cell-expressed green fluorescent protein fusion proteins undergoing electrophoretic mobility shifts. This detection method is applied to a small pool cDNA library screening protocol. The readout is essentially a differential display of posttranslational modifications. Unlike biochemical approaches to identifying signaling targets, the screen is performed in living cells using standard methods for transient transfection. This enables detection of intracellular targets modified in response to either molecularly defined stimuli, such as growth factors or drugs, or complex pathologic stimuli, such as oxidative stress or hypoglycemia. FIMS is rapid, sensitive, inexpensive, and nonradioactive and easily adapted to automated high throughput methods, including capillary electrophoresis. The technique is sufficiently sensitive to easily detect fluorescent proteins expressed in a single well in 384-well format. FIMS is applicable to traditional cDNA library screening, but the method will be especially attractive for screening preselected collections of autofluorescent fusion proteins. A bonus of the technique is that examination of transfected cells by fluorescence microscopy provides immediate information about intracellular localization and stimulus-induced translocation of putative targets. We illustrate the utility of the technique with pilot screens for apoptotic and mitogenic targets modified by staurosporine and serum stimulation, respectively.

Animals↗

The wavelet transform as a tool for recognition of biosignals.

The use of the wavelet transform as a signal analysis tool has been demonstrated by its successful application to the study of various signals. The first step in addressing pattern recognition problems is to define a representation that can be used for extracting the information content of signals. The sharp variation points of a signal amplitude are among the meaningful characterizations of the signal. The wavelet transform of the signal is found to be translation variant which makes it difficult for direct application in pattern recognition. However, the zero-crossings of a wavelet transform employing a particular class of wavelets can provide the translation invariant locations of the signal variation points. A zero-crossing representation augmented by the measure of the structure between the two consecutive zero-crossings has been studied by Stephane Mallat. On the basis of this representation, we demonstrate recognition of segments of biosignals embedded in streams of signals. The feasibility of employing zero-crossings of a wavelet transform as a tool in searching for a particular pattern class in the library of biosignals is explored.

Electrocardiography↗

Determining educational needs for the biomedical library customer: an analysis of end-user searching in MEDLINE.

The analysis of CD Plus usage logs provides an opportunity to determine specific areas where searchers are "missing opportunities" by misusing, or failing to use, system specific features. This paper describes a methodology, based on transaction log analysis, to provide automated, continuous analysis of end-user searching. The data collected in this process can then be used to enhance and provide insight into the educational needs of users.

CD-ROM↗

Initial assessment of gene diversity for the oomycete pathogen Phytophthora infestans based on expressed sequences.

A total of 1000 expressed sequence tags (ESTs) corresponding to 760 unique sequence sets were identified using random sequencing of clones from a cDNA library constructed from mycelial RNA of Phytophthora infestans. A number of software programs, represented by a relational database and an analysis pipeline, were developed for the automated analysis and storage of the EST sequence data. A set of 419 nonredundant sequences, which correspond to a total of 632 ESTs (63.2%), were identified as showing significant matches to sequences deposited in public databases. A putative cellular identity and role was assigned to all 419 sequences. All major functional categories were represented by at least several ESTs. Four novel cDNAs containing sequences related to elicitins, a family of structurally related proteins that induce the hypersensitive response and condition avirulence of P. infestans on Nicotiana plants, were among the most notable genes identified. Two of these elicitin-like cDNAs were among the most abundant cDNAs examined. The set also contained several ESTs with high sequence similarity to unique plant genes.

Actins↗

Mutagenesis using trinucleotide beta-cyanoethyl phosphoramidites.

There is no easy way to selectively introduce mixtures of codon triplets into mutagenesis libraries. Solid-phase-supported DNA synthesis using successive coupling of mixtures of mononucleotides can be made to supply 32 codons, which gives redundancies in coding for 20 natural amino acids, as well as an often unwanted stop codon. Resin-splitting methods have been described, but the representation of all permutations is limited by mechanical factors for a large library, and the method is experimentally cumbersome. To demonstrate a third, improved method, the 3'-cyanoethyl phosphoramidite codon triplets dATA, dCTT, dATC, dATG and dAGC were made by solution-phase methods, with protecting groups fully compatible with modern automated phosphoramidite DNA synthesis chemistry. The reagents were then used to synthesize a 54-mer DNA fragment, wherein 15 internal base pairs were randomized by coupling a mixture of the five codons five times. The fragment was amplified as a cDNA pool, which was subcloned into a phagemid vector, and 16 randomly selected recombinants from this mini-library were sequenced. These clones showed random incorporation of the proper transcribed codon sequences at the correct location. Other functional tests involving the trinucleotide phosphoramidites showed modest (ca. 70%) coupling efficiencies and structural integrity of the DNA produced.

