Identification of cell wall antigens associated with a large conjugative plasmid encoding phage resistance and lactose fermentation ability in lactic streptococci

In order to begin to analyze the gene products encoded by phage resistance plasmids in lactic streptococci, we identified phage-resistance plasmids by screening resistant strains from commercial starter cultures for the ability to carry out unselected cotransfer, by conjugation, of phage resistance with lactose fermentation ability (lac+). In this fashion, we identified a large (90 kilobases) plasmid, pCLP51R, that encodes the lac+ marker, resistance to a lytic phage called LP10G (1pr+), high-frequency conjugal donor ability (hft+), and clumpy growth of host bacteria in broth culture (clu+). The mechanism of resistance conferred by this plasmid appears to involve interference with a step in the phage replication cycle that occurs after the initial attachment of the phage. Polyacrylamide gel electrophoresis of cell surface extracts of isogenic strains, carrying or lacking pCLP51R, combined with immunoblotting analysis, showed that there were several plasmid-related differences in the banding pattern of low molecular weight proteins and that the plasmid resulted in production of several unique antigenic polypeptides in the size range of 15-30 kd, as well as modification of chromosomally encoded antigens to different molecular weight forms.

A matched sample investigation of nonadaptive behavior of severely handicapped adults across four living situations

Specific nonadaptive behavior characteristics of severely handicapped adults from state and private institutions, group homes, and parents' homes were investigated. No significant differences were found between the total population sampled and a sample matched on the demographic variables of CA, language age, sex, and diagnosis. Results of postpriori analysis of the 6 out of 57 types of nonadaptive behavior found to be significantly different across residential categories showed that the state institution population had significantly higher amounts of nonadaptive behavior than did persons from all other residential categories. No significant nonadaptive behavior differences were found between residents of private institutions, group homes, or parents' homes. State institution subjects had more severe behavior-management problems and fewer job placements than did persons from all other residential categories.

Auditory brainstem evoked responses in autistic children

Previous studies have implicated a brainstem dysfunction in the syndrome of autism. This study matched six autistic children with six normal children by age and sex to evaluate brainstem evoked response (BSER) to auditory stimuli. An evaluation of pure tone audiometric threshold showed no evidence of impairment; however, the electrophysiologic responses differed for the autistic and control groups. The BSER of the autistic children was remarkable for showing increased latency and markedly increased variability. The findings from this study add additional evidence of a brainstem dysfunction in autistic children, while the electrophysiologic variability supports the hypothesis of perceptual inconstancy.

Autistic children: a study of learning characteristics and programming needs

Learning-acquisition characteristics of six autistic children were studied in order to examine programming needs. Two studies were conducted. Study 1 showed that the first step of a color-cued sequencing task required four times more trials to learn than did the remaining five steps, producing a significant learning-to-learn curve. Study 2 confirmed earlier findings that extra-stimulus prompts are comparatively ineffective with autistic children when compared to within-stimulus prompts and showed extra-stimulus prompting to be effective following the use of within-stimulus prompting on a similar task.

Evaluation of a program of systematic instructional procedures for extremely poor retarded children

A demonstration program was conducted in which 54 innercity children classified as educable mentally retarded were selected on the basis of age, IQ, family income, race, and achievement scores. They were then placed into self-contained classrooms with two classes being taught by precision-teaching procedures and two classes being taught by the methods particular to their teachers. Tesults showed that a high percentage (60 percent) of the children taught by precision-teaching procedured were capable of acquiring the basic skills necessary for regular-class placement.