Binge-drinking-related consequences in college students: role of drinking beliefs and mother-teen communications.

The present research contrasted theoretical models depicting the nature of the relation among drinking beliefs, drinking tendencies, and behavioral consequences in 266 incoming freshman college students. It also examined the theoretical relations between mother-teen communications and drinking beliefs relevant to behavioral consequences. The findings revealed direct relations between binge-drinking consequences and the drinking beliefs: Alcohol can make positive transformations, can enhance social behavior, and can increase negative affect and normative approval. Direct relations were not observed between consequences and the drinking beliefs regarding physical risk and health orientation. Finally, the present research found consistent support for the relation between mother-teen communications and drinking beliefs relevant to binge-drinking consequences.

College student drinking: an examination of theoretical models of drinking tendencies in freshmen and upperclassmen.

OBJECTIVE: The present research contrasted theoretical models of college student drinking tendencies (normative, social control, maturing out). METHOD: Three groups of students (N = 364; 62. 1% female) from a moderately sized northwestern university were examined: traditional freshmen, nontraditional freshmen and upperclassmen. Participants completed measures assessing drinking tendencies, drinking consequences and drinking beliefs. RESULTS: Support for a given theoretical model was dependent upon which outcome variables were being examined (e.g., drinking tendencies vs drinking consequences). Nontraditional freshmen were similar to their traditional freshmen counterparts in the amount of alcohol they consumed but were more like upperclassmen in the experience of consequences of drinking alcohol. Examination of drinking beliefs yielded inconsistent model support. CONCLUSIONS: It appears that different types of college students drink for different reasons, suggesting a "one size fits all" intervention is less likely to be effective. The findings are discussed with respect to different interventions for changing drinking tendencies, drinking consequences and drinking beliefs, and the timing of those interventions.

Examination of judgments of drunkenness, binge drinking, and drunk-driving tendencies in teens with and without a family history of alcohol abuse.

BACKGROUND: The present study examined judgment processes of individuals with and without a family history of alcohol abuse. Despite the alarming statistics involving alcohol-related consequences in this population, very little is known about what judgment processes they use or how beneficial these processes are at preventing intoxication and alcohol-related consequences. METHODS: Participants were 270 individuals, 16-18 years old, screened on the basis of the history of family alcohol abuse. Individuals were asked to (1) make judgments of drunkenness in relation to the legal limits in response to factorially manipulated external cues on number of drinks, time taken to consume, and type of beverage, using the methodology of Jaccard and Turrisi (1987), and (2) answer several questions regarding their alcohol-related behaviors. RESULTS: Our results indicated that individuals with a positive family history of alcohol abuse were more likely to make judgmental errors and underestimate their drunkenness relative to individuals without a positive family history of alcohol abuse. Moreover, the errors in judgments were more pronounced in situations involving moderate to heavy alcohol consumption. Finally, family history was found to moderate the relationship between underestimation errors and drinking, and drinking and driving tendencies. For individuals with a positive family history of alcohol abuse, the more they tended to underestimate their drunkenness, the more likely they were to binge drink and drive after drinking. CONCLUSIONS: The findings suggest that judgmental errors tend to be an important process variable in the relationship between family history and alcohol-related behavioral tendencies. The findings are discussed with respect to potential behavioral antecedents (e.g., student binge drinking) and development of prevention programs geared toward training students to make more accurate judgments, using external cues.

Transformation in Bacillus subtilis: further characterization of a 75,000-dalton protein complex involved in binding and entry of donor DNA.

A 75,000-dalton protein complex purified from membranes of competent Bacillus subtilis cells was previously shown to be involved in both binding and entry of donor DNA during transformation. The complex, consisting of two polypeptides, a and b, in approximately equal amounts, showed strong DNA binding as well as nuclease activity (H. Smith, K. Wiersma, S. Bron, and G. Venema, J. Bacteriol. 156:101-108, 1983). In the present experiments, peptide mapping indicated that the two polypeptides are not related. Chromatography on benzoylated, naphthoylated DEAE-cellulose showed that polypeptide b generated single-stranded regions in double-stranded DNA. A considerable amount of the DNA was rendered acid soluble by polypeptide b. The nuclease activity of polypeptide b was reduced in the presence of polypeptide a. This resulted in an increased fraction of high-molecular-weight double-stranded DNA containing single-stranded regions. The acid-soluble DNA degradation products formed by polypeptide b consisted exclusively of oligonucleotides. In contrast to its nuclease activity, which was specifically directed toward double-stranded DNA, the DNA binding of the native 75,000-dalton complex to single-stranded DNA was at least as efficient as to double-stranded DNA.

Transformation in Bacillus subtilis: a 75,000-dalton protein complex is involved in binding and entry of donor DNA.