Amino Acid Sequence↗

Continuing education needs of hospital librarians.

The Hospital Library Section (HLS) of MLA conducted a survey of its members to determine their continuing education needs and preferences. A questionnaire mailed with the HLS Newsletter gathered information in four general areas: preferred modes of continuing education, subjects viewed as most important, motivators and deterrents, and topics for presentation at the 1985 MLA annual meeting. Additional data were collected on the type and bed size of the member's institution. Of the 560 questionnaires mailed, 257 (46%) were returned. Overall, for continuing education, members favored one-day courses dealing with automated systems, planning and marketing; for annual meeting topics, they were additionally interested in health care finance.

Education↗

Automated liquid chromatographic/tandem mass spectrometric method for screening beta-blocking drugs in urine.

An automated liquid chromatographic/tandem mass spectrometric (LC/MS/MS) method is presented for the screening and confirmation of 16 beta-blocking drugs in clinical and autopsy urine samples. The described method involved C(18) solid phase extraction, LC separation and MS analysis on a triple-stage quadrupole mass analyser. Samples were initially pre-screened for the presence of any beta-blocking drugs using LC/MS with selected ion monitoring. Any compounds tentatively identified as beta-blocking drugs on the basis of their LC retention time and protonated molecular ion were then automatedly subjected to a second analysis in which the relevant MS/MS product ion mass spectra were acquired. These product ion mass spectra were then automatically searched against a 400-substance mass spectral library containing previously acquired beta-blocking drugs. The results demonstrated that library search of beta-blocking drugs in urine with MS/MS product ion mass spectra was more reliable and produced fewer false negatives than library searching with mass spectra derived from single-stage quadrupole MS. The limits of identification in the MS/MS product ion scan ranged from 0.02 mg l(-1) for carvedilol to 1.2 mg l(-1) for pindolol, the majority of the values being below 0.2 mg l(-1).

Adrenergic beta-Antagonists↗

Isolation, cloning, sequence analysis and localization of the operon encoding dimethyl sulfoxide/trimethylamine N-oxide reductase from Rhodobacter capsulatus.

The operon encoding the periplasmic enzymes dimethyl sulfoxide reductase (DMSOR) and trimethylamine N-oxide reductase (TMAOR) from the purple, non-sulfur, photosynthetic bacterium Rhodobacter capsulatus was isolated, cloned and sequenced, and its chromosomal location determined. It was shown by analytical and crystallographic data that DMSOR and TMAOR are identical enzymes. Degenerate primers were derived from short peptide sequences generated by automated Edman degradation and a 700 bp fragment was amplified by nested PCR, subsequently cloned and radioactively labeled to screen a prepared lambda DASH library. Positive lambda clones were subcloned into pBluescript and subsequently transformed into Escherichia coli to sequence the DMSOR/ TMAOR operon. The promoter consisted of an A + T-rich region followed by a -35 region, a putative ribosome binding site, and a leader sequence of 13 amino acid residues. The transcription terminator was a G + C-rich dyad sequence capable of forming a hairpin structure, which may act rho-independently. An optimized protein purification of the wild-type enzyme is also described, giving high yields (5 mg protein per liter of culture) and a specific activity of 30 units/mg. The molecular mass was determined by electrospray mass spectrometry to be 85,034 Da; from the deduced amino acid sequence the molecular mass of the apoenzyme was 85,033 Da.

Amino Acid Sequence↗

Microsatellite genotyping of carnation varieties.

A set of 11 sequence-tagged microsatellite markers for carnation (Dianthus caryophyllus) was developed using a DNA library enriched for microsatellites. Supplemented with three markers derived from sequence database entries, these were used to genotype carnation varieties using a semi-automated fluorescence-based approach. In a set of 82 cultivars, the markers amplified 4-16 alleles each. The effective number of alleles varied from 1.9 to 6.0. For the eight best scorable markers, heterozygosity was between 0.51 and 0.99. The markers were able to distinguish all cultivars with a unique combination of alleles, except for sport mutants, which were readily grouped together with the original cultivar. In addition, one group of three and one group of six cultivars each had the same combination of 'allelic peaks'. The cluster of three varieties concerned original cultivars and their mutants. The cluster of six consisted of four mutants from the same cultivar and two other varieties.

Base Sequence↗