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S S Cox

Publications and source records attributed to S S Cox.

10 recordsLinked to original sources
PubMed1986

rpe, a cis-acting element from the strA region of the Haemophilus influenzae chromosome that makes plasmid establishment independent of recombination.

Plasmids that share homology with the Haemophilus influenzae chromosome transform wild-type cells more efficiently than they transform recombination-defective mutants. A 5.2-kilobase-pair chromosomal fragment containing the strA gene of H. influenzae was found to promote efficient plasmid establishment in recombination-defective mutants. A cis-acting element in the insert, called rpe for rec-less plasmid establishment, promoted plasmid transformation in rec-1 and rec-2 mutants without suppressing the recombination defects of these strains. The rpe locus increased plasmid transformation in wild-type cells without interfering with the pathway of plasmid establishment that is dependent on recombination functions.

Chromosome Mapping↗
PubMed1984

Nitrogen fixation and nitrogenase activities in members of the family Rhodospirillaceae.

Strains of all 18 species of the family Rhodospirillaceae (nonsulfur photosynthetic bacteria) were studied for their comparative nitrogen-fixing abilities. All species, with the exception of Rhodocyclus purpureus, were capable of growth with N2 as the sole nitrogen source under photosynthetic (anaerobic) conditions. Most rapid growth on N2 was observed in strains of Rhodopseudomonas capsulata. Within the genus Rhodopseudomonas, the species R. capsulata, R. sphaeroides, R. viridis, R. gelatinosa, and R. blastica consistently showed the highest in vivo nitrogenase rates (with the acetylene reduction technique); nitrogenase rates in other species of Rhodopseudomonas and in most species of Rhodospirillum were notably lower. Chemotrophic (dark microaerobic) nitrogen fixation occurred in all species with the exception of one strain of Rhodospirillum fulvum; oxygen requirements for dark N2 fixation varied considerably among species and even within strains of the same species. We conclude that the capacity to fix molecular nitrogen is virtually universal among members of the Rhodospirillaceae but that the efficacy of the process varies considerably among species.

Culture Media↗
PubMedDate not supplied

Is there a shortage of dental hygienists?

Dental hygiene faculty from the Ohio State University, working under a grant from the Ohio Dental Association, surveyed licensed dentists and dental hygienists in Ohio in order to determine work-related concerns and possible solutions to perceived shortages of hygienists. There were 585 respondents from those selected through stratified systematic sampling based on state dental district for a 69% rate of dentist return and a 73% rate of hygienist return. The joint surveys assessed attitudes and documented experiences in several categories: practice background, opinion about hygiene employment shortage, compensation, aspects of hygiene satisfaction, reasons for ever terminating hygiene practice and future conditions persuading a return to hygiene practice. This article, the first in a series, presents findings from the survey of dentists relative to a perceived shortage of clinical dental hygienists. Forty-eight percent of dentist respondents believe that there is a shortage, while 52% are either not sure or believe there is no shortage. Those sensing a shortage have either tried to find a hygienist and could not believe there is a smaller pool to choose from, or have heard that colleagues have been unable to find a hygienist. Solutions to the shortage focus on better recruitment of qualified students, encouraging reentry of non-practicing hygienists, and promoting retention of hygienists in existing practices. Less frequently, dentists suggest starting new hygiene programs or training hygienists by preceptorship.

Dental Hygienists↗