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D C Schroeder

Publications and source records attributed to D C Schroeder.

11 recordsLinked to original sources
PubMed2005

Preliminary characterisation of repeat families in the genome of EhV-86, a giant algal virus that infects the marine microalga Emiliania huxleyi.

EhV-86 is a large double stranded DNA virus with a 407,339 base pair circular genome that infects the globally important microalga Emiliania huxleyi. It belongs to a new genus of viruses termed the Coccolithoviridae within the algal virus family Phycodnaviridae. By plotting the EhV-86 genome against itself in a dot-plot analysis we revealed three families of distinctly different repeat sequences throughout its genome, designated Family A, B and C. Family A repeats are non-coding, found immediately upstream of 86 predicted coding sequences (CDSs) and are likely to play a crucial role in controlling the expression of the associated CDSs. Family B repeats are GC rich, coding and correspond to possible calcium binding sites in 22 proline-rich domains found in the protein products of eight predicted EhV-86 CDSs. Family C repeats are AT-rich, non-coding and are likely to form part of the origin of replication. We suggest that these repeat regions are of fundamental importance during virus propagation being involved with transcriptional control (Family A), virus adsorption/release (Family B) and DNA replication (Family C).

Base Composition↗
PubMed2002

Coccolithovirus (Phycodnaviridae): characterisation of a new large dsDNA algal virus that infects Emiliana huxleyi.

Emiliania huxleyi-specific viruses ( EhV) were isolated from E. huxleyi blooms off the coast of Plymouth, UK, in July 1999 and July/August 2001, and from an E. huxleyi bloom induced during a mesocosm experiment in a fjord off Bergen, Norway, during June 2000. Transmission electron microscopy revealed that all 10 virus isolates are 170-200 nm in diameter with an icosahedral symmetry. Their density is approximately 1.2 in CsCl gradients and they have large double stranded DNA genomes approximately 410 kb in size. Phylogenetic analysis of the DNA polymerase genes of these viruses suggests that EhV belongs to a new genus within the family of algal viruses, Phycodnaviridae. We propose to name this new virus genus Coccolithovirus. Differences within members of the Coccolithovirus were elucidated by host range analysis of the virus isolates and sequence analysis of a gene fragment encoding part of their putative major capsid protein. All 10 virus isolates within this new genus only infected E. huxleyi strains that have previously been shown to exhibit low dimethylsulphoniopropionate lyase (DMSP-lyase) activity (CCMP1516, CCMP374 and L), while E. huxleyi strains with high DMSP-lyase activity (CCMP373 and CCMP379) were resistant to infection.

Base Sequence↗
PubMed1987

The analysis of nitrate in environmental samples by reversed-phase HPLC.

A method is presented for the analysis of nitrate in natural waters and waste water by high-performance liquid chromatography (HPLC) with a reversed-phase octadecyl column, aqueous phosphoric acid/dihydrogen phosphate mobile phase, and UV detector. The optimum nitrate concentration is 0.3 to 3 mg/L as N with linear detector response below 3 mg/L. The detection limit is 0.007 mg/L. Relative standard deviations in the optimum range are consistently less than one percent. Several potential interferences have been investigated; nitrite and organic chromophores are resolved from nitrate and do not interfere. Hexavalent chromium and sulfate are slight positive interferences, negligible at typical environmental concentrations. The method produces results in agreement with the accepted chromotropic acid method except in samples from eutrophic lakes, for which evidence is presented indicating that the chromotropic acid is inaccurate.

Chromatography, High Pressure Liquid↗
PubMed1984

Computerized method for the graphic representation of multivariate periodontal data.

Appreciation of the multivariate features of data from periodontal research studies is sometimes difficult. This appears to be due to the form of tables and graphs in which information is made available in published studies. A computerized graphical technique, which appears well suited to the multivariable situation, is described. It uses structural analogy between the measurement scales and the variables measured and provides what can be a compelling iconic description of multifaceted data.

Computers↗
PubMedDate not supplied

Frequency of dental trait anomalies in cleft, sibling, and noncleft groups.

The incidence and types of dental trait anomalies found in individuals with cleft lip or cleft palate or both (cleft group), in siblings of the cleft group, and in a group of individuals without cleft lip or cleft palate (noncleft group) were compared. The cleft group had 1.02 anomalies per individual, the sibling group, 0.38; and the noncleft group, 0.17. The frequency of occurrence of thick-curved maxillary central incisors, incisal fissures, and missing teeth were significantly different among the three groups.

Adolescent↗
PubMedDate not supplied

Arizona providers' use and knowledge of fluoride supplements.

Dietary fluoride supplements are recommended for dental caries prevention in children without access to optimally fluoridated water. Previous studies have shown deficiencies in dentists' and physicians' knowledge about dietary fluoride supplementation. Data were collected from dentists, physicians and other healthcare provider groups to assess dietary fluoride supplement knowledge and practices. Pediatricians and dentists were found to be the most knowledgeable concerning the recommended prescribing protocols. Substantial proportions of all practitioner groups had insufficient knowledge about the recommended dosages of dietary fluoride supplements by age, fluoride levels in local water supplies, and the effectiveness of fluoride delivery methods. Baseline knowledge and practices were determined for healthcare provider groups within Arizona.

Arizona↗