Arabinogalactan protein and wall-associated kinase (WAK) are suspected to be regulatory players at the interface between cytoplasm and cell wall. Both WAK(s) and arabinogalactan shown likely to represent arabinogalactan protein(s) have been visualized there with computational optical-sectioning microscopy. The arabinogalactan occurs in a polyhedral array at the external face of the cell membrane. WAK, and other proteins as yet unidentified, appear to fasten the membrane to the wall at vertices of the array. Evidence is presented that the array bears an important part of the mechanical stress experienced by the membrane, and it is speculated that the architectural organization of arabinogalactan protein, WAK, and other components of the array is critical for coordination of endomembrane activities, growth, and differentiation. The array has been named the plasmalemmal reticulum.

Antibodies, Monoclonal↗

PubMedDate not supplied

Comprehension monitoring skills of adults with mental retardation.

The ability of 30 adults with mild and moderate levels of mental retardation to monitor their comprehension while performing a direction-following task was examined. Subjects were "employed" to aid the investigator in compiling objects for gift bags. The task consisted of 60 directions (e.g., "Give me a blue pencil"), of which 6 contained trouble sources (ambiguous directions, unintelligible words, and compliance problems). Each subject's response to the directions involving trouble sources was scored to determine if the subject (a) demonstrated effective comprehension monitoring (as indicated by an immediate awareness of the problem and effective attempt to rectify the problem), (b) requested clarification after attempting to comply with the direction and being unable to do so, (c) demonstrated ineffective comprehension monitoring (as indicated by an awareness of the problem but an ineffective means of dealing with it), or (d) showed no awareness of the trouble source. The ability of subjects to monitor comprehension varied with type of trouble source. Ambiguous trouble sources were the most difficult for the subjects to detect, and compliance-problem trouble sources were the most frequently identified.

Adult↗

PubMedDate not supplied

Responses to requests for clarification by older and young adults with mental retardation.

This study compared the ability of young (mean chronological age = 29 yrs., SD = 3.67 yrs.) and older adults (chronological age = 63 yrs., SD = 5.54 yrs.) with mild to moderate mental retardation to respond to stacked requests for clarification in conversation. Data were collected in dyadic conversations between subject and investigator. During the course of the conversation, the investigator introduced stacked sequences of three requests for clarification of the same message ("Huh?", "What?", "What?"). Neither group of subjects was as responsive to the requests for clarification as would have been predicted based on their general cognitive and linguistic levels of functioning. Few significant differences were observed between the young and older groups.

Adult↗