A 75,000-dalton protein complex involved in DNA binding during transformation was purified from membranes of competent Bacillus subtilis cells. Previous results (Smith et al., J. Bacteriol. 156:101-108, 1983) showed that the complex contained two polypeptides, polypeptide a (molecular weight, 18,000; isoelectric point, 5.0) and polypeptide b (molecular weight, 17,000; isoelectric point, 4.7) in approximately equal amounts. In the present experiments the two polypeptides were extracted from two-dimensional gels and studied separately and in combination with respect to DNA binding and nuclease activities. For DNA binding the interaction of both polypeptides was required. DNA binding occurred efficiently in the presence of EDTA. Nuclease activity was restricted to polypeptide b. The nucleolytic properties of b were identical to those of the native 75,000-dalton complex. Polypeptide a affected b by reducing its nuclease activity. Analysis of the nuclease subunit b on DNA-containing polyacrylamide gels revealed nuclease activities at four different molecular weight positions. These activities were identical to the major competence-specific nuclease activities which were previously implicated in the entry of donor DNA during transformation (Mulder and Venema, J. Bacteriol. 152:166-174, 1982). These results indicate that the 75,000-dalton protein complex is composed of two different competence-specific polypeptides involved in both binding and entry of donor DNA. The possible roles of the two polypeptides in the transformation of B. subtilis are discussed.

Involvement of single-strand breaks in complex formation between single-stranded DNA and nucleoids of Bacillus subtilis.

RNase-unfolded chromosomes of competent Bacillus subtilis are able to take up single-stranded homologous donor DNA fragments in vitro to form donor-recipient DNA complexes (Van Randen and Venema 1981). The unfolded chromosomes behave as supercoiled DNA molecules. X-irradiation increased the formation of unstable and stable complexes between donor and recipient DNA during incubation at 37 degrees C. The complex-forming ability of the unfolded chromosomes increased linearly with increasing X-ray dose, even after complete relaxation of the unfolded chromosomes had occurred. Limited DNase I action increased the complex-forming ability of the chromosomes as effectively as X-irradiation. Unstable donor-recipient DNA complexes can be distinguished from stable ones by their dissociation upon density gradient centrifugation in CsCl at pH 11.2. They are stable at pH 10 (Van Randen et al. 1982a). At an intermediate pH value during isopycnic centrifugation, a fraction of the unstable complexes were stable, suggesting that a range of stabilities existed among the unstable complexes. The donor moiety of the stable donor-recipient DNA complexes was far more resistant to nuclease S1 treatment than that of the unstable ones.

Transformation in Bacillus subtilis: purification and partial characterization of a membrane-bound DNA-binding protein.

In DNA binding-deficient mutants of Bacillus subtilis a competence-specific protein with a subunit molecular weight of 18,000 was absent. The native protein containing this subunit was purified from B. subtilis membranes by chromatography on hydroxyapatite, DEAE-cellulose, and Sephacryl S-200. This protein appeared to be complexed with a second protein of slightly lower molecular weight (17,000) and a different isoelectric point. The native protein complex (apparent molecular weight, 75,000) contained approximately equal amounts of the two polypeptides and showed a strong DNA-binding activity. Incubation of the complex with plasmid and bacteriophage DNA revealed nuclease activity, specifically directed toward double-stranded DNA. Predominantly single-stranded nicks and a limited number of double-stranded breaks were introduced in the presence of Mg2+ ions. In the presence of Mn2+ ions the complex produced low-molecular-weight breakdown products from the DNA.

Unstable association in vitro between donor and recipient DNA in Bacillus subtilis.

In addition to stable donor-recipient DNA complexes, unstable complexes between donor and recipient DNA were formed in vitro with Bacillus subtilis. Whereas the stable complexes survived CsCl gradient centrifugation at pH 11.2 and phenol plus sodium p-aminosalicylate extraction with 0.17 M NaCl, the unstable complexes dissociated during these manipulations. The donor moiety from the unstable complexes remained associated with the recipient DNA during phenol plus sodium p-aminosalicylate treatment at 0.85 M NaCl. The unstable complexes could be stabilized artificially by cross-linking with 4,5',8-trimethylpsoralen. Dissociation of the complexes during CsCl gradient centrifugation could be prevented by centrifuging at pH 10. Heterologous DNA fragments derived from phage H1 DNA appeared to be unable to form complexes with the recipient B. subtilis DNA. Unstable complexes were also formed with Escherichia coli DNA, although under all conditions tested, more complex was detectable by using homologous B. subtilis DNA.

Initiation of recombination during transformation of Bacillus subtilis requires no extensive homologous sequences.

Lysates obtained shortly after entry of transforming DNA to Bacillus subtilis contain donor-recipient DNA complexes, in which the donor moiety is associated with the recipient DNA in an unstable way. The complexes could be artificially stabilized by crosslinking with 4,5',8-trimethylpsoralen. The unstable complexes dissociated upon helix-destabilizing treatments, such as heating at 70 degrees C, and CsCl gradient centrifugation at pH 11.2, but remained stable during CsCl gradient centrifugation at pH 10. Donor-recipient DNA complexes were not formed after entry of heterologous pUB110 DNA. These observations suggest that base-pairing is involved in the unstable association. The donor moiety of the unstable complexes was completely, or almost completely, digestible by nuclease S1, indicating that the donor and recipient base-sequences are only paired over very short distances. The unstable donor-recipient DNA complexes are true recombination intermediates because (i) strain 7G224 (recE4) was impaired in the formation of the unstable complexes, and (ii) the unstable complexes were rapidly converted to stable complexes in recombination proficient strains, whereas their conversion was delayed in the recombination deficient strain 7G84. Unstable complexes were also formed with Escherichia coli donor DNA, but to a lesser extent. Apparently a limited degree of base-sequence homology is sufficient to initiate recombination.