Development of the Affect for Communication Channels Scale

As computers have increasingly provided new channels of communication, scholars have taken an interest in computer-mediated communication (CMC) in general and the impact of personality traits and other antecedents of preference for face-to-face or computer channels. Research is hampered, however, by the lack of standardized measures of CMC-related concepts. Three studies ( N = 914) were undertaken to develop and validate a measure of affect for using communication channels. Findings of the studies provide strong evidence of the internal consistency and both construct and predictive validity of the scale.     

Effects of Primers and Taq Polymerase on Randomly Amplified Polymorphic DNA Analysis for Typing Listeria monocytogenes From the Environment of a Shrimp Processing Plant

Ninety-nine randomly selected isolates of Listeria monocytogenes from several processing environment locations, in a shrimp processing plant, obtained during a 5-month sampling period were subjected to randomly amplified polymorphic DNA (RAPD) analysis with the use of four primers. Preliminary studies indicated that the number of DNA bands and their intensity differed greatly with respect to the commercial source of the Taq polymerase used with individual isolates. Eighteen composite RAPD types were discerned with the use of the four primers. Among these 18 composite RAPD types, type 1 comprised 14 indistinguishable isolates, and type 9 comprised 49 indistinguishable isolates. These results indicate that the shrimp processing plant was dominated by these 2 RAPD types that comprised 63.6% of the 99 randomly selected isolates.     

Sex-related alcohol expectancies among adolescents: I. Scale development.

A measure of sex-related alcohol expectancies was developed with a total of 916 sexually experienced adolescents (aged 13–19 yrs) who had ever consumed alcohol. The sample was 52.6% male, 48% White, and 44% Black. Expectancy items represented 3 domains: enhancement of sexual experience, increased sexual risk taking, and disinhibition of sexual behavior. Confirmatory analyses showed that a 3-factor model provided a good fit to the data. Adequate reliability and low-to-moderate correlation among the expectancy measures were also demonstrated. Expectancies for sexual risk taking and disinhibition were found to be more strongly endorsed by male than by female respondents, although these differences were stronger among Black than among White adolescents and increased with age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Utilisation of the budding yeast Saccharomyces cerevisiae for the generation and isolation of non-lethal ricin A chain variants

Knowledge of the uptake, membrane translocation, refolding and ribosome interaction of the ribosome-inactivating toxin ricin is incomplete at the present time. Ricin A chain (RTA) is the catalytic subunit of holotoxin and is also of particular interest as a vaccine candidate. For many studies into the uptake and immunological applications of ricin, it is essential to have inactive variants. Here, following error-prone polymerase chain reaction of the RTA open reading frame, we have used a modified gap-repair protocol in Saccharomyces cerevisiae to show that it is possible to rapidly generate a panel of inactive RTA mutants. Since yeast cells have ribosomes that are highly sensitive to RTA, we utilized a genetic selection based on the viability of transformants. This enabled the recovery of a number of mutations, some not previously identified, which permitted production of full-length but non-toxic RTA proteins. Such disarmed toxins may have utility as tools to study the cytosolic entry and action of RTA, and as potential vaccine candidates.     

Effects of Primers and Taq Polymerase on Randomly Amplified Polymorphic DNA Analysis for Typing Listeria monocytogenes From the Environment of a Shrimp Processing Plant

Ninety-nine randomly selected isolates of Listeria monocytogenes from several processing environment locations, in a shrimp processing plant, obtained during a 5-month sampling period were subjected to randomly amplified polymorphic DNA (RAPD) analysis with the use of four primers. Preliminary studies indicated that the number of DNA bands and their intensity differed greatly with respect to the commercial source of the Taq polymerase used with individual isolates. Eighteen composite RAPD types were discerned with the use of the four primers. Among these 18 composite RAPD types, type 1 comprised 14 indistinguishable isolates, and type 9 comprised 49 indistinguishable isolates. These results indicate that the shrimp processing plant was dominated by these 2 RAPD types that comprised 63.6% of the 99 randomly selected isolates.     

Low concentration of ethylenediaminetetraacetic acid (EDTA) affects biofilm formation of Listeria monocytogenes by inhibiting its initial adherence

The distribution and survival of the food-borne pathogen Listeria monocytogenes is associated with its biofilm formation ability, which is affected by various environmental factors. Here we present the first evidence that EDTA at low concentration levels inhibits the biofilm formation of L. monocytogenes. This effect of EDTA is not caused by a general growth inhibition, as 0.1 mM EDTA efficiently reduced the biofilm formation of L. monocytogenes without affecting the planktonic growth. Adding 0.1 mM of EDTA at the starting time of biofilm formation had the strongest biofilm inhibitory effect, while the addition of EDTA after 8 h had no biofilm inhibitory effects. EDTA was shown to inhibit cell-to-surface interactions and cell-to-cell interactions, which at least partially contributed to the repressed initial adherence. The addition of sufficient amounts of cations to saturate EDTA did not restore the biofilm formation, indicating the biofilm inhibition was not due to the chelating properties of EDTA. The study suggests that EDTA functions in the early stage of biofilm process by affecting the initial adherence of L. monocytogenes cells onto abiotic surfaces.